M144-41-2007E .
To obtain additional copies of this or other free publications
on energy efficiency, please contact
Energy Publications
Office of Energy Efficiency
Natural Resources Canada
c/o St. Joseph Communications
Order Processing Unit
1165 Kenaston Street
PO Box 9809 Station T
Ottawa ON K1G 6S1
Tel.: 1-800-387-2000 (toll-free)
Fax: 613-740-3114
TTY: 613-996-4397 (teletype for the hearing-impaired)
Revised March 2007
Cat. No. M144-41/2007E (Print)
ISBN 978-0-662-45915-6
Cat. No. M144-41/2007E-PDF (On-line)
ISBN 978-0-662-45500-4
© Her Majesty the Queen in Right of Canada, 2007
Recycled paper
Aussi disponible en français sous le titre : Emprisonnons la chaleur
Keeping the Heat In
INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
How Your House Works . . . . . . . . . . . . . . . . . . . . . . . . . . 6
The Basics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Control of Heat Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Control of Airflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Control of Moisture Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
The House as a System in Action . . . . . . . . . . . . . . . . . . . . . . 21
Older Homes and Heritage Buildings . . . . . . . . . . . . . . . . . . 22
Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Air-Barrier Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Vapour-Barrier Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Health and Safety Considerations . . . . . . . . . . . . . . . . . . . . . 40
Special Health Considerations . . . . . . . . . . . . . . . . . . . . . . . . 43
Comprehensive Air-Leakage Control . . . . . . . . . . . . . . 44
Finding Leakage Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Caulking and Other Air-Sealing Materials . . . . . . . . . . . . . . . 48
Roofs and Attics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
General Considerations for All Attics . . . . . . . . . . . . . . . . . . . 55
Easily Accessible Attics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Houses with Half Storeys. . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Special Cases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Renovations and Repair. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Basement Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
How to Insulate Outside the Basement . . . . . . . . . . . . . . . . . 79
How to Insulate Inside the Basement. . . . . . . . . . . . . . . . . . . 84
Crawl Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Open Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Concrete Slab on the Ground . . . . . . . . . . . . . . . . . . . . . . . . 93
Insulating Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Blown-In Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Renovating the Interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Renovating the Exterior. . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Miscellaneous Spaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Additions and New Construction . . . . . . . . . . . . . . . . . . . . 105
Upgrading Windows and Doors . . . . . . . . . . . . . . . . . 106
Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Operating Your House . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Operating and Maintaining the Heating System . . . . . . . . . 115
The Heating System and Ventilation and Combustion Air . . 118
Other Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Dollars and Sense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Need More Information?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Keeping the Heat In
How Your House Works
Chapter 1
Chapter 2
Air-Leakage Control
Chapter 3
Roofs and Attics
Chapter 4
What Is Retrofitting?
Retrofitting a house is simply upgrading
it so that it will keep the heat in. This
means adding insulation, caulking and
weatherstripping, improving or replacing windows and doors, and improving
the heating system. Retrofitting also
means including energy-efficiency measures in all your renovation and repair
activities. In our climate, retrofitting
usually makes a lot of sense.
About This Book
This book tells you how to go about
retrofitting your home. It deals with
houses of all kinds in all parts of Canada.
It does not deal with apartment or commercial buildings, although some of the
information presented here may be useful.
This book is designed to serve both the
experienced do-it-yourselfer and the
novice willing to give it a try. It is also a
useful consumer guide for homeowners
who intend to hire a contractor to
undertake retrofit work.
If you rent, this book offers many lowcost measures that will save you money
and make your house more comfortable.
Be sure to read Chapters 3, 7 and 8,
which look at air sealing, windows and
doors, and how to operate your house.
Keeping the Heat In • Introduction
Basement Insulation
Chapter 5
Insulating Walls
Chapter 6
You may want to make up a list of
recommended measures and approach
the landlord with your suggestions. If
the landlord pays the heating bill, the
benefits are obvious. If you pay the heating bill, the landlord will have a happy
tenant and a more valuable house.
Why Retrofit?
Energy Efficiency
Perhaps most important, retrofitting a
home costs less than producing new
energy supplies to heat it. Fully 15 percent of Canada’s annual energy use is to
heat our homes, and this energy comes
mostly from non-renewable resources
such as oil and gas.
A well-insulated, air-sealed house is a
comfortable home. An insulated, tighter
house is also a much quieter house,
and there is less dust and pollen to
worry about.
A Sound House
By considering energy efficiency as part
of your home’s maintenance and repair,
your house will be in better shape. And
by improving your home’s air and moisture control, your retrofit work should
last longer and look better.
Windows and Doors
Chapter 7
Operating Your House
Chapter 8
Save Money
Improving your home’s energy efficiency
is one of the best investments you can
make, paying tax-free dividends immediately in the form of lower heating
costs. Home insulation is better than
just about any other low-risk, long-term
investment you can make.
All this aside, the investment is still a
good one since it is an investment in
the conservation of our valuable energy
supplies, and this means we all benefit
from environmental conservation.
Retrofit Opportunities
What retrofit strategies are best for you?
You will have to determine what shape
your house is in and what can be done
to improve it.
Check the interior and exterior for signs
of moisture damage and structural problems, maintenance and repair needs,
renovation opportunities, the level and
condition of insulation, and air-leakage
paths. Some utilities offer an audit
service to help you assess your needs;
call your local utility to see if this service
is available. Some contractors also offer
assessments; check your local Yellow
Pages™ directory.
Dollars and Sense
Chapter 9
Although each house is unique, some
general statements can still be made
about retrofit opportunities.
• Virtually all houses will benefit from
air-leakage control. Weatherstripping
and sealants will stop drafts, save
money, improve comfort and protect
the structure. See Chapters 3 and 7
for details. You should also consider
moisture control and ventilation to
reduce the chance of condensation
• Many houses will benefit from a
complete heating-system tune-up.
This should analyse and correct any
problems with the furnace or boiler,
the distribution system and the
controls. Upgrading or replacing the
unit with a high-efficiency model
will provide substantial savings. See
Chapter 8 for a summary.
• Insulate a poorly insulated attic. If
there is less than 150 mm (6 in.)
of insulation in the attic, it will be
worthwhile putting more in. It is
important to provide a good air seal
first. See Chapter 4 for details.
• Insulate an empty frame wall. If there
is no insulation in a frame wall, it is
worthwhile blowing in insulation to
fill the cavity. See Chapter 6 for details.
Keeping the Heat In • Introduction
• Insulate the basement. Basements
are areas of significant heat loss in
most houses. If the insulating can be
combined with damp-proofing on
the exterior or finishing the inside, it
will be doubly worthwhile. See
Chapter 5 for details.
• Make the most of repair and renovation work. Almost all repairs and
renovations you do around the house
can have an energy-efficient component piggybacked onto the work.
You will find useful ideas throughout
this book.
• Other opportunities for retrofit may
be right for you. If you think that any
part of your house can be made more
energy efficient, consult the relevant
chapter in this book for details.
Chapter 8 has many good suggestions for other ways to save energy
around the home.
How to Use This Book
Every homeowner should read Chapters
1, 2 and 8. This will provide important
background information on retrofit
techniques and materials. Read other
chapters as required for specific details.
Why not skim through each chapter to
see what might be right for your house
and renovation plans? Remember,
improving the energy efficiency of your
house is an ongoing process – it is
accomplished bit by bit as you work on
your house over the years. Keep this
book as a handy reference.
Some Important Things to Keep
in Mind
House as a System
Experts at Natural Resources Canada
have gained a lot of experience with
retrofit work over the last three decades.
One of the most important lessons is
that a house works as a system. Each
part of the house is related to all other
parts, and making a change in one place
causes an effect elsewhere.
There are many forces at work in a
house: structural loading, the effects of
wind and weather, and flows of moisture, heat and air. These must be kept in
the right balance. Adding insulation, air
barriers and vapour barriers can affect
moisture conditions, ventilation and
combustion air. Chapter 1 discusses
this in detail and should be read by all
Keeping the Heat In • Introduction
Do It Yourself or Hire a Contractor
Much retrofit work can be done by the
do-it-yourselfer with a few special tools
and the right materials. The cost savings
and job satisfaction can both be high.
If you take the trouble to do the job
properly, the results should be excellent.
Make sure you consult this book carefully. It is designed to meet the needs of
both the experienced and inexperienced
The house as a system:
air, moisture and heat flows all interact.
Health and Safety
Codes and Standards
Approach any work around the house
with your health and safety in mind.
Most health and safety rules amount to
using common sense around ladders
and tools, and when working in
cramped and stuffy conditions such
as in attics. Also, insulation and sealing
materials must be handled and installed
with care. Chapter 2 describes some
general health and safety considerations.
Chapters 4 to 7 describe measures that
are specific to working in different areas
of the house.
Materials specifications, installation procedures and construction techniques are
normally spelled out in codes and standards or in the manufacturers’ literature.
Typically, these concentrate on health
and safety issues, such as ventilation and
fire-safety requirements. Each province
or territory and most municipalities
have jurisdiction over their respective
building codes. The information in this
book, written for readers across Canada,
is general in nature. Local codes should
be followed. Check with your local
municipal office and building inspector.
Some types of retrofit are best done by a
contractor with specialized equipment
and experience, or you may just prefer
to have someone do the work for you.
You are far more likely to have excellent
work done if you choose a contractor
carefully and take an active interest in
the work. The more you know, the
better. This is especially important if
you are hiring a contractor to undertake
general renovations and you want to
include energy efficiency as part of
the work.
1How Your House Works
Keeping the Heat In
The Basics
Part I
It is important to understand how your
house works before starting any retrofit
work. This will ensure that the job will
meet your expectations and that you
won’t be causing new problems while
solving old ones.
This chapter will describe the basic
building science that is important for
successful retrofit work. It will explain
how building-science principles are used
successfully to control the flow of heat,
air and moisture and why these should
be considered together.
Keeping the Heat In 1 How Your House Works
Control of Heat Flow
Part II
Control of Airflow
Part III
House Performance
We expect our homes
to provide shelter from
the sun, rain, wind and
snow, and we expect them
to keep us warm and comfortable.
We also expect that they will be sturdy
and durable.
A number of factors work together to
meet these needs. These include the
building shell, the outside environment,
the mechanical system and ourselves,
the occupants. This book is mainly
about improving the performance of the
house envelope.
The Building Envelope
The building envelope is the shell of
the house that protects us from the
elements; it comprises the basement
walls and floor, the above-grade walls,
the roof and the windows and doors.
We expect a lot from the envelope: it
must provide structural support for the
walls and roof, protect the structure
from deterioration, allow for natural
lighting of the interior and serve as a
means of getting in and out. Finally, the
envelope must separate our warm and
Control of
Moisture Flow
Part IV
The House as a
System in Action
Part V
Older Homes and
Heritage Buildings
Part VI
comfortable controlled indoor environment from the weather outside.
To maintain our indoor environment,
the envelope must control the flow of
heat, air and moisture from the inside of
the home to the outdoors.
The Envelope and Heat Flow
As part of the controlled indoor environment, we add a heating system to overcome the cold Canadian winters. We try
to build our homes so that we don’t heat
the Great Canadian Outdoors. We try to
keep the heat in!
But heat will move wherever there is a
difference in temperature. Basically,
heat flows from areas of warmth to
areas of cold.
Many people believe that because hot
air rises, most heat loss will be through
the ceiling. This is not necessarily so.
Heat moves in any direction – up,
down or sideways – as long as it is moving from a warm spot to a colder one. A
heated room over an unheated garage
will lose heat through the floor.
Similarly, heat loss can occur through
walls in the basement or crawl space, as
well as above the ground. Heat moves to
the cold. It’s the envelope’s job to control
the flow of heat between the indoors
and outdoors.
Heat moves out of the house in
all directions.
How Does Heat Flow?
Heat flows in three distinct ways. In a
part of the house envelope, such as a
wall, heat can be moving in one, two or
three ways at the same time.
Conduction. Heat can be transferred
directly from one part of an object to
another part by the particles bumping
into each other. For example, the heat
from a cast iron frying pan is transferred to the handle and eventually
to your hand. Some materials conduct heat better than others, depending on the structure of the material.
Insulation works by reducing heat
flow with tiny pockets of air, which
are relatively poor conductors of heat.
Keeping the Heat In 1 How Your House Works
Heat can move by conduction, convection and radiation.
Convection. Heat can also be transferred by the movement of a fluid
such as water or air. In an uninsulated wall space, for instance, air
picks up heat from the warm wall
and then circulates to the cold wall
where it loses the heat. Some heat is
also transferred by the mixing of
warm and cold air.
Radiation. Any object will radiate
heat in the same way that the sun
radiates heat. When you stand in
front of a cold window, you radiate
heat to the window and so you feel
cold, even though the room temperature may be high.
The Envelope and Airflow
Uncontrolled airflow through the envelope can be a major source of heat loss
and can lead to other problems. Since
warm air can carry large amounts of
water vapour, airflow is also the main
means by which moisture is carried into
the envelope.
Under winter conditions, air is forced
through the building envelope. Air moving out carries heat and moisture, while
air moving in brings uncomfortable
drafts and dry winter air.
Stack Effect. In a heated home,
the less dense warm air rises and
expands, creating a higher-pressure
area near the top of the house. Air
escapes through holes in the ceiling
and cracks around upper-storey
windows. The force of the rising
air creates lower pressure near the
bottom of the house, and outside air
rushes in through cracks and openings around the lower floors.
Combustion and Ventilation Effect.
Appliances that burn fuels such as
wood, oil or natural gas need air to
support combustion and provide the
draft in the chimney. Open chimneys
and fireplaces tend to exhaust lots of
air. This air must be replaced, and
outside air will be drawn in through
the envelope. This is why people often
notice that the room becomes drafty
when there’s a fire in the fireplace.
For air to move from one side to the
other, there must be a hole in the envelope and a difference in air pressure
between the inside and outside. The difference in air pressure can be caused by
any combination of:
• wind;
• a temperature difference creating a
“stack effect” in the home; and
• combustion appliances or exhaust
Wind Effect. When wind blows
against the house, it creates a highpressure area on the windward side,
and air is forced into the house.
There is a low-pressure area on the
leeward side (and sometimes other
sides) where air is forced out.
Ventilation fans in the kitchen and bathroom, central vacuum systems, stovetop grills, clothes dryers and other
exhaust fans also cause this effect.
Keeping the Heat In 1 How Your House Works
Wind effect
The Envelope and Moisture
Moisture can cause concrete to crumble,
wood to rot and paint to peel; it can
also damage plaster and ruin carpets.
In its many forms, moisture is a
major cause of damage to building
Moisture can appear in the form of a
solid, a liquid or a gas (water vapour).
Moisture can originate from outside as
ground water in the soil or as ice, snow,
rain, fog and surface run-off, or from
inside in the form of water vapour produced by the house occupants and their
activities, such as washing, cleaning,
cooking and using humidifiers.
In its different forms, moisture can
move through the envelope in a number
of ways.
Stack effect
Combustion and ventilation effect
Gravity. Water running down a roof
or condensation running down a
window pane shows how gravity
causes water to move downward.
Capillary Action. Water can also
move sideways or upward by capillary
action. Capillary action depends on
the presence of very narrow spaces, as
with lapped siding or porous materials such as concrete or soil (think of
how a paper towel absorbs water).
Far more moisture can be carried by
airflow through a small hole in the
envelope than by diffusion through the
building materials.
Diffusion. Water vapour can also
move directly through materials by
diffusion. Diffusion depends on a
difference in water-vapour pressure
and the material’s resistance to this
Air Movement. As water vapour,
moisture is carried by moving air, for
example, where there is air leakage
through a crack in the house envelope.
Water vapour becomes a problem when
it condenses into liquid water. This
happens at the point of 100 percent
relative humidity, when the air cannot
hold more water vapour.
A typical example is condensation on
windows. When the air contacts the
cold window it loses heat. Since the air
has become cooler, it can no longer
hold all the water vapour, and some
condenses out onto the surface of
the window.
Keeping the Heat In 1 How Your House Works
One small air leak can let through 100 times as much
moisture as will travel by diffusion over a much larger area.
If the window is extremely cold, the condensation will appear as frost. Because
the interior surface of a single-glazed
window is colder than that of a doubleglazed window, a single-glazed window is
more likely to have problems with condensation or frost buildup, even under
conditions of lower humidity.
Condensation is more likely to occur in
humid areas of the house such as the
kitchen and bathroom.
The House as a System
Although this book concentrates on
improvements to the house envelope, it’s
important to remember that the house
operates as a system. All the elements of
a house, the environment, envelope,
mechanical systems and occupant
activities affect each other, and the result
Condensation occurs when moist air meets a cool surface.
affects the performance of the house as a
whole. Understanding these relationships is the secret to avoiding problems.
For example, reducing air leakage
makes the house more comfortable and
protects the envelope from moisture
damage. But it will also increase humidity levels since less water vapour
escapes. This can mean an increase of
condensation on windows.
The lesson here is that a change to one
component of the house can have an
immediate effect on another component. The combined effect of many
small changes over time can also affect
the balance of the system.
Before beginning any retrofit work, it’s a
good idea to review what’s involved and
to understand which other aspects of
the house may be affected. Thinking
things through and careful planning in
the early stages of work will prevent
unpleasant surprises and ensure that the
work meets your expectations.
Further information on the effect that
retrofit work has on the house as a system is included in the balance of this
chapter and in Chapters 3 and 8. If you
have any questions, talk to an expert or
a contractor who is familiar with the principles of how a house works as a system.
Keeping the Heat In 1 How Your House Works
Metric Conversion
Uninsulated wall
Insulated wall
to obtain
RSI value overall
R-value overall
1 R/in.
Nominal RSI Value
Nominal R-Value
Insulation works by trapping small pockets of air.
What Does
Insulation Do?
Insulation is like a giant
sleeping bag. It wraps
the house in a layer of
material that slows the rate at which
heat is lost to the great outdoors.
Remember that heat always flows from
warm to cold, and it moves in three
ways: by conduction, convection or
Still air does not conduct heat well and
is a relatively good insulator. However,
in large spaces such as wall cavities, heat
can still be lost across the air space by
convection and radiation. Insulation
divides the air space into many small
pockets of still air; this inhibits heat
transfer by convection. At the same
time, the insulation material reduces
radiation across the space.
What Is the Insulation Value?
Years ago when the choice of insulation
was limited, the measure of the effectiveness was its thickness. Products have
changed and that rule of thumb can no
longer be applied.
Insulation is now manufactured and
sold by its thermal resistance value
(called the “RSI” value) – a precise
measurement of the insulation’s
resistance to heat flow. The higher
the resistance value, the slower the
rate of heat transfer through the
insulating material.
Measuring Up
Throughout this book, we have used metric
measurements and values and given the
imperial equivalent in parentheses, e.g., RSI
3.5 (R-20). We have used certain measurements as expressions, for example, a
38 mm x 89 mm stud is what we commonly
know as a 2 x 4. In these cases, we have
chosen not to include the unit of measurement. Imperial equivalents are included
because most retrofit projects take place in
houses that were built using this system of
One brand of insulation may be thicker
or thinner than another, but if they both
have the same RSI value, they will control heat flow equally well. Chapter 2
describes insulation materials and their
RSI values.
Keeping the Heat In 1 How Your House Works
Some insulation materials are marked
with both RSI and R-values. RSI values
indicate thermal resistance in metric
terms (Resistance Système International),
and R-values represent imperial measurements. Be careful not to confuse
the two.
For insulation to work properly, it must
be installed properly. Chapters 4, 5 and
6 describe how to install insulation in
attics, basements and walls. There are
some common guidelines, however, that
apply wherever insulation is installed.
• The insulation must fill the space
completely and evenly. Any blank
spots or corners will allow convection
to occur, sometimes allowing the heat
to bypass the insulation completely.
• Wherever possible, avoid thermal
bridges. As the name suggests, a thermal bridge is any solid material that
directly connects the warm side of
the envelope to the cold side (e.g., a
wall stud). Steel studs, for example,
are very conductive and can reduce
the effective wall insulation by 50
percent. When insulation is installed
on one side of the thermal bridge, it
acts like a roadblock, reducing heat
• It is also important to install the
appropriate thickness of insulation for
the size of the space and, when using
loose fill, at the proper density.
How Much Insulation?
Your choice of how much insulation to
add will depend on many factors:
• Local housing codes may specify
minimum levels of insulation that
should be added when upgrading.
• How much insulation is already in
the house will partly determine how
much you need to add.
• How the house is built will determine how much insulation may be
practically added.
• Other work you are doing together
with the re-insulating may make it
practical to add higher levels of insulation.
The table on the right is a good guideline to follow to determine insulation
levels for different areas of a house. To
help you make your decision, you may
wish to compare your plans with the
Model National Energy Code for Houses
for your province or territory.
Wood studs provide a thermal
bridge and gaps in the insulation
allow convection currents.
The thermal resistance values listed in
the code are more accurate than the
ones listed in the table at right because
they take into account the type of framing and heat loss through the framing
materials. You can also obtain information about the recommended minimum
levels of insulation that correspond to
your home’s method of construction,
region and heating fuel type. Write to:
Natural Resources Canada
Housing and Equipment Division
580 Booth Street, 18th Floor
Ottawa ON K1A 0E4
Fax: 613-996-3764
Web site: ecoaction.gc.ca
Keeping the Heat In 1 How Your House Works
Degree-Day (DD) Zones
up to 3500 DD
3500 – 5000 DD
5000 – 6500 DD
over 6500 DD
Note: Each zone on the map represents an area that experiences a similar number of
degree-days. Degree-days are a measure of heating demand based on the difference
between the average daily outdoor temperature and 18°C (65°F). Cumulative totals for the
month or heating season are used to estimate heating energy needs.
Roof or
Floor (over
Keeping the Heat In 1 How Your House Works
Why Control
Controlling airflow
provides many benefits:
• greater energy and dollar savings;
• a more comfortable home without
cold spots and drafts;
• protection of the building materials
from moisture damage;
• improved comfort, health and safety:
stale odours and stuffiness are eliminated, and a safe supply of air for
combustion appliances is assured; and
• a cleaner and quieter home.
Controlling airflow involves three
relatively simple activities:
• preventing uncontrolled air leakage
through the building envelope;
• providing for fresh-air supply and the
exhaust of stale air; and
• providing draft and combustion air
for fuel-burning appliances.
The important point is that these
activities must always be done together.
Halfway measures will not do.
Air-Leakage Control:
Wind Barriers, Air Barriers and
Air Sealing
To be effective, insulation must trap
still air. It must be protected from wind
blowing through from the outside and
from air escaping from the inside of
the home.
The wind barrier is located on the outside of the envelope to protect the insulation from the circulation of outside air.
Standard building materials such as
exterior sheathing and building paper
or new sheet materials such as housewraps act as the exterior wind barrier.
The air barrier blocks airflow from the
inside to the outside. By doing this, it
serves the following two important
• It reduces heat loss by preventing air
from passing in and out through the
• It protects the insulation and structure from moisture damage caused
when water vapour condenses in the
envelope assembly.
The air barrier can be installed at any
location in the envelope; it may even be
combined with the wind barrier. It’s
usually installed on the inside of the
envelope where it is kept warm. This
protects the material from temperature
extremes that can affect its durability.
When installed on the warm side, the
air barrier is often combined with the
vapour barrier. (See the section on
vapour barriers on page 20.) If located
on the inside, the air barrier will also
prevent convective heat loss when air
circulates from the house into the
wall space.
Keeping the Heat In 1 How Your House Works
The air barrier is a
system that joins
many different
To make sure that you’ve accounted for a continuous air barrier, make a sketch of the wall, attic or
foundation that you plan to retrofit. Then take a coloured pencil and trace a line through all the air
barrier components on the sketch without lifting the pencil from the paper.
different components that are sealed to
each other. Typical components of the
air-barrier system are described below.
• Polyethylene, drywall or plaster are
used for large surfaces such as walls
and ceilings.
• Windows, doors, hatches, vent
dampers and any components that
close an opening in the envelope also
form part of the air barrier.
To be effective, the air barrier must be
the following:
• resistant to air movement;
• rigid and strong enough to withstand
air-pressure differences;
• durable; and
• continuous, by sealing all seams,
edges, gaps, holes or tears.
Because of the many components that
make up the house envelope, including
walls, foundations, doors and windows,
it’s impossible for any one material to
surround the house completely and
form the air barrier. The air barrier is
actually a system made up of many
• In some cases, even structural parts
of the building, such as the sill
plate or rim joist, form part of the
air-barrier system.
• Caulking, gaskets and weatherstripping are used to seal the joints between
the components to ensure that the
air-barrier system is continuous.
How Tight an Air Barrier?
For an air barrier to work, it must be
continuous and well sealed.
But if the air barrier is tight, how will
fresh air get into the house? First, most
older houses are so loosely built that,
even after extensive air-leakage-control
work, enough air will still come in to
provide ventilation. Second, remember
that the air barrier is just the first step in
the control of airflow. The other essential steps are providing ventilation air
and air for combustion in a controlled
manner. These steps may be necessary
in houses where extensive retrofit and
renovation work has been done, where
the house is heated with a reduced flueaction heating system (e.g., electricity or
a high-efficiency gas system) or where
there are special ventilation needs. It is a
good idea to take a systematic look at
the moisture balance and ventilation
needs of your house.
Providing Controlled Ventilation
Years ago, homes were ventilated by
opening windows and doors and by
uncontrolled air movement, but this
method was not always comfortable or
effective. In cold, windy weather, too
much air could be drawn into the
house, causing high fuel bills and
uncomfortable drafts. Often, in spring
and fall, not enough fresh air would be
With uncontrolled airflow stopped by
an air-barrier system, it is now possible
to provide comfortable, effective ventilation year-round.
Keeping the Heat In 1 How Your House Works
A system for controlled ventilation consists of four basic parts:
• a means of exhausting stale air and
excess water vapour;
• a means of supplying fresh air;
• a way of distributing the fresh air
throughout the house; and
• controls for operating the ventilation
Many homes already have parts of a
complete ventilation system; it’s just a
matter of putting it all together and
adding the missing components.
The exhaust function can be provided
by kitchen and bathroom fans; these are
already located conveniently in areas of
high humidity. Clothes dryers should
also be vented outdoors.
Fresh air supply can be arranged for
homes with a forced-air heating system
by installing an outside duct connected
to the forced-air system. Air is distributed
by running the furnace fan on low speed,
even when the furnace is not heating.
Houses can have many ways of providing ventilation:
1) bathroom fan
5) duct to return-air plenum
2) open window
6) central ventilation system
3) kitchen fan
7) holes in the envelope
4) exhaust or supply fan
In homes with individual room heaters,
fresh air can be provided by installing a
central supply with a duct to each room
and a fan to move the air. This system is
easiest to install in bungalows. In colder
regions, the incoming air may need to
be tempered or preheated.
Controls are usually connected to the
exhaust side of the system; the supply
side responds passively to replace the
amount of air exhausted. One control
method uses humidity as an indicator of
how much air needs to be exhausted.
There is usually an automatic setting on
the exhaust fan for routine operation,
with a manual override for cooking,
showers or times when there are more
people in the house.
Keeping the Heat In 1 How Your House Works
Providing Air for Combustion
A combustion appliance is any device
that burns fuel; furnaces, fireplaces,
woodstoves, gas stoves, gas water heaters
and gas dryers are all combustion appliances. Combustion appliances require
air to burn the fuel and to provide draft
for the appliance’s chimney.
Fuel-burning appliances and exhausting appliances all need make-up air.
How Much Ventilation?
Recognizing that homes are now built
with tighter air barriers, the National
Building Code of Canada now requires
that new homes include a mechanical
ventilation system with a minimum
exhaust capacity of one third of an air
change per hour. This means that one
third of the total volume of air in the
home is replaced by outside air every
Not every home where retrofit work has
been done will need this much mechanical ventilation capacity. Even after
extensive air-sealing work, most older
houses still allow considerable airflow
through the envelope. Humidity levels
and the appearance of condensation can
provide a rule of thumb for judging ventilation needs. Generally, if there is only
occasional or a small mist of condensation on double-glazed windows on the
coldest days, then sufficient ventilation
is present. Of course, houses where there
is little moisture generated but in which
there are pollutants due to hobbies,
smokers, etc., will require more ventilation. The tightness of the air-barrier system can be assessed using a fan test.
(See Chapter 8 for more information on
ventilation strategies.)
Older homes without a tight air barrier
typically provide plenty of air combustion and draft control through cracks
and holes in the building envelope.
Tighter houses and houses in which
fans, exhaust appliances and fireplaces
may be competing for air can experience
insufficient draft and even backdrafts.
This can be a serious safety consideration where the draft in the chimney can
be reversed, and dangerous combustion
gases can spill back into the house.
As part of any air-leakage-control program, it’s important to ensure that each
combustion appliance has enough air to
work properly. Chapter 8 provides more
detail on combustion-air strategies.
Keeping the Heat In 1 How Your House Works
Quantity of Moisture Added to the Air Through Various Household Activities
Activity (for a family of four)
(litres per week)
Cooking – three meals daily for one week
Dishwashing – three times daily for one week
Bathing – 0.2 litres per shower
– 0.05 litres per bath
Clothes washing (per week)
Clothes drying indoors or using an unvented dryer (per week)
Floor mopping per 9.3 m (100 sq. ft.)
Normal respiration and skin evaporation from occupants
Total moisture production per week
Why Control
Moisture Flow?
Control of moisture in
all its forms is important
in order to make our homes
durable and comfortable. Building components and practices such as flashing,
roofing and basement damp-proofing
successfully protect the home from
liquid water.
It is equally important to control the
movement of water vapour, providing
added protection for the house structure
and helping to maintain indoor humidity at a comfortable level.
Controlling moisture involves the
following three strategies:
• construction techniques that keep
moisture away from the structure;
• producing less moisture; and
• exhausting excess moisture.
Sources of Moisture in the Home
Even some houses that are apparently
dry, with no leaks in the basement or
roof, can have moisture problems.
Where does all the moisture come from?
There are a number of major sources
that are not always obvious:
• occupants and their activities;
• wind-blown rain in walls;
• damp basements; and
• moisture that is stored in building
materials and furnishings.
An average family of four will generate
about 63 litres (20 gallons) of water a
week through normal household activities. Where basement damp-proofing is
inadequate, ground water in the soil can
migrate through the foundation by
capillary action and evaporate on the
surface of the wall or floor. Finally, during damp, humid weather, the building
materials and furnishings will absorb
moisture from the air, and then expel it
during the heating season.
Despite all this water produced each
day, most older houses have “dry” air in
winter to the point where they have to
have humidifiers installed. Why?
Cold outdoor air cannot carry much
water vapour. In older homes, uncontrolled airflow brings colder, drier air
indoors and forces the warm, moist
household air out through openings in
the upper walls and attic. The air
quickly escapes through the uninsulated
envelope without cooling down enough
to cause condensation.
When insulation is added, the building
exterior becomes much colder. Unless
additional protection is provided, water
can condense in the building structure.
How? Remember that cold air is able to
hold much less moisture than warm air.
As the warm, moist air cools in the cold
outer layers of the building, the water
vapour it holds may condense as liquid
or, if it is cold enough, as frost. This can
reduce the effectiveness of insulation
and even cause rot, peeling paint,
buckled siding, mould growth and
other problems.
Keeping the Heat In 1 How Your House Works
Water vapour condenses as either
liquid water or frost when it
reaches the dew point.
How Much Humidity?
Humidity levels above 20 percent help
prevent dry, sore throats and should
make the air feel warmer and more
comfortable. Moist air will also eliminate static electricity in the house and
help to protect plants and preserve
your furniture.
On the other hand, humidity levels over
40 percent can cause frosting and fogging of windows, staining of walls and
ceilings, peeling paint, mould growth
and odours. When relative humidity is
over 50 percent, airborne diseases
become more difficult to control.
Condensation on your windows can
provide a good indication of the relative
humidity. You may, however, want to
install a humidity sensor or humidistat
to keep more accurate measurements on
humidity levels.
Keeping the Structure Dry
Four strategies are used to keep the
structure dry.
The building envelope must shed water from the roof to the footings.
1. Exterior weather and moisture
protection requires building paper,
siding, flashing, gutters and other construction techniques to shed water and
repel wind-driven rain. It also involves
below-grade measures such as proper
drainage, grade slope and damp-proofing to protect the foundation from
ground-water leaks or from moisture
movement by capillary action.
2. Reducing moisture at the source
involves producing less moisture in the
first place and exhausting moist air and
bringing in drier air. Detailed strategies
are outlined in Chapter 8.
Keeping the Heat In 1 How Your House Works
3. Preventing moist indoor air from
getting into the envelope requires
a vapour barrier to reduce moisture
movement by diffusion and an air
barrier to prevent moisture movement
by air leakage.
properly installed. Polyethylene sheets
and foil-backed gypsum drywall can
both combine these functions. To avoid
confusion of terms, when a material is
doing both jobs it will be called an air
and vapour barrier.
Air barriers are described on pages
14 to 17. Although less moisture can
be moved into the envelope by vapour
diffusion, it is still important to provide
a vapour barrier. An effective vapour
barrier must be the following:
As a general rule, the vapour barrier
should be on the warm side of the insulation. In some cases, however, the
vapour barrier can be located within the
wall or ceiling assembly, provided that at
least two thirds of the insulation value
of the wall is on the cold side of the
vapour barrier. Because this ratio should
be adjusted for houses with high interior
humidity or for homes in extremely cold
climates, it is recommended that you
consult a professional builder-renovator,
who will apply the specifications outlined in the National Building Code of
• resistant to vapour diffusion;
• durable;
• installed on the warm side of the
insulation; and
• not necessarily continuous.
A number of building materials resist
vapour diffusion well enough to be
used as vapour barriers. These include
polyethylene, oil-based paints and
special vapour-barrier paints, some
insulation materials and exterior-grade
plywood. Different materials may act as
the vapour barrier in different parts of
the house.
The same material may work as both an
air barrier and a vapour barrier, provided it meets both requirements and is
4. Letting the envelope “breathe” to
the outside allows the house to deal
with seasonal fluctuations in humidity
and to release any moisture that does
penetrate the envelope from the interior
or exterior. This is accomplished in two
ways. The materials of the envelope are
layered, with those most resistant to
vapour diffusion located on the warm
side of the envelope and the least resistant (such as building paper) located on
Up to one third of the insulating
value can be installed on the
warm side of the vapour barrier.
the outside. In this way, any vapour that
penetrates the envelope can escape to
the outside.
Some wall systems work well with a relatively impermeable insulated sheathing
because the interior wall-cavity temperatures are kept high. As a precaution,
when retrofitting a wall, always ensure
that the interior surfaces are vapourresistant.
Some siding applications have an air
space immediately behind the exterior
finish to promote drying out of materials that have been soaked by rain or
dampness. This air space also provides
an escape route for any moisture that
has penetrated the wall cavity from the
indoors. This type of installation should
not be used with insulated siding as
convection in the air space will negate
the effect of the insulated backer board
on the siding.
Keeping the Heat In 1 How Your House Works
The examples given in
this chapter highlight
the need to consider
the house as a system
when planning any
retrofit work. Pay special attention to
the air and moisture balance and the
effect of the retrofit on the heating system and ventilation.
Further information on the house as a
system is included throughout this
book. Later chapters describing how
to insulate your home also include
recommended methods for controlling
air and moisture in walls, basements
and attics. Chapter 3, “Comprehensive
Air-Leakage Control”, includes
strategies for moisture control, and
Chapter 8, “Operating Your House”,
describes strategies for providing
ventilation and combustion air.
For major retrofit projects, you may
have to anticipate the need for changes
to the heating system or house ventilation and include these changes in the
work plan. When undertaking smaller
projects that are spread out over time,
monitor your house carefully after each
project to assess the impact of the
changes. At some point, adjustments
to the heating system and house ventilation will likely be essential to keep the
system working properly.
Keeping the Heat In 1 How Your House Works
Whether your home is
50, 75 or 100 years old,
it represents a part
of our architectural
heritage. Older homes
deserve special consideration when
retrofitting. Maintaining the durability
of the structure is especially important.
Homes over 50 years old may incorporate unusual construction details and
materials that make it necessary to
improvise and adapt standard retrofit
methods. Retrofit work will need to be
done with sensitivity to the design,
materials and special features of the
home. The retrofit will need to minimize changes to the building’s appearance and emphasize repair, rather than
replacement, of building components.
Although there are bound to be some
sacrifices in energy efficiency, with a little more planning and care, you can do
a lot to make older homes more comfortable, durable and energy efficient.
Extra care at the planning stage involves
assessing the home from several aspects.
• Heritage: What features have to be
preserved? What later changes (if
any) should be removed?
• Maintenance and repair: What areas
need attention? Do any needed
repairs indicate moisture or structural
problems that should be corrected?
• Energy efficiency: What improvements can be made while maintaining the heritage quality of the
The following are some sample guidelines and opportunities for retrofit of
older homes.
Air Sealing: Comprehensive air
sealing is one of the least obvious and
most effective retrofit projects for
older homes.
Older window
Heating System: A total tune-up of
the heating system is another inexpensive, effective and invisible measure for
older homes.
Insulation: Preserving the structure is
especially important; take extra care to
provide a vapour barrier and air barrier
when insulating. Basements and attics
can often be re-insulated without affecting appearance. Where it is desirable to
preserve both the interior and exterior
wall finishes, blowing insulation into the
cavity of a wood-frame wall is an
option. Often, older homes have had the
original exterior finish replaced with a
more modern but less appropriate
Keeping the Heat In 1 How Your House Works
material. Insul-brick may have replaced
the original stucco, or permastone may
have replaced the original cement
parging. These situations provide the
opportunity to retrofit from the exterior
and, at the same time, copy the original
Windows: Windows are one of the
most important aspects of a home’s
originality. Careful weatherstripping of
older, single-pane, wood-frame windows will do much to improve their
energy efficiency. If the original wooden
storm windows have been destroyed, it’s
possible to have custom wood storms
made to order. If the object is to preserve the appearance of the building,
avoid metal storms or storm-and-screen
Doors: Preserving the original doors is
important to the overall appearance of
an older home. Careful weatherstripping
will improve their performance. As
with windows, avoid aluminum storms.
A better alternative is to restore the
enclosed vestibule that is found in most
older homes.
If exterior wood storms are not desirable
because of the maintenance factor,
interior storms offer a good alternative.
These are less noticeable than exterior
metal storms, and they can be made to
fit on the sash or the window trim. If
the window sash is badly deteriorated,
replacement units can be made to fit the
existing frame.
2 Materials
Keeping the Heat In
Whether you’re doing the work yourself
or hiring a contractor, it’s important to
know what the right materials are for
your particular job. Choosing the right
materials and installing them properly
will ensure that the finished product
lives up to your expectations.
This chapter describes the three types of
materials used when keeping the heat
in: insulation, air-barrier materials and
vapour-barrier materials.
Review the chapters in this book that
deal specifically with your particular
project and use this information to
choose the most appropriate materials.
Keeping the Heat In 2 Materials
Part I
Part II
Requirements for
Insulation’s main
function is to keep the
heat in. To be effective,
insulation must be the following:
• resistant to heat flow;
• able to fill the space completely
and evenly;
• durable; and
• for some locations, able to withstand
exposure to heat or moisture.
Several different insulation materials
may be used at different locations in the
house envelope, depending on the space
available for the insulation, ease of access
and other installation requirements.
Part III
Health and Safety
Part IV
• resistance to high temperatures;
• resistance to moisture flow
(can it reduce the movement of
water vapour?);
• resistance to air movement (can it
act as an air barrier?); and
• when required, a fire-rated protective
Once you have matched the material
properties with the specific application,
consider the following installation factors:
• Is it relatively easy to install?
• Is it the best buy for the space available (either high insulating value per
dollar if you have lots of open space,
or high insulating value per thickness
if space is restricted)?
• Is it available locally?
• Will it be easy to install the insulation to fill the space completely?
The Proper Choice of Insulation
• Can it conform to surface irregularities?
The proper choice of insulation depends
on its final use. In most applications,
good resistance to heat flow is not the
only thing you will have to consider. In
specific situations, insulation may also
need to have any number of the following properties:
• Is it rigid enough to provide support
for finished materials or resist pressures against its surfaces?
Special Health
Part V
• Does one insulation require more
accessory products than another
(fire protection, framing, air and
vapour barrier)?
In short, the choice of insulation will
largely depend on how it will be used.
The chapters on insulating walls, basements and attics discuss the types of
insulation commonly used for these
applications. Fortunately, particular
insulation jobs will quickly eliminate
some materials, making the choice
much easier.
Naturally, cost is a factor in the choice
of material. Generally, the cost per RSI
value is lower for loose-fill or batt-type
materials than for rigid board or foamtype insulations. However, the price of
the basic material is just one aspect. In
some cases, high material costs may be
offset by lower installation costs or the
preference of the installer for a particular insulation technique. A better comparison can be made using the installed
cost. This includes the cost of the insulation material plus the cost of required
accessories and installation.
Keeping the Heat In 2 Materials
Batt insulation
Insulations are manufactured from a
wide range of materials, including
melted glass spun into fibres, expanded
volcanic rock, recycled newsprint and
foam plastic.
However, there are only four basic
forms of insulation that provide a ready
means of classification: batt or blankets,
loose-fill insulation, rigid or semi-rigid
boards, and spray-foam insulation. The
following are detailed descriptions of all
these categories.
Blown-in insulation
Summary of Insulation Types
• Will not settle.
Batt or Blanket Insulation
• Some products are non-combustible
(check with the manufacturer).
Batt or blanket insulation is relatively
easy to install in accessible spaces such
as exposed wall cavities and some attics.
It conforms to slight surface irregularities and can be cut to fit. Safety
equipment and protective clothing
are required during installation.
Mineral Fibre
• Includes 0.022 RSI/mm (3.2 R/in.)
glass fibre.
• Includes 0.023 RSI/mm (3.3 R/in.)
mineral wool.
• Is available in batts or continuous
rolls (blankets).
Loose-Fill Insulation
Loose-fill insulation is made from a
variety of materials, with particles ranging in texture from granular to fluffy.
Loose-fill insulation is excellent for filling irregular or inaccessible spaces. It is
suitable for walls and floors and excellent in attics and enclosed spaces such as
roofs where the space between the joists
may be irregular or cluttered with obstacles. It is often handy for filling small
spaces or covering ceiling joists. It is not
appropriate for below-grade application.
Keeping the Heat In 2 Materials
Note: Unless otherwise indicated, all the insulation materials listed require the presence of
an air barrier and a vapour barrier.
• Because of its small particle size, can
fill around obstructions such as nails
or electrical wires within cavities.
• May reduce air leakage if installed to
the proper densities.
• Average RSI of 0.025/mm (3.6 R/in.),
depending on the paper and chemical mix and the blown density.
• Proper blown density for enclosed
cavities is 56 to 72 kg/m3
(3 1⁄2 to 4 1⁄2 lb./cu.ft.).
• Insulating value of 0.024 RSI/mm
(3.4 R/in.).
Loose-fill insulation
Loose-fill insulation may be blown or
poured. Pouring insulation will generally require more material than blowing
insulation to achieve a specified RSI
value. It is useful for topping up existing
insulation in attics and accessible
enclosed wall cavities and for filling in
cracks and uneven spaces.
The proper installation of blown loosefill insulation usually requires an experienced, well-trained technician. To
achieve the full RSI value, the material
must be installed following the manufacturer’s instructions.
Safety equipment and protective clothing are required during installation.
The most important aspect of installation is following the manufacturer’s
• Follow manufacturer’s instructions
for proper application techniques.
Glass Fibre
• A similar material to glass-fibre batts,
but chopped up for blowing or pouring applications.
Cellulose Fibre
• Made from shredded newsprint
treated with chemicals that resist fire
and fungal growth and inhibit
Keeping the Heat In 2 Materials
• Hand-poured glass fibre works best
in open horizontal surfaces such as
attics. Blown glass fibre can be used
in both horizontal and vertical
applications, but may be difficult to
install in cavities that are partially
blocked by nails, framing, electrical
wiring, etc.
• For walls, the density of application
is usually two to two and a half times
the recommended rate of application
for horizontal surfaces.
• Some classified as non-combustible.
Check the manufacturer’s specifications.
• Average insulating value of 0.020
RSI/mm (2.9 R/in.), depending
on density.
• Follow manufacturer’s instructions
for proper application techniques.
• Insulating value of 0.021 RSI/mm
(3.0 R/in.).
• Follow manufacturer’s instructions
for proper application techniques.
Rigid board insulation
Mineral Wool (Slag and Rock Wool)
• Treated with oil and binders to suppress dust and maintain shape; a
lubricant is added for blowing purposes. Similar to glass fibre in
appearance and texture.
• Suitable for accessible attics and inaccessible areas such as wood-frame
roofs, walls and floors.
• For walls, the density of application is
usually two to two and a half times
the recommended rate of application
for horizontal surfaces.
• Good for insulating around masonry
chimneys as it will not support combustion.
• Average insulating value of 0.021
RSI/mm (3.0 R/in.), depending on
the density at which it is blown in.
• Follow manufacturer’s instructions
for proper application techniques.
• Insulating value of 0.022 RSI/mm
(3.2 R/in.).
• Follow manufacturer’s instructions
for proper application techniques.
• An expanded mica material that was
commonly used in older homes,
although less readily available these
Keeping the Heat In 2 Materials
Warning: Some vermiculite insulation may
contain asbestos fibres. From the 1920s to
1990, a vermiculite ore produced by the Libby
Mine in Montana, USA may have contained
asbestos. It was sold in Canada as Zonolite®
Attic Insulation and possibly as other brands.
Not all vermiculite insulation produced before
1990 contains asbestos fibres. However, to be
safe in the absence of evidence to the contrary, it is reasonable to assume that if your
home has older vermiculite insulation, it may
contain some asbestos.
If vermiculite is contained in walls or attic
spaces and is not disturbed, it poses very little
risk to occupant health. However, if it is
exposed or disturbed as it might be during a
renovation, it can cause health risks. Asbestos
inhalation is associated with asbestosis, lung
cancer and mesothelioma.
If you find older vermiculite insulation in your
home, do not disturb it and consult the Health
Canada publication "It’s Your Health –
Vermiculite Insulation Containing Asbestos"
available free by calling 1-800-O-Canada, or
visit www.hc-sc.gc.ca.
• Two types – untreated and treated.
Untreated vermiculite absorbs moisture. Treated (water-repellant) vermiculite is coated with asphalt for use
in areas of high moisture.
• Untreated vermiculite has an average
insulating value of 0.016 RSI/mm
(2.3 R/in.); treated vermiculite has
an average insulating value of 0.017
RSI/mm (2.5 R/in.).
• Usually hand-installed.
• Suitable for both horizontal and
vertical applications.
• For vertical applications, it is poured
into the wall cavity and packed down
with a heavy weight to make sure
that the cavity is filled and to prevent
future settling.
• Follow manufacturer’s instructions
for the proper application techniques.
Rigid Board Insulation
Board insulations are manufactured
from glass fibre or foam plastic materials.
These materials have a high insulating
value per unit thickness, although the
cost per RSI value is greater than for
loose-fill or batt/blanket insulations.
Insulating boards are lightweight and
easy to cut and handle. Fitting them
into irregular spaces, however, can be a
tedious process. Some boards are now
available with an attached fire-resistant,
moisture-resistant or decorative covering. It is also possible to purchase
specially designed boards that come
with their own system of attachment.
Regular board materials can be
ordered pre-cut to specific sizes for an
additional cost.
Glass-Fibre Boards
• Two types of high-density, semi-rigid
glass-fibre board are commonly used
in residential applications: one
designed specifically for below-grade
exterior use, and the other an abovegrade exterior sheathing.
• Above-grade type covered with a
water-repellent breather-type building paper.
• Below-grade type has an insulating
value of 0.029 RSI/mm (4.2 R/in.).
• The exterior sheathing has an
insulating value of 0.031 RSI/mm
(4.4 R/in.).
Expanded Polystyrene
• Produced by bonding coarse beads
into rigid foam plastic boards. It is
often referred to as “bead board.”
• Manufactured in the following two
– low density with an insulating
value of 0.026 RSI/mm
(3.7 R/in.); and
– high density with an insulating
value of 0.028 RSI/mm
(4.0 R/in.).
• High-density board is more resistant
to moisture than low-density board
and can be used on the exterior of
foundation walls in dry, sandy soils.
• Must be protected from prolonged
exposure to sunlight, solvents and
some sealants. Use compatible
sealants only. Ask your dealer for
• Requires covering with a fire-resistant
Extruded Polystyrene
• A foam plastic board with fine,
closed cells containing a mixture of
air and refrigerant gases (fluorocarbons).
Keeping the Heat In 2 Materials
• Manufactured in the following two
– low density with an insulating
value from 0.033 RSI/mm
(4.7 R/in.) to 0.035 RSI/mm
(5.0 R/in.); and
– high density with an insulating
value of 0.035 RSI/mm (5.0 R/in.).
• Must be protected from prolonged
exposure to sunlight or solvents.
• If joints are sealed properly, can perform as an air barrier, and certain
thicknesses may perform as a vapour
• When installed on interior surfaces,
must be covered with a fire-resistant
material that is mechanically fastened
to the building structure.
Polyurethane and Polyisocyanurate
• Plastic boards made of closed cells
containing refrigerant gases (fluorocarbons) instead of air.
• Usually come double-faced with foil
or are sometimes bonded with an
interior or exterior finishing material.
• Suitable for areas where space is at a
premium but high RSI values are
• Faced boards have a typical insulating
value of 0.040 RSI/mm (5.8 R/in.)
to 0.050 RSI/mm (7.2 R/in.) and
come in a variety of sizes.
• Typical insulating value of 0.030
RSI/mm (4.3 R/in.) open cell and
0.058 RSI/mm (8.3 R/in.) closed cell
(based on manufacturer’s literature).
• Must be protected from prolonged
exposure to sunlight and water.
• Must be protected from exposure to
sunlight and water.
• Must be covered with a fire-resistant
Spray-Foam Insulation
• Can act as an air barrier (if seams are
well sealed) and as a vapour barrier.
• Use generally limited to areas where a
high RSI is desired and space is at a
Phenolic Foam Boards
• Manufactured from phenol
formaldehyde resin. Some panels
have a water-repellant exterior skin
on both sides.
This type of insulation is mixed on the
job site by the contractor or installer.
The liquid foam is sprayed directly
onto the building surface or poured into
enclosed cavities using a spray gun
driven by a pump. The foam expands in
place and sets in seconds. The installation contractor should be trained in the
application of the specific product.
Polyurethane Foam
• A pale yellow foam of closed cells
containing refrigerant gases (fluorocarbons).
Keeping the Heat In 2 Materials
• Typical insulating value of 0.042
RSI/mm (6.0 R/in.). Other values
are sometimes quoted, but this value
takes into account the loss of refrigerant gases over time.
Semi-Flexible Isocyanurate Plastic Foam
• Sprayed onto surfaces in layers less
than 50 mm (2 in.) thick and hardens in seconds.
• Manufacturers’ literature lists
insulating value as 0.030 RSI/mm
(4.3 R/in.).
• Can expand up to 28 times its original size and should not be used in
enclosed cavities.
• Some limitations on the thickness
that can be applied.
• Can be used as an air barrier but not
as a vapour barrier.
• A combination of isocyanurate,
resins and catalysts forms this
open-celled, semi-flexible plastic
foam insulation.
• Can be used as an air barrier.
• Requires covering with a fire-resistant
• Must be protected from prolonged
exposure to sunlight and requires
covering with a fire-resistant material
when used indoors.
Keeping the Heat In 2 Materials
Requirements for
Air-Barrier Systems
The air-barrier system
is an important part of
any retrofit job. It is the
main means of protecting the building
structure and the insulation from moisture damage. In order to be effective,
the air-barrier system must be the
• resistant to air movement;
• continuous, completely surrounding
the envelope of the house and properly supported by rigid surfaces on
both the interior and exterior (to prevent movement in high winds); and
• strong and durable.
A variety of materials are used throughout the envelope to act as the air barrier.
In some cases, building materials such
as drywall, baseboards or structural
members are incorporated into the air
barrier by sealing them to adjoining
Air-Barrier System Components
The most common components of an
air-barrier system are the following:
• sheet or rigid materials for large
• caulking and gaskets for joints
between materials that do not
move; and
• weatherstripping for joints that
do move.
Choosing Air-Barrier Materials
If the material offers resistance to airflow, strength and durability, consider
the following installation factors:
• Is it easy to install?
• If installed in a concealed location,
will it last the life of the building or
will it be accessible and easily
• Is it compatible with other materials
in the system? Can it be successfully
sealed to adjacent materials?
• Is the choice of material appropriate
for the other work being done on the
home? Some renovation work will
permit the installation of a new
sheet-material air barrier, while other
jobs may require comprehensive airsealing work instead.
• Does it serve other functions such
as acting as insulation or as a vapour
Sheet Materials
Polyethylene Sheeting
• Available in wide sheets, minimizing
the number of seams required.
• Seams and edges should be supported
on both sides to maintain the seal.
• A thickness of 0.15 mm (6 mil) now
commonly installed as an air barrier
because it is more durable on the
construction site.
• Should be protected from exposure
to sunlight. When exposed to sunlight over extended periods (when
wrapping the exterior of a house, for
example), a UV-stabilized polyethylene should be used.
• Should be clear, made from virgin
material and labelled. Should conform to the Canadian General
Standards Board standard for polyethylene.
• Can also function as a vapour barrier.
Keeping the Heat In 2 Materials
Caution: Exterior products should not be
used indoors – they may be hazardous when
their volatiles are inhaled in a confined space
over an extended period of time. Check the
manufacturer’s literature carefully.
• Available in wide sheets, minimizing
the number of seams required.
• Acts solely as an air barrier; does not
function as a vapour barrier.
• Generally used to wrap the exterior
of a house; often bonded to exterior
glass-fibre sheathing.
• When installed on the exterior, acts
as a wind barrier, preventing wind
from reducing the effective RSI value
of insulation.
• Should be protected from extended
exposure to sunlight.
Rigid Materials
Most solid building components will act
as barriers to air. These components
include drywall, plaster, plywood, glass,
wood and poured concrete (not concrete
blocks). Insulating materials such as rigid
foam boards also act as air barriers. To be
effective, however, the seams between
these various materials must be sealed
with the appropriate caulking, weather-
stripping or gasket. For example, caulking
can be used between the baseboard and
a wall as well as between the baseboard
and the floor, linking the air-sealing
qualities of three different building
components. The combination of rigid
air-barrier materials forms the house’s
air-barrier system as long as the joints
are well sealed.
Caulking is used to seal joints between
building components. Most joints move
because of changes in moisture and
temperature in the building. Some
caulking materials can seal a larger joint
and accommodate more joint movement than others. Make sure that the
caulking you use is compatible with
the surfaces you are applying it to.
Caulkings are not permanent and will
have to be maintained. They also vary in
their durability, compatibility with
other materials, suitability for painting
and curing time. All sealants will require
some extra ventilation of the house after
application to let the material cure.
Typical curing time will be no more
than two or three days for interior
Acoustical Sealant
• Bonds to most surfaces; excellent for
use on metal, concrete and gypsum
• Excellent for sealing the joints in
polyethylene air and vapour barriers,
but should be used only where it is
sandwiched between two materials.
• Mechanical support (e.g., staples)
required when acoustical sealant
is used to seal the joints in
• Maximum joint width of 16 mm
(5⁄8 in.); accepts some joint movement
(10 percent).
• Very durable (20-year life
• Non-hardening and not paintable;
use should be limited to unexposed
Acrylic Latex
• A water-based emulsion sealant.
• Excellent for non-porous surfaces
such as aluminum, glass and ceramic
tile, but may be used to seal joints
with wood surfaces.
• Maximum joint width of 10 mm
(3⁄8 in.); limit use to joints where little
or no movement is expected.
Keeping the Heat In 2 Materials
• Durable (10-year life expectancy).
• Available in a wide range of colours;
• Can attract dust over time, especially
when used next to floors.
Butyl Rubber
• A synthetic rubber sealant.
• Bonds to most surfaces; particularly
suited to metal and masonry.
• Appropriate for a joint width up to
13 mm (1⁄2 in.); accepts some movement of joint (5 to 10 percent).
• Durable (10-year life expectancy).
• Available in a variety of colours;
paintable after one week’s curing.
• Ventilation required during application and curing (up to three days).
Silicone Sealant
• Solvent-free silicone compound;
produces a flexible, watertight seal
upon curing.
• Good adhesion to most surfaces;
primers may be required on wood,
steel or anodized aluminum.
• Excellent for large moving joints:
up to 25 mm (1 in.) joint width and
12 to 50 percent joint movement.
• Highly durable (over 20-year life
• Most types not paintable.
• Available in several colours and clear;
clear silicone is particularly suited for
sealing highly visible joints where the
caulking should not be noticeable.
• Ventilation required during application and curing.
Polysulphide Sealant
• Produces a flexible sealant upon curing.
• Ideally suited for use on stone,
masonry and concrete surfaces when
used with a special primer.
• Maximum joint width of 25 mm
(1 in.); will accept joint movement
of 12 to 25 percent.
• Excellent durability (over 25-year
life expectancy).
• Available in several colours;
• Ventilation required to remove
potentially toxic vapours.
Urethane Foam Sealant
• Available in a dispensing system with
spray nozzles or individual aerosol
spray cans.
• Foam types are available with different rates of expansion depending
on ingredients and the amount of
pre-curing. Check the cans carefully
for details on sizes of cracks that can
be filled. Some types expand slowly
and moderately; others expand
quickly and greatly. Use gloves and
a drop cloth.
• Bonds well to most surfaces except
polyethylene, teflon or silicone plastics.
• Very good for filling larger joints and
cavities where conventional sealant
materials would not be suitable (i.e.,
header/joist intersections and around
plumbing and vent openings).
• Should not be used at window headers since it can transfer structural
loads if the wall settles.
• Good durability (10- to 20-year life
• Like all insulating foams, must be
covered with a fire-resistant material.
• Ventilation required to remove
potentially toxic vapours.
Keeping the Heat In 2 Materials
Electrical outlet gasket
High-Temperature Stove or Muffler
• For use in areas where there are high
temperatures but no joint movement.
• Typically used in conjunction with
other materials for sealing around
masonry or factory-built chimneys.
Several specialty gaskets have been
developed for sealing joints where
caulking may not be appropriate.
Foam backer rod
Sill Plate Gasket
• Polyethylene foam strips.
• Installed between the foundation and
sill plate during construction or
where existing house walls meet a
new addition.
• Available in 152- and 203-mm
(6- and 8-in.) widths on 24-m (79ft.) rolls.
Electrical Outlet and Lighting
Fixture Gaskets
• Electrical outlet gaskets are more
effective when caulked and should be
used in conjunction with child-safety
plugs to reduce air leakage through
electrical sockets.
Foam Backer Rod
• Closed-cell compressible foam “rope.”
• Excellent for filling deep gaps before
• Available in diameters of 6 to 51 mm
(1⁄4 to 2 in.).
• Foam gaskets are designed to fit
behind the cover plates of electrical
receptacles, switches and lighting
mounts, reducing air leakage into
walls and attics.
Keeping the Heat In 2 Materials
Closed-cell foam
Spring vinyl
Spring metal
Magnetic strip
Door sweep
Full threshold
Spring loaded
Neoprene Gasket
• Flexible and very durable.
• Excellent for sealing joints and penetrations where movement is to be
expected, such as plumbing stacks.
Weatherstripping is used to block air
leakage around doors and the operable
parts of windows. Weatherstripping
comes in a variety of shapes; it can be
a flat strip, tube or “V” shape and can
be designed to work under compression
or by sliding along the joint. To be
effective, the product must close the
gap and not allow air to pass.
When choosing weatherstripping, consider the size of the gap to be sealed and
the durability, ease of installation and
appearance of the product. Look for
products that are flexible and that
spring back to their original shape
quickly and easily. Avoid products that
make it difficult to operate the window
or door.
Compression Strips
Use compression strips where there is a
pressure stress, such as at the bottom of
vertical sliding windows, along attic
hatches or on hinged windows and doors.
Types of weatherstripping
Closed-Cell Foam
• An adhesive-backed foam stripping
available in rolls.
• Easy to install.
• Available as a high-performance compressible polyurethane strip with its
own carrier.
Ribbed Closed-Cell Rubber
• An adhesive-backed stripping available in rolls.
• Very durable; easy to install.
• Good for irregular surfaces but less
appropriate for accommodating long
or varied gap widths.
Tubular Stripping
• Tubular material made with either its
own attachment area or on an attachment strip of a different material.
• Rubber type (as opposed to plastic)
should be used because it is more
• Generally used as a window or door
weatherstrip; installed with nails, staples or screws, depending on the type
of attachment strip.
• Highly noticeable when installed.
Keeping the Heat In 2 Materials
Tension Strips
• Effective for doors and hinged
Door Sweeps
• A vinyl pile or rubber sweep.
• Install with screws through an
attachment strip.
• Screwed via attachment strip to
door bottom.
• Can be used in conjunction with
“V” strips.
• Effective where a carpet has a low
pile or is absent altogether.
– small-format “V” strip for narrow
gaps, such as tight-fitting doublehung windows; and
Magnetic-Strip Systems
• Magnetic attraction between a magnetic strip mounted on the door/window frame and a metal strip mounted
on the door/window provides the seal.
Partial Threshold
• A vinyl or rubber strip, attached to
the door threshold.
– large format for wide gaps, such as
loose windows and doors.
• Effective for doors and hinged windows in moderate climatic conditions.
Spring Vinyl
• Can be used in the same applications
as compression strips as well as in sliding joints in double-hung windows
and doors.
• Adhesive-backed; easy to install.
• Two types available:
• Good durability; polypropylene type
should be chosen over other plastics.
• May not provide good seal in cold
temperatures due to condensation
and frost formation (the PVC case
may stiffen and split).
Spring Metal
• Generally used as a door weatherstrip; most effective when under
light compression.
• Good durability; highly noticeable
when installed.
• Installed using small tacks.
Door Bottoms, Sweeps and Thresholds
• Metal can permanently deform.
The bottoms of doors can be sealed
using a number of systems: door
sweeps, door thresholds and door
bottoms. Door bottoms and sweeps are
usually more durable than thresholds,
although they often provide a less
effective seal.
Combination Types
• Uses a spring mechanism that allows it
to adapt to unequal distances from the
weatherstrip to the door or window.
• Provides an excellent seal.
• Can become damaged by traffic and
Full Threshold
• A combination strip, attached to
• Requires at least 16 mm (5⁄8 in.) clearance below the door to be effective.
Door Bottoms
• Combination strips of vinyl pile or
compressible rubber.
• Attachment strip fits over door bottom.
• Requires a clearance of 8 to
13 mm (1⁄3 to 1⁄2 in.) under door.
Keeping the Heat In 2 Materials
Taping an air duct
Electrical box
Sheathing Tape
Other Items
Duct Tape
• Available for sealing the seams of
housewrap wind-barrier material and
polyethylene air-barrier material.
Electrical Box Air Barriers
• Vinyl and foil tapes can be used to
seal around the seams of heating
ductwork to reduce air leakage, especially where ducting passes through
unheated areas of the house.
• Plastic boxes placed around electrical
outlet and switch boxes before installation.
• Equipped with a flange for sealing to
the main air barrier.
• Also act as vapour barriers.
Keeping the Heat In 2 Materials
Requirements for
Vapour Barriers
The vapour barrier is
an important component of the house envelope; it provides some protection from
moisture damage to the structure and
the insulation materials. To be effective,
the vapour barrier must be:
• resistant to the flow of water vapour;
• durable; and
• located on the warm side
of insulation.
The vapour barrier does not need to be
perfectly continuous like an air barrier,
but it should cover as much of the
building envelope as possible. Although
it needs to be located on the warm side
of the insulation, the vapour barrier can
be installed part way into the wall,
provided that no more than one third
of the insulating value of the wall is on
the warm side of the vapour barrier.
This should be reduced to one quarter
or less of the insulating value in very
cold climates or in buildings with high
moisture sources such as swimming
Like an air barrier, the vapour barrier
can be made up of different materials;
even some existing building components
such as plywood, paint or vinyl
wallpaper may form part of the
vapour barrier.
barrier for walls and ceilings. Areas that
most often require special applications
of vapour barriers include interlocking
ceiling tiles and new drywall. Pay special attention to areas of high humidity,
such as kitchens and bathrooms.
Vapour-Barrier Components
Choosing Vapour Barrier
The effectiveness of vapour-barrier
material is measured in terms of its
“perm” rating. The lower the perm
rating, the more effective the
vapour barrier.
Materials that are considered to be
effective vapour barriers include the
Any material used as a vapour barrier will
need to be durable and resistant to moisture flow. Once these characteristics are
met, the following factors should be
• Is it easy to install?
• polyethylene;
• Can the material also act as insulation or an air barrier?
• aluminum foil;
• Is it appropriate to the other work
• some types of paints;
being done on the home?
• some types and thicknesses
of insulation;
• vinyl wallpaper; and
• exterior-grade plywood.
In most older houses, the layers of oilbased primer paint and varnish finishes
can function as an adequate vapour
Keeping the Heat In 2 Materials
Warning: An older home may contain insulation that is wholly or partly asbestos, usually
white or greyish white in colour, and may be in
a powder or semi-fibrous form. Some older
types of vermiculite insulation may also contain asbestos. Please read the warning on
page 29.
If proper precautions are taken, retrofitting should pose no threat to the
health and safety of the occupants or to
those doing the work.
Almost all building
materials are potentially
hazardous, but, if they
are handled and
installed with care, the
work can be done easily and safely.
• Protect your back when lifting heavy
objects; do not lift and reach at the
same time.
• Take special care when handling
heavy or bulky objects, especially
when going up and down stairs
and ladders.
• Smoking is especially hazardous. Do
not take smoke breaks near insulation or fumes.
• Keep your work site well organized
with tools out of the way of traffic,
and give yourself plenty of clear space
to manoeuvre.
Safety reminders for each type of retrofit
job are noted in the chapters that follow.
This section provides general construction-safety tips and guidelines for
working with different types of retrofit
• Make sure that the work space is well
lighted and ventilated.
General Construction Safety
• Do not work in an attic on a hot day.
Heat stress can cause accidents and
serious illness.
• Common tools such as hammers,
utility knives, staple guns, ladders,
rakes and power tools must be
handled with care. More complicated
equipment such as blowers, foamers
and sprayers require special instruction and practice.
• Have a first-aid kit and a fire
extinguisher handy and know how
to use them.
• Ensure proper electrical supply for
power tools.
• Wear appropriate protective clothing
for the job at hand.
Protecting Yourself and
Your Family
Many of today’s materials give off particles, fibres or vapours that can be harmful to the installer and anyone in the
immediate area. Even natural materials
such as sawdust and plaster dust can be
harmful. Often, the hazard is not from
Asbestos inhalation is associated with
asbestosis, lung cancer and mesothelioma. If
you find such material, check with your local
or provincial health authority to determine
whether you should consult a professional
qualified to work with asbestos. Asbestos
professionals can be found in your Yellow
PagesTM under "Asbestos".
the primary material but from binders,
solvents, stabilizers or other additives of
which you may not be aware.
Fortunately, there are a number of
things you can do to ensure that your
retrofit job is done safely and effectively.
Maintaining a clean work area and separating it from the rest of the house will
minimize exposure to materials.
• Keep fibrous materials and materials
that generate vapours well sealed
until they are needed, and close
them in containers at the end of
the work day.
• Vacuum the work area daily to
remove fibres and dust.
• Provide ventilation for the work area
and isolate it from the rest of the
house by closing doors or hanging
curtains of plastic.
• Provide extra ventilation for the rest
of the house while the work is in
progress and during any curing or
drying period.
Keeping the Heat In 2 Materials
when handling glass fibre, mineral wool
and cellulose fibre insulation. A halfmask respirator with a High Efficiency
Particulate Arrester (HEPA) filter cartridge is recommended when dealing
with any insulation that may contain
asbestos fibres. The respirators are available through safety-supply houses. Buy
a supply of filters rated for the material
you are using and change the filters
according to the manufacturer’s instructions.
In the case of material that contains or
is suspected to contain asbestos, such
as vermiculite, do not disturb the
material. Check with your local or
provincial health authority to determine whether you should consult a
professional qualified to work with the
material. See Warning on page 29.
Wear a hard hat to prevent head injuries
and to protect your hair from insulation
Protective clothing
Read this section carefully and follow
the recommended safety procedures for
working with various materials.
Insulation and Other
Particulate Materials
Fibrous insulation materials such as
glass fibre and mineral wool can easily
irritate the skin, eyes and respiratory
system. Long sleeves, tight cuffs and
loose, thick clothing will help minimize
any skin irritations. Special barrier
creams that protect the skin when
working with fibrous materials are
available from safety-supply houses.
Wear goggles whenever there is any
possibility of insulation dust coming in
contact with the eyes. Eyes can easily
become irritated or inflamed by brittle
glass or mineral fibres, and permanent
damage can result.
Wear a mask for non-toxic particles if
there is a possibility of breathing airborne particles of insulation material.
The tiny fibres from glass and mineral
insulations can cause respiratory tract
irritation and lung inflammation.
Avoid breathing insulation dusts.
Wear a well-designed, snug-fitting halfmask respirator with a particulate filter
A vacuum cleaner is the preferred
method of cleaning up fibres or dust. It
is a good idea to attach an extension
hose to the exhaust port of the vacuum
cleaner and to discharge the vacuum
cleaner to the outside to ensure that any
particles travelling through the filter are
not recirculated in the household air. If
you can only sweep up the material, wet
it first to prevent particles from becoming airborne.
Vacuum your clothing to avoid spreading insulation material around the
house. Wash work clothes separately
from other clothing.
Keeping the Heat In 2 Materials
Plastic Insulations
Rigid polystyrene insulation is essentially an inert material, but it can shed
particles when cut. Use a face mask
when cutting board stock.
Polyurethane and polyisocyanurate
insulations give off harmful vapours
when the rigid boards are being manufactured and when the material is being
sprayed in place on the job site. The
vapour causes skin and eye irritation
and breathing difficulties, even at low
levels of exposure. Residual amounts of
vapour may be present with the rigid
board material. Make sure the work area
is well ventilated. These types of rigid
boards will also shed particles when cut;
use a mask as for polystyrene.
When applying the spray-in-place material, contractors take special safety precautions and use respirators. If you plan
to have foam insulation installed inside
your home, provide additional ventilation until the material has cured.
Warning: Older homes, especially those built
before 1950, were often painted with leadbased paint. Caution should be exercised,
especially when working with older homes’
windows, doors, trim work, wood siding or
porches. For further information, obtain a copy
of the Canada Mortgage and Housing
Corporation (CMHC) publication entitled Lead
in Your Home (Publication No. 61941) by caling 1-800-668-2642. This publication can also
be ordered on-line free of charge at CMHC’s
Web site: www.cmhc-schl.gc.ca. Look under
“Products” in CMHC’s catalogue of housing
renovation publications.
A variety of caulking materials have
widely different chemical compositions.
However, all caulking materials share
the following common characteristics:
Fumes from caulking can cause respiratory irritation or other allergic reactions.
Make sure the work area is well ventilated and provide additional ventilation
to the home during the curing period.
The curing time can vary from days
to weeks.
• They all use solvents to keep the
material pliable until it is installed.
Note: Follow directions when caulking
is specified for exterior use only.
• Once applied, the solvents will evaporate and fumes will be given off as
the material sets or cures.
Keeping the Heat In 2 Materials
Retrofitting poses potential health problems for
people with allergies,
asthma or chemical
sensitivities. The
following are options for those
in that situation:
• Choose materials carefully.
• Take extra precautions when working
with the material.
• Plan the work to minimize exposure.
Some materials are less troublesome
than others. By carefully choosing
materials, exposure to irritating substances can be avoided or reduced. For
example, rigid board insulations do not
shed dust or particles unless they are
cut, and some caulkings have a shorter
curing period than others. Also, finishing materials such as paints and stains
with reduced toxicity are now available
for the chemically sensitive.
Being cautious when working with
materials can also reduce exposure for
you and your family. Segregate the work
area, using sheets of plastic if necessary,
and don’t wear work clothing in other
areas of the house. Keep the work area
clean, vacuuming frequently. Store
materials outside of the house until they
are needed, and keep caulking tubes,
insulation bundles and paint cans
closely covered when not in use. Provide
additional ventilation to the work area
and to the whole house while work is in
progress and during curing periods.
If you have special health concerns, you
may also wish to seek advice from your
allergist or family doctor, who may be
able to help you select materials that are
more easily tolerated. For the chemically
sensitive, this may involve a series of
exposure tests to small samples of
material. Your allergist also may be
able to direct you to contractors who
are experienced in undertaking renovation work for clients with allergies or
chemical sensitivities.
Health considerations may be a major
factor in the decision to insulate from
the outside of the house instead of the
inside. If you do work from the inside,
plan the job so that it’s done as quickly
as possible. This may mean hiring a
contractor to do all or part of the work
or staging an old-fashioned work bee.
Where major renovations and retrofit
will affect the whole house, you may
wish to consider sending the family on a
vacation or moving to temporary quarters while the work is under way.
3 Comprehensive Air-Leakage
Keeping the Heat In
Air-leakage control is the single most
important retrofit activity, and it should
be considered first in any retrofit strategy. Blocking air leaks brings many
benefits: increased comfort, reduced
heat loss, protection of the building
structure and reduction of the amount
of noise and dust that enters from
Comprehensive air-leakage control is
the systematic identification and sealing
of as many air-leakage paths as possible.
The ventilation system also should be
considered. Many of the leaks are
obvious breaks in the air-barrier system,
such as through and around windows,
doors and electrical outlets. Other air
leaks are more difficult to identify, such
as bypasses around chimneys and
plumbing stacks that can channel air
directly from the basement to the attic.
Keeping the Heat In 3 Comprehensive Air-Leakage Control
Finding Leakage Areas
Part I
Comprehensive air-leakage control can
result from a systematic effort of weatherstripping, caulking and applying
gaskets and tapes. Air-leakage control is
also an essential part of every insulating
job. Every time you insulate, you must
also install or upgrade the air-barrier
system. This will help you to get the
most from your insulation job and help
ensure that moisture does not enter into
the insulation or building envelope.
Warning: Furnaces, fireplaces, woodstoves and any other fuel-burning
appliances also require air for combustion and for diluting and exhausting the
products of combustion out of the
house. If there is not enough air, it is
possible that the chimney or flue could
backdraft or spill dangerous gases
into the house. Refer to the section
entitled “Combustion Air” on page 121
for further information. Also, if you suspect that you have a problem, you
should speak to your heating contractor.
House as a System
Remember that the house works as a
system in which each component is
related to other components. Changing
one thing can affect other aspects of
the house.
This is especially true with air sealing,
which can affect the house moisture
flows, and combustion and ventilation
air supply. As the envelope is tightened,
household humidity levels rise. This can
cause condensation and moisture problems. Less air is available for combustion
appliances and less fresh air circulates
throughout the house. Therefore, an
important part of comprehensive airleakage control is attention to wholehouse ventilation and combustion-air
Caulking and Other
Air-Sealing Materials
Part II
Each house will respond to comprehensive air sealing in its own unique way.
This has to be monitored in each case.
Older houses may require remedial
measures before comprehensive air sealing; moisture that has crept into the
walls over time can result in mould
buildup, and the house’s wind and air
barriers may need repair or replacement.
The best way to avoid problems is to
understand how they occur and to take
steps to control humidity and ventilation.
Humidity, ventilation and combustion
air are discussed in more detail in
Chapter 8.
Keeping the Heat In 3 Comprehensive Air-Leakage Control
How to Locate Air
The first step is to
identify where the leaks
occur. Air leaks where
there is a hole in the building envelope
and a pressure difference. In winter, the
house tends to operate like a big, fat
chimney. This means that air tends to
enter the house at lower levels and exit
at the upper levels and ceiling.
Identifying the specific leakage areas
can sometimes require a little detective
work. You can hire a contractor who has
the right equipment to do a test for you.
Or you can do your own detective work
by making a “draft detector” and using
the checklist of leakage areas and perhaps your own “pressure test” to locate
those places where air is leaking.
Leak Detector
There is an easy way to locate air leaks:
make yourself a “leak detector.” All you
need are incense sticks. Hold two or
three together for more smoke and
easier detection. Powerful leaks will
cause the smoke to dissipate and the
tips of the incense to glow. Slower leaks
will cause the smoke to trail away or
move toward the leak.
On a cold day, check for drafts in all
suspected areas. It is easier to locate air
leaks on windy days. You’ll be surprised
to discover how many spots need to be
sealed with caulking or weatherstripping. You should also check for possible
leaks on the interior walls and features
of your house. There may be a direct
route through partition walls or along
floor joists to the outside that should
be sealed.
Pressure Test
Professional air-sealing companies often
use a depressurizing fan test to identify
and measure the air leaks in a house. A
powerful fan is inserted in a doorway,
and all intentional openings – windows,
doors, chimneys and vents – are closed
or sealed. The fan depressurizes the
house and leaks are easily identified
Leak detector
where air rushes into the house. A professional fan test can also determine the
total leakage area in the house, the
extent of the work required, the effectiveness of the work as indicated in a
post-retrofit test, and indications of
backdrafting and spillage problems.
You can perform your own rudimentary
fan test by closing all windows and
doors and turning on all the exhaust
appliances in the house, i.e., bathroom
and kitchen fans, clothes dryers (on cool
cycle) and any portable fan placed in a
window (if you can seal around it). Be
careful during the test. Turn off the furnace and water heater (if fuel-fired) to
prevent backdrafting caused by other
exhausting devices.
You can now go around the house with
your leak detector and identify and
mark the air-leakage locations that
should be sealed.
The rest of the chapter looks at caulking
and installing air and vapour barriers.
See Chapter 7 for a discussion on weatherstripping windows and doors.
Keeping the Heat In 3 Comprehensive Air-Leakage Control
Do-it-yourself pressure test
Typical leakage areas
Checklist of Leakage Areas
• cracks in the wall finish or ceiling;
• attic access doors;
A few areas of the house deserve special
attention, but don’t limit your detective
work to just these places.
• the joint where a wood frame wall
joins a masonry wall or chimney;
• around chimneys;
Inside the main living areas, check the
• window-glass panes for tightness, and
around both the window sash and
the window casing;
• around the door, including the
threshold and around the
door frame;
• electrical outlets, including ones on
interior walls;
• exhaust fans and vents (these should
vent to the outside and close properly
when not in use);
• corners where two walls meet with an
imperfect seal;
• light fixtures in the ceiling;
• interior trim and baseboards;
• doors and hatches into
unheated attics;
• fireplace dampers and
fireplace bricks;
• behind bathtubs and under sinks;
• above sliding pocket doors; and
• around plumbing pipes and ductwork.
Inside the attic, check the following
(you may have to move aside existing
• around the plumbing stack and any
other pipes entering the attic;
• around wires or ceiling light fixtures
that penetrate the attic floor;
• around ducting that enters the attic
from inside the house;
• at the junction of the ceiling with
interior wall partitions;
• along any shared walls; and
• the ceiling area over bathrooms
and stairwells.
Inside the basement, check the following:
• where the wood-frame wall (sill
plate) meets the masonry (concrete
or stone) foundation or where joists
penetrate the masonry wall;
• any holes or gaps where the electrical
lines, gas lines or oil fill pipes go
through the wall (be careful!);
• holes for wiring and plumbing going
into external walls;
• leaky ducting or poorly fitted hot-air
registers or cold-air intakes;
• around window and door framing;
• cracks in the foundation wall
and slab; and
• floor drains.
Keeping the Heat In 3 Comprehensive Air-Leakage Control
Air seal any cracks and
penetrations on the
inside surface of exterior
walls, ceilings or floors.
Interior sealing will prevent air from
escaping into hidden cavities in the
walls and roof. The sealing will be protected from the elements on the inside,
and it will be easier to periodically
check its condition. Any moisture that
does reach that wall space, however,
should be allowed to escape
to the outside; otherwise, moisture
problems might result.
It is not advisable to seal the outside
surface of an exterior wall (i.e., the cold
side). Caulk only those cracks that will
allow water entry. If you are painting
the house, try not to plug the joints in
the siding and use a permeable (latex)
paint or stain. The outside of the walls
must be left alone to breathe and
dispel moisture.
Caulking Basics
Use tubes of caulking compound and a
caulking gun for most sealing jobs. Try
the grip with a tube in the gun before
buying. Some guns may have a trigger
spread that may be too large for your
hand. The gun should have a shut-off. A
thumb release on the gun is convenient
since it permits one-hand operation.
If you are doing a complete job, you
will need many tubes of caulking –
one standard size tube will make a
bead 6 mm (1⁄4 in.) wide and 7.6 m
(25 ft.) long.
There are several types of caulking
compounds available. People often have
a bad experience when they first try
caulking because they purchase an
inexpensive or inappropriate caulking
compound. Cheap compounds are
difficult to apply and lack durability. Be
sure to choose a material well suited to
the task. See pages 33 to 35 for a guide
to the different types of caulking and
their application.
How to Caulk – Step by Step
1. Identify the areas to be caulked
(as outlined earlier in this chapter).
Caulking gun and tube
2. Do not try to caulk in an area where
the temperature is below 5˚C (41˚F); the
compound will become stiff and difficult
to work with. Read labels carefully for
storage and application temperatures.
3. Make sure the area to be caulked is
clean and free of dirt, loose paint and
old caulking. Replace deteriorated wood
and re-nail loose boards. If there are particularly large cracks – greater than
6 mm (1⁄4 in.) – use a special filler such
as oakum or a foam backer rod before
caulking. Push this material into the
crack to a depth equal to half of the
crack width.
4. Cut the nozzle of the tube to a size
that will allow the bead of caulk to
overlap both sides of the crack. Make
the cut square and then break the seal
with a wire or long nail pushed down
the nozzle.
5. Push the caulking gun along at right
angles to the crack or joint. The caulk is
then forced into the crack to fill the gap
completely. Make sure the caulk adheres
to both sides of the crack and that there
is sufficient caulk to allow for movement
or shrinkage.
Keeping the Heat In 3 Comprehensive Air-Leakage Control
Note: If you plan to caulk around items
that are a source of heat (chimney, light
fixtures, fan motors, etc.), be sure to use a
heat-resistant caulking compound. Silicone
or polysulphide sealants usually work well.
Special high-temperature silicones are
available for flue pipes.
Laying a bead of caulking
6. The seal should also be neat.
Effective caulking takes practice, so go
slowly at first, following instructions on
the tube. “Tooling,” or finishing the
bead, can usually be done with a wetted
sponge or finger before the caulk sets,
but do not use your mouth to wet
your finger!
7. Latex and silicone caulk can be
cleaned off with water before they set.
For other caulks, you can try a standard
solvent (e.g., toluene, varsol or brushcleaning solvent) or check the manufacturer’s literature. Be sure to release the
pressure lever on the gun to prevent caulk
from dripping as you move from place
to place.
Installing a polyethylene air and vapour barrier:
1) first sheet over a solid member
2) bead of acoustical caulking
3) second sheet pressed into bead
4) staples through bead
5) wallboard or batten for mechanical support
Other Sealing Materials and
A number of other materials are used to
provide an air barrier at different locations
in the house. These include specialty gaskets and tapes, as well as sheet materials
such as polyethylene, spun-bonded
olefin, rigid insulation, drywall, plywood and sheet metal. Installation techniques are critical when using sheet
materials as an air barrier. All edges,
seams and penetrations in the sheets
must be sealed. Further details are
provided in other chapters.
Air and Vapour Barriers
It is often possible to install a new air
and vapour barrier using sealed drywall
as the air barrier and layers of paint or
sheet polyethylene as the vapour barrier.
Alternatively, sealed sheet polyethylene
can be installed on the warm side of the
insulation to provide both an air barrier
and a vapour barrier. Proper installation
is critical (see illustration above).
• Use wide sheets to minimize seams.
• All seams and edges should overlap
over a solid backing, such as a stud.
Keeping the Heat In 3 Comprehensive Air-Leakage Control
Sealing electrical outlets
Sealing behind window trim
• Run a bead of non-hardening
acoustical sealant between the overlapped sheets over the support.
Tips on Sealing Some of the
Leakiest Areas
• Staple through the sheets and the
bead of sealant. All other staples
should be avoided or minimized.
If you notice a draft through an outside
wall electrical outlet, it must be sealed.
(Some inside wall outlets can also provide leakage paths, so do check them.)
Turn off the power to the outlet by
turning off the circuit breaker or removing the fuse. Check to make sure the
power is disconnected by turning on a
lamp. There are special foam pads,
approved by CSA International, that fit
between the cover plate and receptacles.
You will obtain a better seal if you caulk
the gasket before installation. Place
child safety plugs in seldom-used outlets. Some foam pads come with a gasket that fits on the safety plug.
• The finish (e.g., drywall) acts as an
anchor, securing the seam. If the
polyethylene is recessed in the wall, a
batten can be nailed over the seam to
provide mechanical support.
• Seal all penetrations. Where possible,
they should penetrate at a solid backing such as plywood and be caulked.
Electrical Outlets
If you are installing an electrical outlet
during a renovation, get a good seal by
placing it in a special plastic box that is
available from many hardware or electrical supply stores. Caulk the penetration
for the wire, and seal the new air and
vapour barrier to the edge of the box.
Trim Areas (Baseboards, Mouldings
and Window and Door Casings)
Seal areas of air leakage around all trim.
In some cases, this can be done easily by
sealing all the joints with a flexible caulk
that is clear, paintable or of a matching
colour. A more effective solution for
leaky or poorly fitted trim is to carefully
remove the trim and seal behind it.
Insulate wide cracks with a foam backer
rod and seal them with caulking,
polyurethane foam or other suitable
Keeping the Heat In 3 Comprehensive Air-Leakage Control
Duct for outside combustion air for fireplace
(fireplace plug also shown)
If baseboards are removed, you might
also be able to caulk between the wall
finish and the bottom wall plates and
between the plates and the floor.
Glass Panes
The seal between glass and its wood
frame should be tight. Check the glazing carefully and be certain that all the
seals are intact, with no cracks or missing sections. If not, repair them with
putty or glazing compound. Putty usually costs less, but tends to dry out and
crack faster, unless you put linseed oil
on the wood first. A glazing compound,
on the other hand, lasts longer and stays
semi-soft and usable longer. Remove the
old putty and apply the new materials
with a putty knife. Be sure to press it
firmly into the space for a good seal.
High-temperature caulking should be used to air
seal the metal enclosure around the chimney
A crackling fire makes a room cosy, but
what happens when the fireplace is not
in use? If the damper is left open, warm
air from the room shoots up the chimney. When the fireplace is not in use,
close the damper. Take a flashlight and
make sure the damper fits tightly. If it
doesn’t, fix it yourself or have it repaired.
Even with the damper closed, a great
deal of heat still escapes up the chimney.
Commercially available glass doors for
fireplaces are usually not very tight
or effective. Ideally, you should also
install an outside combustion air duct
to the fireplace to improve operation,
efficiency and safety. Ask at your local
building-supply outlet or wood-burning
appliance dealer if a kit is available.
You can also seal off an unused fireplace. Close it up by putting an airtight
plug of some sort in the chimney or
across the fireplace opening. This can be
made from board material that is clothcovered and provides a good seal at the
edges (see diagram above left).
Check for any air leaks where the chimney meets the wall (remove the trim if
necessary). Caulk this joint with a
flexible caulk.
There may be a large gap where a
masonry chimney rises through the
attic. This space can be partially sealed
by stuffing it tightly with pieces of mineral wool batt. Do not use any material
that is, or may become, flammable.
For greater effectiveness, cut pieces of
sheet metal to fit around the chimney.
Seal all the joints with a flexible, heatresistant sealant (see diagram above
Keeping the Heat In 3 Comprehensive Air-Leakage Control
If you have a factory-built metal chimney rising through the attic, do not
insulate closer than 50 mm (2 in.) as
this can create hot spots in the chimney
lining and can present a fire hazard.
Instead, install a collar of metal or other
fire-resistant material around the chimney and caulk to prevent air leakage into
the attic.
Attic Hatch
Seal the attic hatch exactly as you would
seal a door to the outside. Caulk around
the frame and between the casing and
the ceiling plaster board. Apply weatherstripping along the edges of either the
casing or the access panel itself.
Finally, install hooks with eye bolts or
some sort of latch mechanism to hold
the hatch firmly against the weatherstripping. The hatch itself should be
Cutaway view of a well-sealed attic hatch
Windows That Are Never Opened
Mail and Milk Chutes
If you don’t need a window for ventilation or as a possible emergency escape
route, seal it by caulking rather than
weatherstripping. Caulking is likely to
be quicker, cheaper and more effective.
Install a special strippable caulk that can
be removed when you want to operate
the window again.
Seal the chute if it is no longer in use.
If you use it regularly, seal around the
frame and replace the weatherstripping.
If the chute cover is on a spring, make
sure it closes properly. A drop of oil can
sometimes work wonders or, if necessary, replace the spring. Alternatively,
you can buy a new cover. Consider
closing your mail chute permanently
and replacing it with an outside
Keeping the Heat In 3 Comprehensive Air-Leakage Control
Contracting the Work
Homeowners can usually do an effective
air-sealing job if they have the time and
patience and are conscientious about air
sealing in areas that can be difficult and
uncomfortable to work in (e.g., the
attic). However, professional air sealers
can usually do a much better job
because of their experience in locating
and sealing leaks. Contractors may be
experienced in using a depressurizing
fan door (sometimes called a “blower
door”) with smoke pencils and with
specialty caulking and sealants.
Another service that many air-sealing
companies can offer is testing and
assessment of ventilation and combustion air requirements, including
backdrafting testing.
Typically, professional whole-house air
sealing can cost from $500 to $2,000
depending on the size and complexity
of the house and work required. The
contract should specify each area to be
sealed and the materials to be used.
4 Roofs and Attics
Keeping the Heat In
Adding more insulation is only half the
battle. Even if an attic is already insulated, there may still be an opportunity
to improve the energy efficiency and
soundness of the house through air sealing. Air leaks into the attic through the
many cracks and penetrations can
account for substantial heat loss and can
lead to a variety of moisture-related
problems. The importance of air sealing cannot be overstated.
When you think of adding insulation,
the attic is the first place that generally
comes to mind. Relatively easy access
and few obstructions have made the
attic a favourite starting point for many
homeowners, despite the fact that most
other areas – such as basements and
uninsulated walls – lose more heat than
the typical attic.
This chapter examines methods for
insulating and air sealing a variety of
attic types.
• Part I examines some general conditions that apply to most attics.
• Part II deals with easily accessible
• Part III deals with houses with a half
• Part IV describes retrofit work in
inaccessible attics, cathedral ceilings
and flat roofs.
• Part V deals with renovation where
the attic is converted into living
space, a new roof is added or where
the interior is to be refinished.
Keeping the Heat In 4 Roofs and Attics
Part I
Easily Accessible
Part II
Whichever attic or
ceiling type your house
has, there are a number
of things to examine
before beginning work.
A thorough inspection of the following
features will help you develop your
retrofit strategy.
Most houses with accessible attics have
an interior ceiling hatch, although an
exterior roof or wall-mounted entry is
not uncommon. The hatch should be
large enough to allow you to bring in
materials. If this is not the case or if there
is no access, then an entry should be
installed. Exterior-mounted entries represent one less opening that will have to be
air sealed. However, interior hatches are
more practical if you want to inspect the
attic during the winter months.
Check the roof space for obstructions
and ease of movement. Vertical clearances
of less than 1 m (39 in.) won’t let you
move freely. Attics or roofs without a
working space are covered on pages
67 to 69.
Houses with
Half Storeys
Part III
Check the condition of the roof framing,
sheathing, finish and the soffit and fascia for signs of moisture problems such
as leaks, stains, mould, flaking or rot.
Unchecked moisture problems will
reduce the effectiveness of your insulation and can lead to structural damage
such as wood rot or split rafters. Mould,
mildew, fungal growth or rot are sure
signs of advanced condensation problems. The cause will have to be identified and fixed before adding insulation.
Moisture can come from the outside
due to failure of the roof or flashing.
Typical problem areas include poor
flashing at a hip, valley or the chimney.
Pay particular attention to water marks
on the underside of the sheathing or
along rafters.
Moisture can also come from inside the
house, carried into the attic as water
vapour by air leakage. Typical problem
areas occur around bathroom and
kitchen vents that penetrate the ceiling,
around plumbing stacks and chimney
chases, and at wiring penetrations and
pot lights.
Check the attic in late winter for condensation buildup, which will appear as
frost in cold climates. Checking your
Part IV
and Repair
Part V
attic during or just after a rain storm
will help determine whether moisture
problems are generated by interior or
exterior sources.
Check that any electrical runs in the
attic are in good condition. Any wires
with frayed or torn insulation will have
to be replaced before insulating. Make
sure electrical connections are free of
rust and corrosion. Work safely around
electrical wiring, better still, hire a
professional contractor.
Standard recessed lights are difficult
to seal effectively and can become a
fire hazard if covered with insulation.
However, there are airlight recessed
fixtures approved by CSA International that can be installed safely
under an insulated attic.
Examine the existing insulation for:
• condition (dry, wet, compact, etc.);
• type;
• average depth; and
• coverage.
If the insulation has been damaged or is
likely to pose a health risk, it should be
Keeping the Heat In 4 Roofs and Attics
Some attics are easier to work in than others.
removed. If it is wet, don’t cover it until
the source of moisture is removed and
the insulation is dry.
If the insulation is dry, it will probably
be all right to leave it in place.
Generally, there is little problem in
using two different types of insulation.
Check the depth of the insulation to
determine its insulating value. Compare
this with the recommended insulation
values on page 13.
Check to make sure that the insulation
is distributed evenly and that there is
full depth coverage. This is particularly
important around the perimeter of the
attic above the wall plates. Uninsulated
areas will cause a cold spot where the
wall and ceiling meet, which can lead
to moisture problems. If you are blowing in loose fill, install depth indicators
(e.g., a piece of wood nailed perpendicular to a joist) throughout the area to be
insulated to ensure a consistent depth of
Existing Air and Vapour Barriers
Most houses have a vapour barrier on
the warm side of the insulation. In
newer houses, a polyethylene sheet usually serves as the barrier. In older homes,
the vapour barrier might have been provided by wax paper, kraft paper-backed
batts or layers of paint.
However, very few houses have an effective air barrier, although some houses
built in the last decade may be tighter.
If there is an air barrier, your job will be
made much simpler. Locate the barrier
and determine its condition. Remember,
an air barrier must be continuous; holes
or tears will have to be repaired, and
penetrations through the barrier will
have to be sealed.
Increased insulation means a colder
attic, which in turn means that any
vapour that does escape into the attic
can condense before it can be vented. It
is essential to air seal the attic to prevent
moisture from getting in.
Keeping the Heat In 4 Roofs and Attics
Attics have many potential air-leakage paths.
If there is no air barrier, concentrate
your efforts on comprehensive air
sealing. You can create an effective air
barrier by using caulking, gaskets
and weatherstripping to seal the joints
between building components.
Air Sealing
One sure sign of leakage of warm air
from the house is stained insulation or
frost in the winter. The staining is the
result of dirt that has been trapped by
the insulation as air escapes from the
house. Sealing tips for common sources
of air leakage are described below. It
may help to make a map of where the
light fixtures and walls are before you
go up.
Be sure to seal the following:
• Around the plumbing stack and
any other pipes entering the attic.
Since the plumbing stack moves up
and down due to thermal expansion,
the seal must be airtight yet allow
for movement. This can be accomplished by using a rubber gasket, a
plywood collar in conjunction with
an expansion joint, or a sleeve made
of polyethylene.
• Around wires or ceiling light fixtures that penetrate the attic floor.
Seal holes where wires penetrate
partition-wall top plates with a
compatible sealant. Some sealants
damage the plastic or rubber coating
on electrical wiring. Electrical stores
carry a putty-like sealant specifically
for use on electrical wiring.
• Around ducting that enters the attic
from inside the house; for example,
kitchen exhaust fans, bathroom
vents, etc. Seal joints in the ductwork
with duct tape. Seal the gaps where
ducts penetrate the ceiling aluminum. It is especially important that
no exhaust fans discharge into the
attic. They should discharge to the
outside, but not directly below the
eave vents. The ducts should
stay below the insulation or should
be wrapped with insulation.
Keeping the Heat In 4 Roofs and Attics
• At the junction of the ceiling and
interior wall partitions. Pull back
the insulation to locate any cracks
that have formed along interior walls.
Seal the cracks with a caulking compound. This area will not usually
pose a problem if the interior ceiling
has been plastered.
• Along the edge of shared walls.
There is often a gap between the
party wall (i.e., the shared wall
between units in duplexes, triplexes
and row houses) and the edge of the
attic floor. Ensure that this gap is
well plugged.
• At the top of interior and exterior
walls. Check to see if all wall cavities
are blocked from the attic (usually by
a top plate). If the spaces have been
left or cut open, install a piece of
rigid board insulation in the exposed
cavity. Remember to caulk the edges
of the rigid board. If the top plate is
cracked or poorly fitted, use caulking
and polyethylene to create a tight seal.
• Around attic hatches. Attic hatches
are an obvious but frequently overlooked source of air leakage and heat
loss. See page 52 for details.
• Around the chimney. The National
Building Code of Canada requires that
air spaces between chimneys and floor
or ceiling assemblies through which
they pass be sealed with a non-combustible firestop. See page 52
for details.
Attic ventilation serves a number of purposes: it reduces summer heat buildup;
after air sealing, it is your second line of
defence against water vapour that may
have found its way into the attic; and it
ensures a colder, well-vented attic space
that will be less prone to the formation
of ice dams at the eaves.
Make sure that existing attic vents are
working properly and that they are not
blocked by insulation, dirt or other
materials. You may have to locate roof or
soffit vents from outside if they are not
clearly visible from inside the attic.
Although an airtight ceiling will significantly reduce the likelihood of moisture
in the attic, building codes still require
minimum attic ventilation. The ratio
of vent area to ceiling area should be
approximately 1 to 300. Do not automatically increase ventilation. Creating
a tight ceiling is a far more effective way
of eliminating moisture problems.
Electric exhaust fans are not recommended for attic ventilation. An electric
exhaust can draw more air than can be
supplied through the soffit vents. This
will actually pull house air into the attic,
resulting in greater heat loss and moisture accumulation.
The location of vents is as important as
their number and type. The following
sections detail the best approach,
depending on your attic type.
Remember, vents are important but
they will not prevent condensation on
their own. Ventilation alone will not
solve the problems created by air
leakage. Air sealing is your first line
of defence.
Keeping the Heat In 4 Roofs and Attics
After you have inspected
the attic and carried
out any remedial
work, focus on air
and moisture control,
insulation and ventilation.
Air and Moisture Control
There are three options for installing an
air-barrier system in an unfinished attic:
Installation of polyethylene sheets over attic joists. Note the use of rigid foam
boards at the eaves.
• concentrate on air sealing;
• install polyethylene over the joists; or
Concentrating on Air Sealing
• install polyethylene between the
Where and how to air seal is discussed
also in Chapter 3.
Of the three, the first is the most
practical, since the installation of a polyethylene air and vapour barrier in an
existing attic is fraught with obstructions and requires painstaking attention
to detail.
In conjunction with a comprehensive airsealing job, it is a good idea to paint the
room side of the ceiling with two coats of
oil-based paint or a single coat of latex
vapour-barrier paint to further inhibit
vapour movement. Remember, however,
that ordinary latex paint is not a suitable
vapour barrier
If the attic retrofit is being completed in
conjunction with interior renovations,
the easiest approach is to install a new
air barrier on the underside of the ceiling joists. Pages 70 to 72 outline two
approaches to this technique.
Check the attic during or just after a cold
snap in the winter months. Some frost
buildup is to be expected, but if it is particularly heavy, check to make sure that
ventilation is adequate.
Also, look for other opportunities to seal
air leaks into the attic.
Installing Sheet Material
Over the Joists
If the attic is unobstructed with chimneys, plumbing stacks or structural members, and warm, moist air is penetrating
the attic from the house, consider
installing polyethylene directly over the
existing ceiling joists. This method
involves the least number of seams and
requires less caulking and stapling than
other methods. It also allows you to leave
existing insulation in place. Seal all obvious air-leakage paths before laying down
the polyethylene.
Keeping the Heat In 4 Roofs and Attics
Polyethylene strips are laid between the joists as an air and
vapour barrier.
To avoid trapping moisture between the
plastic and the wood – leading to possible wood rot or other moisture-related
problems – install at least twice the
insulating value over top of the airvapour barrier (the one-third–two-thirds
rule). This means, for example, if the
joist height is 89 mm (3 1⁄2 in.) and
contains RSI 2.1 (R-12), at least RSI 4.2
(R-24) must be installed over top of
the barrier.
Baffles can be used to maintain airflow through the
soffit vents.
the polyethylene to the horizontal rigid
board. Carefully caulk any joints or
seams between materials. Expanding
two-part spray foam kits are also useful
for sealing areas around joists and
Installing Sheet Material Between
the Joists
The main difficulty with this technique
involves sealing the barrier to the wall
top plate, especially at the eaves where
there is little room to manoeuvre.
Where obstructions such as a truss roof
make the previous method too difficult,
install a polyethylene air barrier between
the joists. This is a lengthy, painstaking
process, so make sure you have plenty
of patience.
It is essential to seal this area as well.
Rigid board insulation can help to
bridge the gap in this area. Cut rigid
board to fit between the ceiling joists
and to extend from the exterior wall top
plate toward the attic. A second piece of
rigid insulation, installed vertically, joins
If there is no insulation in the attic, your
job is simplified. If there is insulation in
the attic, it will have to be removed
from the area you are working on and
set to one side. Cut strips of the polyethylene about 200 mm (8 in.) wider
than the joist spacing. Lay a bead of
caulking on the side of the joists all
along their length and install the
polyethylene, holding it in place with a
series of staples (see illustration above left).
Remember, any obstructions in the
attic, such as electrical wires or pipes,
will require cuts in the barrier. These
will need to be carefully sealed to
make the barrier continuous.
Installing Insulation
The most common materials for use in
an accessible attic are batt/blanket types
or loose-fill insulation. In some circumstances, it may be a good idea to use a
combination of types. If there are a lot
of obstructions above the joists, such as
with a truss roof, it may be easiest to
put batt insulation into the joist spaces
and then use loose fill to create a complete blanket of insulation above the
joists and around all obstructions.
Keeping the Heat In 4 Roofs and Attics
Fitting insulation around cross-bracing.
On the other hand, if some spaces are
irregular or obstructed, it may be easiest
to use loose fill. You will have to choose
the insulation types most appropriate
to your situation; refer to the summary
of insulation types on pages 26 to 31.
Batt or Blanket Insulation
Batt insulation is simply pressed into
place between the ceiling joists. If you
purchased the correct width, it will fit
snugly. However, if your joist space is
not the standard 16 or 24 inches, extra
labour will be required to cut and fit
batts properly. Loose-fill insulation is an
option worth considering in this situation. The following are some other installation tips:
• Butt the ends of batts together as
snugly as possible.
The top layer of insulation runs perpendicular to the
bottom layer.
space of 38 to 50 mm (1 1⁄2 to 2 in.)
between the top of the insulation and
the underside of the roof sheathing.
To prevent this space from being
blocked, use baffles between each
rafter space (see illustration at right
on page 60).
• Insulate snugly around cross-bracing
as illustrated above left (avoid cutting
the air barrier). Alternatively, you
can cut one batt into a series of
wedges and then fit a wedge under
each brace.
• The first layer of batts should be
thick enough to completely fill to the
top of the joist space. The second
layer can then run in the opposite
direction, across the joists, blocking
any heat flow through and around
the joists (see illustration above
right). Ensure that there are no gaps
between the two layers of insulation.
• Fill any awkward spaces or gaps
with pieces of batt or with loose-fill
• Blanket insulation basically is applied
in the same way as batts. It may be
pre-cut with a knife or cut on the
spot. Start at one end of the attic and
simply unroll the blanket.
Loose-Fill Insulation
• Loose-fill insulation can be poured
by hand or blown in either by the
homeowner with rented equipment
or by a qualified contractor.
• Batts should cover the top plate of
the exterior wall but not block the
venting. To maintain airflow, leave a
Keeping the Heat In 4 Roofs and Attics
Installing loose-fill insulation (note the markers indicating final depth of insulation.)
• Loose-fill insulation can be poured
on top of the air and vapour barrier.
Level it with a board or garden rake,
as illustrated above left. It’s best to
add insulation to a depth greater
than the height of the joists. This
extra thickness makes levelling a bit
difficult but is worth it. Nail vertical
strips of wood to the side of some of
the joists to help you gauge the depth
of the insulation. Maintain an even
depth throughout the attic.
• Pour the insulation to fill all nooks
and crannies.
• At the eaves, take care to keep the
insulation from blocking the ventilation or from disappearing into the
eaves space. A piece of rigid board
insulation, or a wood baffle, should
be installed before the work begins.
Some building-supply stores now sell
Cutaway view of a well-sealed attic hatch
cardboard or foam plastic baffles that
can be stapled between the rafters. In
any case, be sure that the insulation
extends out far enough to cover the
top of the exterior wall.
• If your loose fill is deeper than the
joists, build a crib around the attic
hatch so that it can be filled to
the edge.
• The bags of insulation material will
list how many square metres (or
square feet) each bag should fill in
order to give the required RSI value.
Knowing the size of the attic will
help you determine the number of
bags you will need.
• If you are having a contractor do the
work, calculate the RSI value that
you want and check the bags of insulation to be used. They should indicate the area that one bag will cover
at the selected insulating value. You
and the contractor should then agree
on the total number of bags to be
used, the expected insulating value
and the minimum settled depth of
insulation throughout the attic.
Additional Tips
• You can insulate and/or seal around a
masonry chimney, but before you
start, you must check the state of the
chimney and any surrounding framing. If you see signs of charring,
smoke/soot deposits, crumbling
masonry or mortar, or if you see evidence that the chimney lining is
deteriorating, do not insulate it. Call
a chimney specialist to repair and
insulate it at the same time. If your
chimney is in good condition, you
can fill the space between a masonry
chimney and the wood frame around
it with non-combustible insulation
that is certified to the appropriate
Keeping the Heat In 4 Roofs and Attics
must be increased because the vents are
covered with screening (to keep out
insects, etc.) and with baffles (to keep
out rain and snow).
Different types of ventilation:
1) soffit vents
3) ridge vent
2) gable end vent
4) roof vent
CSA International standard. Then air
seal over the insulation with a nonflammable material such as sheet
metal and high temperature caulking
(see diagram on page 51). Make sure
that this is an application that is
specified by the manufacturer. Leave
50 mm (2 in.) of space around factory-built metal chimneys to prevent
any heat buildup that might create a
fire hazard. This space should be
sealed against air leakage (see page 52
for details).
• Don’t forget to seal the attic hatch
(see page 52).
• If you live in a row house and share a
concrete-block wall with your neighbour, this wall should also be insulated; otherwise the convection
currents that circulate in the hollow
core of the wall will transfer heat to
your attic (see pages 65 and 66 for
details on complications in attics).
• Do not cover recessed light fixtures,
and be careful not to insulate too
closely around flue pipes and gas
vents. Insulation will tend to cause
heat buildup and create a potential
fire hazard.
Houses with peaked roofs and accessible
attic spaces are the easiest to vent. The
amount of attic ventilation is directly
related to the size of the ceiling area in
the building. In most cases, the ratio of
unobstructed, free ventilation area to
ceiling area should be approximately
1 to 300. Because this ratio refers to
unobstructed ventilation areas, the area
Ideally, locate vents to allow for good
cross ventilation from end to end and
from top to bottom. This means placing
vents at the eaves and at the peak. The
drawing at left shows three types of
vents: on the ridge, at the gable end and
near the peak of the roof. Any of these
are adequate when used in conjunction
with under-eave (soffit) vents.
Fifty percent of the ventilation area
should be continuous soffit vents and
the other fifty percent should be gable,
ridge or roof vents. Ridge vents are
preferable where practical, but they
must be equipped with baffles to deflect
wind blowing up the roof and to prevent the penetration of water and snow.
Occasionally, a house will have been
built with no airflow between the soffits
and the attic space. In this case, install
vents at opposite ends of the attic to
take advantage of cross ventilation.
Keeping the Heat In 4 Roofs and Attics
Knee wall
The wall and floor sections of a half storey should
be insulated.
Houses with one-and-ahalf or two-and-a-half
storeys have attics with
several small sections
that sometimes make
access and insulating difficult. If you
cannot get into these spaces to work,
you may have to hire a contractor. If the
space is accessible, the following section
gives some guidelines on how to do the
work yourself.
It is important to air seal under the knee wall.
Air and Vapour Control
Where you have access to the attic
space, follow the directions for the control of air and vapour flows as outlined
on pages 59 and 60. Concentrate
on sealing all air-leakage paths into
the attic.
Ventilate the attic spaces above and
beside the top storey separately by using
gable vents. Make sure that the vents
prevent wind from blowing through
the insulation.
One major source of air leakage that
cannot be overlooked is through the
ceiling joists immediately beneath the
knee walls. Prevent air leakage in this
area by filling the space with a rigid
insulation board, installed flush with the
back of the knee-wall finish. Seal the
edges of the insulation as thoroughly as
possible. Sprayed polyurethane may also
be practical for controlling airflow into
this space.
A second option is to use gable vents in
the area above the attic ceiling and eave
vents in the side areas. This is a good
option if the house already has working
eaves vents (see diagram at left on page
65). A ventilation space in the rafter section will permit airflow between the
insulated areas. Otherwise, you will have
to install air channels in the section
along the rafters to ensure adequate ventilation (see diagrams at right on page 65).
Keeping the Heat In 4 Roofs and Attics
Each section has its own cross ventilation.
These channels must be on the cold
side of the space, which then can be
filled with insulation.
Theoretically, a rigid foam insulation
could be used; however, batts are less
expensive and easier to handle in confined spaces. If there are any electrical
outlets (careful!) or pipes in the knee
wall, make sure that you keep them on
the warm side of the air and vapour barrier and insulation, and seal the air and
vapour barrier around them.
• Treat the attic floor behind the knee
wall and the attic space over the half
storey’s ceiling (see diagrams above)
exactly as described previously for
standard, unfinished attics.
• The end walls are the full-height
walls that are exposed to the exterior.
Treat these with blown insulation,
exactly as described in Chapter 6.
Ventilation occurs between sections via air channels
installed in the rafter section.
• The knee wall can be treated like an
unfinished attic floor (see page 59),
making allowances for the fact that it
is vertical. Install a combination air
and vapour barrier made from polyethylene strips sealed between each
stud. The air barrier also can be
created by sealing all cracks and
penetrations and painting a vapour
barrier on the interior surface. Next,
install the insulation and secure it in
place. This can be done with frictionfit batts or by securing the insulation
with building paper, cardboard,
olefin sheets or string or wire. One
inch of rigid board insulation nailed
to the exterior side of the studs can
also be used to hold the batt insulation in place (see diagram on page
66). This will increase the thermal
resistance of the wall section and
reduce thermal bridging.
Other Complications
Wall of Heated Room
Some houses have a wall in the attic that
adjoins a heated space. Insulate it as you
would a knee wall.
Shared Wall
Semi-detached or row houses that share
a concrete-block wall will lose heat into
the attic because concrete is a good
conductor of heat, and air circulates
inside (and through) this wall. Ideally,
the shared wall should be plugged at
the ceiling level by having a contractor
drill holes and inject small amounts of
polyurethane foam into the blocks. In
many cases, this will not be possible or
economical. If there is a wood-frame
party (shared) wall at the top of the
block wall, air seal the junction at the
top of the block wall.
• The section in the rafters may be
filled with insulation if all penetrations through the ceiling are sealed
and if this is permitted by local
building codes or standards.
Keeping the Heat In 4 Roofs and Attics
Extra rigid insulation can be nailed over the studs of the
knee-wall section.
The next best alternative is to insulate
both sides of the exterior surface of the
shared wall in the attic. Paint the wall
first with an impermeable concrete
paint or cover it with polyethylene.
Next, tightly secure a layer of insulation
to the wall. The wall normally goes
through the roof line and is plugged.
However, if there is space at the top of
the wall between the concrete blocks
and the roof, or if there are any gaps,
they should be plugged and covered
with insulation material.
Dormer Windows
Many one-and-a-half or two-and-a-half
storey houses also have dormer windows. The walls of the dormer may be
insulated with batts, as described for the
knee wall. Remember that the air and
vapour barrier should be on the warm
side of the insulation and be sealed at all
joints and corners.
The remaining walls and the dormer
ceiling are much more difficult to
insulate. The easiest solution is to have
insulation blown in. Remember to seal
any ceiling fixtures or penetrations.
Some houses will have the attic floored
over, even when it’s not used as a living
space. You can insulate it by lifting the
floorboards and treating it as you would
an unfinished attic. Some or all of the
boards may have to be replaced to
maintain the stiffness of the ceiling.
Alternatively, a contractor can fill the
sub-floor space completely by blowing
in loose-fill insulation through access
holes. Air leaks, such as around plumbing stacks, should be sealed first. To
ensure that the space is filled completely
and at the right density, you and the
contractor should agree on the insulating value to be achieved and the total
number of bags of insulation to be used.
Before insulating, either you or the contractor should check for damaged or
frayed wiring, recessed light fixtures or
other sources of heat that may be concealed beneath the floorboards. All heat
sources must be protected from the
insulation or removed entirely.
You will not likely be able to achieve the
minimum recommended levels for attic
insulation by filling this space alone. It
might be worthwhile to add some insulation over the floorboards to keep them
warm and reduce thermal bridging
through the joists.
Keeping the Heat In 4 Roofs and Attics
If the attic is both
cramped and without a
hatch, all is not lost.
You may be able to cut
a hole in the ceiling in an
out-of-the-way place, such as a closet, or
you may be able to gain access through
either existing or new outside vents.
If you discover that the attic is cramped
but large enough to work in, follow the
instructions on pages 59 to 63. If, on
the other hand, there really is no free
space at all above the ceiling joists,
read on.
How to Insulate an Attic That Is
Too Cramped to Work In
Basically you have two choices. It may
be possible to insulate outside the
building on top of the existing roof
(see pages 72 to 73), or it may be
possible to have a contractor blow in
loose-fill insulation. Choose the
contractor with care – make sure that
the firm has experience in this type
of situation.
If you choose to have insulation blown
in, calculate the RSI value that you
expect to achieve and check the bags of
insulation to be used. They should
indicate what area one bag will cover at
the selected RSI value. You and the contractor should then agree on the total
number of bags, the expected RSI value
and the minimum depth of insulation
to be achieved throughout the attic.
There will likely be no way of installing
a new sheet-material air barrier. If one
does not already exist, it should still be
acceptable to install insulation if the
following conditions are met (even if a
barrier is present, these points are
worthwhile to consider):
• There is no evidence of moisture
• Humidity levels in the house are reasonable (see Chapter 1).
• Any air leaks through the ceiling into
the attic are sealed.
You can achieve added protection by
painting the ceiling below the attic with
a coat of latex vapour-barrier paint or
two coats of oil-based paint.
Ensure that the contractor prevents
insulation from entering the eaves and
blocking the ventilation. If there are
any recessed light fixtures or other
sources of heat in the attic, make sure
precautions are taken to avoid creating a
fire hazard.
Finally, if there are any walls in the attic
space it is unlikely that they can be
insulated by blown-in fill. Consult your
contractor for details.
Ventilating cramped attics can be difficult because of the limited space and
the difficulty of creating an adequate
airflow. Where the roof extends over the
exterior walls, it may be possible to use
soffit vents in combination with roof
vents or build-up ridge vents.
Many houses with cramped attic spaces
lack eaves. In such cases, approach ventilation with caution. The best approach
is to carefully seal the ceiling below
the attic from inside the house, and
then insulate without installing additional vents.
Keeping the Heat In 4 Roofs and Attics
Flat roof
If possible, check the roof space for
moisture problems during or just after a
cold snap in January or February. Some
frost is to be expected, but if the
buildup is especially heavy, you will have
to consider ventilating the space and
work even harder at locating and sealing
all air leaks and reducing humidity levels
in the house.
In any event, it is advisable to check
with local building authorities to determine which procedures are permitted in
your area.
Cathedral ceilings and flat roofs are difficult to
insulate and still maintain a ventilation space.
Cathedral Ceilings and Flat Roofs
A house (or any portion of a house) with
a flat roof, cathedral ceiling or some other
“attic-less” construction is likely to be a
difficult case and will require the services
of a qualified contractor.
The main problem with these roofs is
the limited space for insulation and ventilation. If fact, if there is already some
insulation in the joist space, adding
more may not be economical.
However, if you decide it is worth your
while to increase insulation levels, there
are a number of options. Each option
involves some risk of either moisture
problems or thermal bridges that can
reduce the effectiveness of the insulation. A technique involving blown
insulation is discussed below. Pages 70
to 73 discuss both interior and exterior
retrofits, including the addition of a
new roof.
Keeping the Heat In 4 Roofs and Attics
The existing space between the ceiling
and roof can be blown full of loose-fill
insulation by a contractor. Since this
eliminates ventilation, it is generally not
recommended. Take extra care to make
sure that air leaks into the ceiling are
sealed from below. This is difficult
because wiring and plumbing usually
puncture the ceiling in a number of
places. Moreover, the partition walls
may not be completely blocked off at
the top, allowing large amounts of air to
flow through the interior walls into the
ceiling. Where the interior walls are
completely open to the ceiling, there is
no easy solution unless you are prepared
to have your interior walls blown full of
insulation and sealed along all trim, outlets and other penetrations.
If you choose to fill the interior of a
flat roof or cathedral ceiling, the most
appropriate material is probably cellulose fibre blown in to a high density
(56 to 72 kg/m3 or 3 1⁄2 to 4 1⁄2 lb./cu. ft.).
The contractor should calculate and
confirm the density for each roof cavity.
The high density of the insulation –
combined with comprehensive air sealing – should reduce airflow sufficiently
to avoid condensation problems.
Keeping the Heat In 4 Roofs and Attics
Renovations or repairs
provide an opportunity
to ensure a well-insulated attic ceiling and
walls with an effective air
and vapour barrier.
Attics to Be Finished and Heated
A popular renovation activity is to convert an existing unfinished attic into a
new living space. This can be as simple
as insulating and drywalling the existing
space. It can also be as complicated as
adding new floor joists, lifting part
of the roof for more headroom, and
installing a stairway.
Depending on the depth of the rafter
space, it may also be difficult to achieve
the high RSI values recommended for
attic insulation. If you choose to finish
your attic, take the following steps:
• Install collar beams (collar ties)
between every pair of rafters, as
illustrated above. These will provide
structural support for both the roof
and the new ceiling.
• Ensure that the insulation to be
installed in the rafter spaces will fit
snugly against the top of the walls to
form a continuous thermal envelope.
There must be no gaps around the
perimeter of the attic floor; otherwise, heat will escape and ice
damming may occur near the eaves.
In most cases, it should be possible
to insulate each rafter space all the
way down to the eaves over the top of
the exterior wall.
When insulating each rafter space, leave
a clear space between the top of the
insulation and the underside of the roof
sheathing to allow for roof ventilation.
Check for local code requirements.
Warm air under the attic floorboards
will still be able to bypass this insulation. To prevent this, you will have to
block and seal the joist spaces along the
perimeter of the attic floor. If the floorboards can be temporarily lifted, fill the
space between the joists with a piece of
low-permeability rigid board insulation
and seal it to the joists. If the floorboards are not easily lifted, it may be
possible to spray polyurethane between
the joists along the perimeter from the
rafter space beyond the floorboards.
Collar beams (collar ties) provide
additional support.
• Finally, staple a continuous polyethylene air and vapour barrier to
the rafters and end-wall studs, taking
care to seal the edges and seams with
acoustical sealant.
• If your attic room is not too cramped,
consider building onto the rafters and
studs to allow for more insulation (up
to the recommended minimum level
for attic insulation, if possible). After
installing insulation in the existing
spaces, nail 38 mm x 38 mm (2 x 2)
strapping perpendicular to the rafters
and studs. Space the strapping to suit
the width of the insulation you will
use. However, the strapping should
be no more than 600 mm (24 in.)
apart – measured on centre – or you
will have difficulty attaching the interior finish. Fit insulation snugly
between the strapping, covering all
the rafters and studs. Finally, staple a
continuous, sealed polyethylene air
and vapour barrier to the strapping.
Keeping the Heat In 4 Roofs and Attics
Cross-strapping provides space to add more insulation.
• Insulation between the collar beams
is applied from below in much the
same way, with a continuous polyethylene air and vapour barrier
applied last. If the collar beams have
already been insulated and if there is
access to the upper portion, then
more insulation may be added as in a
normal attic.
• Finally, block off and seal any vents
into those parts of your attic that are
now heated.
Dropped Ceiling
Where headroom is sufficient, constructing a dropped ceiling to hold insulation is an excellent way of thermally
upgrading a cathedral ceiling or flat
roof, especially when planned as part
of a renovation. The following are several options.
Extending the rafters provides space for insulation
and ventilation.
• Construct a new ceiling immediately
below the existing ceiling. If the roof
has exposed joists or beams (usually
for decorative purposes), it may be
possible to close the space in, creating a new ceiling. Batts or rigid
insulation can be installed in the
space followed by a continuous air
and vapour barrier and a new ceiling.
In all cases, moisture can cause difficulties. Review the section on moisture control in Chapter 1 before
considering this option.
• If you choose to build a new ceiling
from below, remember that you must
prevent warm air from getting into
the new cavity space and bypassing
the insulation. This will involve sealing the perimeter of the new ceiling
and any possible air leakage paths
through partition walls.
• Existing rafters can be extended to
accommodate additional insulation.
This can be done by cross-strapping
the existing rafters or by extending
the rafter cavity with 38 mm x 89 mm
(2 x 4) lumber and plywood gussets
(see diagrams above).
Although it is not necessary to remove
the interior finish and expose the rafters
when cross-strapping – as it is when
extending the rafters – it is a good idea,
since you can check the state of the
insulation and see if there is a vapour
• You can add rigid insulation directly
to the surface of an existing ceiling.
The advantage of this technique is
that you will avoid the mess and time
required to tear down the ceiling.
However, it will make access to the
space between the ceiling and the
attic floor more difficult (e.g., to
install recessed light fixtures).
Keeping the Heat In 4 Roofs and Attics
Rigid board insulation must be mechanically fastened directly to the roof structure. Adequate nailing surfaces must
also be provided for the new ceiling
finish. If the rigid board insulation is
doubling as the air barrier, make sure
the boards are tightly fitted and that
seams are well sealed. Electrical fixtures
will have to be extended to accommodate the depth of the new ceiling.
Adding a New Roof
Insulation can also be added on top of
an existing roof. This option is suitable
for cathedral ceilings but can be justified
only when major exterior alterations,
such as a new roof, are required. For the
average house, the cost of re-shingling,
installing new sheathing and replacing
eavestroughing, soffits and fascia, as well
as disposal and haulage costs and the
cost of installed insulation, will cost
several thousand dollars. You will almost
certainly need the services of a qualified
Blocking insulation
A new insulated roof can be built up over the old roof.
• A relatively straightforward method
involves installing rigid board insulation over the existing roof (see
diagram above). The higher RSI
value of rigid insulation means a
smaller increase in the roof thickness,
although several layers of insulation
may be needed to meet the desired
RSI level.
Sheet polyethylene is first placed over
the existing roof to provide the air and
vapour barrier (providing the one-third–
two-thirds rule is followed, but see comments in the last paragraph of item 3,
on page 20). Alternatively, low-permeability rigid board can be installed with
the joints taped to prevent air leakage.
This step is not necessary if there is
already an air barrier.
It is important to insulate (“block”) and
air seal the spaces between the joists
along the perimeter of the roof. This is
to prevent heated air from escaping
around the insulation. Line up the edges
of the blocking with the inside finish of
the exterior wall and thoroughly caulk
all seams.
• A new roof can be framed over the
existing roof and filled with batt
insulation. The addition of a new
roof frame may add to the structural
loading of the entire assembly. Check
with a building inspector before
beginning the work.
Keeping the Heat In 4 Roofs and Attics
Although sealing the air barrier on the
ceiling to the one on the wall should
pose no difficulties, maintaining continuity at interior partitions will require
some ingenuity and detailed work.
Where partition walls run perpendicular
to the ceiling joists, maintain continuity
by working from above, using connecting strips of polyethylene or extruded
polystyrene. Where partition walls run
parallel to the ceiling joists, install
blocking and nailing strips to provide
support for the new ceiling materials.
Sealing over partition walls
Again, if required, a new air and vapour
barrier can be provided by laying a sheet
of polyethylene directly overtop the
existing roof sheathing.
The load of the new roof must be transferred to the existing structure evenly
and consistently. This is best done by
installing cross-members (purlins)
spanning the length of the roof. Three
purlins – located at the base, the midpoint and the roof peak – will generally
suffice. The size of purlins will vary
depending on the level of insulation
being installed.
Once the purlins are in place, the new
rafters are installed, followed by the
insulation. Place the insulation so that it
prevents air movement and thermal
Leave clear space between the top of
the insulation and the top of the new
roof rafter to allow for ventilation.
Check your building code for details.
It is also possible to leave the ceiling in
place and apply a new layer of drywall,
making sure that all penetrations are
sealed. This method requires less labour
and creates less of a mess. Create the
vapour barrier by painting the ceiling
with two coats of an oil-based paint or a
single coat of latex vapour-barrier paint.
New insulation is added in the attic
according to the principles set out on
pages 59 to 63.
Refinishing the Interior
If the attic retrofit is part of interior
renovations, consider removing the
ceiling and installing a new sheet-polyethylene or sealed drywall air barrier
on the underside of the ceiling joists.
5 Basement Insulation
Keeping the Heat In
How Important Is Basement
Heat Loss?
Most homeowners don’t think of their
basement as a prime source of heat loss,
yet basements can account for 20 to
35 percent of a home’s total heat loss.
Basements lose so much heat because
of the large, uninsulated surface area
both above and below grade level.
Contrary to popular opinion, earth is a
poor insulator. There is also a lot of air
leakage through basement windows and
penetrations, through cracks, and at the
top of the foundation wall (sill area).
Few basements have any insulation at
all, and for most homeowners this
means there is much potential for
improvement. Insulation can often
be tied in with other repair or renovation work, such as damp-proofing or
finishing the basement.
Keeping the Heat In 5 Basement Insulation
How to Insulate
Outside the Basement
Part I
How to Insulate Inside
the Basement
Part II
Types of Basement Construction
The most common type of basement is
the full foundation basement. It may
or may not be finished or be considered
a living space. Full foundations can be
made of many different materials, as
described below.
Many houses have been built with a
partial depth foundation that creates a
crawl space under the house. Some older
homes and cottages are built up on
posts and piers. The space below the
house is open to the outside, although
this can be blocked off. Other houses
are built on a slab-on-grade where there
is no basement or crawl space at all.
Whatever the type of construction, most
basements/foundations have no insulation at all. Even if your house has been
built since the mid-1980s, it may at best
have partial-depth insulation.
Concrete Foundations
Poured or concrete-block foundations
have been built since the 1920s, usually
with parging, damp-proofing and drain
tiles on the exterior. However, anything
more than 20 years old is likely to be in
need of repair. This type of basement
can be insulated from the outside or
inside as long as there are no serious
water or structural problems.
Crawl Spaces
Part III
Open Foundations
Part IV
Older Foundations
(Rubble, Brick, Stone)
Older foundations made of rubble,
brick or stone are often uneven and can
vary in depth and thickness. These
foundations were rarely damp-proofed
and have a high mortar content, which
can absorb water from the soil. They
usually have a history of moisture
problems and should be insulated from
the outside.
Other Types of Foundations
Many newer homes are built with
preserved wood foundations. These
foundations are made with specially
treated wood studs and sheathing and
are generally fully insulated.
Many homes are built without a conventional basement. Examples of these
include houses with crawl spaces and
slab-on-grade. These types are covered
at the end of this chapter.
Concrete Slab
on the Ground
Part V
Basement Assessment
Before planning the job, assess your
basement. The following are some of the
problems to look for.
Water Leakage
Major water leaks (persistent leaks and
flooding in the spring and when it rains)
must be corrected. This could be as simple as sloping the grade and directing
downspouts away from the foundation.
Often the solution requires excavating,
damp-proofing, adding a drainage
system and insulating from the exterior.
Minor water leaks can sometimes be
corrected by directing water away from
the foundation and patching the foundation on the interior.
Correct problems with sump pumps or
sewer backup before insulating.
Symptoms of dampness include staining
or mould growth, blistering and peeling
paint, efflorescence (a whitish deposit
on the surface), spalling (deterioration
of the surface) as well as a musty smell.
Minor dampness may be corrected from
the interior; more serious problems
should be corrected from the outside.
Keeping the Heat In 5 Basement Insulation
Condensation can also form on the
foundation walls in the summer because
the air is very humid and the basement
is cool.
If the basement has an “active” crack
(i.e., one that gets bigger or smaller),
you should seek professional help to
determine if the situation requires
structural repairs.
Poured concrete
Insulate Inside or Outside?
In most cases, insulating on the outside
is best from a technical point of view.
Despite this, it is often necessary to
insulate from the inside for economical
and practical reasons. Sometimes a
combination of approaches is required.
Examine the advantages of each
approach carefully.
Insulating Inside
This may involve installing a woodframe wall and adding batt insulation
(see illustration on page 77). Another
option is to use rigid board insulation
with prefabricated metal channels or
wood framing to hold the insulation,
followed by a layer of fire-resistant
material (e.g., gypsum board) that is
mechanically fastened to the wall.
Concrete block
Normally, a moisture barrier is applied
to the inside face of basement walls up
to grade level, and an air and vapour
barrier is installed on the warm side of
the insulation.
Advantages of Inside Insulation
• It can be incorporated into a plan to
finish your basement.
• The work can be done at any time
of the year and can be done one
section at a time.
• It is often easier and cheaper to insulate the full wall and achieve high
insulating values.
• Your landscaping and driveway will
not be disturbed.
Keeping the Heat In 5 Basement Insulation
Foundations and Frost Action
Some authorities have expressed concern
about the possibility of frost action and structural damage when foundations are insulated
from the inside. The concern is that frost will
penetrate deeper down the outside of the
foundation wall. Extensive surveys and
research have not found this to be a problem.
Under some circumstances, however, such as
particularly frost-susceptible soils in extreme
climates, there could be a problem caused by
some construction techniques. Check with
your local building authorities or see if your
neighbours have experienced any difficulties
with frost action on their foundation.
Interior insulation involves:
1) a moisture barrier
2) a new frame wall
3) insulation
4) an air and vapour barrier
5) finishing
• Obstructions, such as electrical panels, wiring, plumbing, stairs, partition walls and the oil tank, make the
work more difficult and the insulation and air barrier less effective. If
part of the basement wall is already
finished, this too may prove troublesome (although wall panelling may
be easy to remove and re-install).
Disadvantages of Inside Insulation
Insulating Outside
• Insulating from the inside should not
be attempted in basements with a
moisture problem. If your basement
has a history of damp or dripping
walls, you should insulate on the
outside. If you must insulate on
the inside, corrective measures are
necessary to eliminate the moisture
problem before adding insulation.
This involves excavating around the
foundation, damp-proofing and
installing rigid insulation, as illustrated
on page 78. Flashing must be attached
to keep water from getting behind the
insulation, and a protective covering
must be installed on the exposed
sections of insulation.
Advantages of Outside Insulation
• The outside wall tends to be more
continuous and easier to insulate
once the soil is removed.
• You can effectively correct any moisture problems. Rubble or brick foundations and foundations with water
leakage, dampness or other moisture
problems must be insulated from the
outside. Repairing the foundation,
damp-proofing and installing a
drainage system can be done at the
same time.
• There is no disruption in the house
and no inside space is lost.
• The mass of the foundation is within
the insulated portion of the house
and will tend to even out temperature fluctuations.
Disadvantages of Outside Insulation
• Difficulty might be encountered
when digging a trench around the
house. Excavating by hand can be a
tedious, back-straining job. It is
much easier if you have machinery to
do the work.
Keeping the Heat In 5 Basement Insulation
• Storing the dirt can be a problem.
• Excavation cannot be done in winter
and can be a problem in the spring or
throughout the year if the property
has a high water table.
• Features such as non-removable
steps, paved carports, shrubbery, trees
or fences can make the work difficult.
The following sections provide a stepby-step explanation of how to insulate
outside and inside the basement.
Exterior insulation involves:
1) excavating
2) waterproofing
3) insulation
4) drainage system and backfill
5) protective coating and flashing
Keeping the Heat In 5 Basement Insulation
Assessing the
Tools Required
• Tools for excavating (from a pick and
shovel to a backhoe) and installing
• Tools for applying the flashing
(depends upon your choice of
Whichever basement
type your house has,
there are a number of
things to determine before beginning
• Tools for adding batt insulation
to the joist space from the interior
(if necessary).
• outside features that may inhibit
excavation and insulating (porches,
driveways, services, landscaping,
access, lot lines);
(Refer to pages 40 to 42 for general
advice on safe working procedures.)
• indications of structural problems
(cracks, spalling, powdering mortar);
• signs of moisture problems
• insulation requirements (type and
thickness, height and depth);
• the site where the soil can be stored;
• finishing details (protective coating,
Special Safety Considerations
The job could involve extensive digging.
Take it easy.
If any underground services enter your
home (gas, hydro, telephone, water,
sewage), find out where they are before
digging. This is a free service offered
by utilities.
Some rubble foundations may be
partially supported by the soil. If you
suspect this may be the case, get some
expert advice before you dig.
Exposing the foundation wall
and drainage system
How to Insulate Outside the
Basement – Step by Step
The work may require several weeks
of effort. Plan for extra time if several
steps are needed, such as excavating,
repairing cracks, damp-proofing,
installing a drainage system, etc.
1. Digging the Trench
The excavation should go down to the
footings. Never dig below the bottom
of the footings. The width of the trench
should give you room to work in. It is a
big job. Do not make it bigger by oversizing your hole. You can dig by hand,
or you may want to have it done by a
contractor with the appropriate machinery. The excavated dirt can be stored on
a tarp or sheet of polyethylene at least
60 cm (24 in.) away from the excavation. Protect the trench from rain, running water and the elements, and ensure
that people and animals cannot fall in.
Keeping the Heat In 5 Basement Insulation
Some soils are not stable and may
require bracing to prevent them from
collapsing. Consult an expert if you are
in doubt.
2. Preparing the Surface and Site
The insulation should overlap
at corners.
First clean the surface of the foundation
with a wire brush and scraper. Inspect
the foundation for major holes, cracks or
damage. Repair where necessary.
Smooth uneven surfaces with parging.
Allow repairs to dry.
Check the condition of the drainage
tiles, repairing where necessary. Older
homes are unlikely to have these
installed. It is a good idea to install a
system, but only if it can be done properly, draining to an appropriate discharge. It is best to do this after other
work is completed. Consult someone
experienced with drainage systems
before proceeding.
Apply waterproofing down from grade
level to over the top of the footings.
This can be done with two coats of
waterproofing compound.
Check all penetrations through the
foundation wall. These will have to be
sealed, removed or extended out to
accommodate the thickness of the
Draining-type insulations must be
installed vertically all the way
down to the footings. A drain tile
is essential.
3. Applying the Insulation
Three major types of insulation are used
on the exterior of basement walls: rigid
glass-fibre boards, polystyrene or
polyurethane/polyisocyanurate boards.
See pages 29 and 30 for a description of
these insulations. Rigid glass-fibre and
Type IV polystyrene boards are the
materials most commonly used in exterior below-grade applications. Insulation
with drainage capability, such as glassfibre boards, must be used only if they
are applied to the full depth of the
foundation wall, if there is a drain-tile
system, and if the insulation is applied
with no horizontal seams.
Measure and cut the insulation to the
desired height (generally from the top of
the footings to the flashing). Start at one
corner (overlapping at the corners) and
keep the insulation sheets as tight to the
wall as possible. Some experts suggest
using two layers of insulation with overlapping joints. The insulation is held in
place at the top by the flashing and by
corrosion-resistant fasteners and washers
used to secure the protective finish. The
below-grade portion of the insulation is
held in place by backfill.
It may be convenient (although more
expensive) to purchase a special interlocking system of grooved polystyrene
boards with steel channels. These
should be used in the above-grade
portion only to a depth of 30 cm
(12 in.). There are also special clips and
fasteners for applying the rigid board to
the wall; check building-supply stores.
Keeping the Heat In 5 Basement Insulation
“J” channel
“Z” flashing
Wood flashing
Types of flashing
4. Flashing
Flashing helps keep the insulation in
place, prevents water from getting
behind the insulation and provides a
clean, neat junction. There are two
major considerations: the location of the
flashing, which defines how far up the
wall the insulation extends, and the type
of flashing used.
If the siding can be partially removed or
pried up, then standard “Z” flashing
should be used. This is inserted at least
5 cm (2 in.) behind the siding and
building paper.
If flashing cannot be inserted behind
the siding (such as with brick), then
either a metal “J” channel must be
made up and installed prior to the insulation or a wood flashing installed after
the insulation. Flashing should accommodate the width of the insulation and
protective coat. Wood flashing should
be sloped with an overhang of at least
20 mm (3⁄4 in.) and have a drip edge on
the underside.
Ideally, the insulation is carried up past
the header area by at least 15 cm (6 in.).
This often cannot be done because of
practical or aesthetic reasons. If the insulation is carried up only to the header
area or lower, then the header area
should be air sealed and insulated from
the interior. This is discussed later in
this section.
5. Exterior Protection
A covering is needed to protect the insulation from sunlight and damage by
people and animals. It is applied from
the top of the insulation to a point
about 30 cm (12 in.) below ground
level. Some possibilities include the
• Expanded metal lath with cement
parging. Follow the manufacturer’s
• Polymer-modified pargings. These go
directly on some types of insulation
without requiring metal lath. Check
the manufacturer’s literature.
• Pressure-treated plywood. This can
be installed using stainless-steel
• Fibreglass panels or vinyl or aluminum siding that can match the
house siding.
6. Backfilling
The drain tiles (perforated plastic pipe)
should first be covered with 15 cm
(6 in.) of clean gravel – 4 mm (1⁄8 in.) or
larger – and preferably a strip of filter
fabric. If a draining insulation is used,
the gravel should extend at least 10 cm
(4 in.) up the side insulation.
Keeping the Heat In 5 Basement Insulation
Exterior protection should extend below grade.
Backfill in stages, removing large objects
and compacting or tamping the ground.
If the soil is a poorly draining type such
as expansive clay, it would be better to
bring in free-draining soil.
When the hole is finally filled, make
sure the ground slopes away from the
house; usually a slope of 10 percent –
20 cm (8 in.) for the first 2 m (6 ft.) – is
provided to allow for settling. This will
encourage drainage away from the insulation, as will the addition of eavestroughing and downspouts. It is very
important not to direct excess surface
water toward the foundation.
The filled hole may be covered with any
type of surface – patio stones, grass or a
garden. Some additional settling may
take place; it is better to wait before
undertaking any expensive treatments
such as paving.
7. Finishing Details
In the case of wood flashing or the “J”
channel, seal the joint between the
flashing and the house with a suitable
caulking. In the case of brick siding, the
weep holes (holes that allow water to
escape) must remain clear.
Windows in the foundation can usually
be finished by wrapping the insulation
around the foundation to meet the window frame. Lath and parging can be
applied over the insulation to the window frame. The joint between the frame
and parging should be caulked and will
have to be inspected periodically.
The sill should slope away from
the window.
Doors should be outlined with a “J”
channel or equivalent flashing. The door
sill may have to be extended to protect
the flashing beneath the door.
Seal penetrations through the insulation
and covering to prevent wind and water
entry. Some penetrations (gas regulators,
electrical conduits) may be better left
Keeping the Heat In 5 Basement Insulation
Insulating a cold room on the interior
Overlap interior and exterior insulation
8. Insulating the Header Area
If the exterior insulation does not
extend above the header area by at least
15 cm (6 in.), the header area should be
air sealed and insulated from inside the
basement. Caulk the area where the
wood-frame wall meets the concrete
foundation wall at the sill plate with a
good caulking compound such as butyl
rubber or polysulphide to provide the
air barrier. The header can be insulated
with batt and rigid board insulation as
described on page 87.
Part of the Basement Wall Encloses a
Cold Cellar or an Unheated Garage
Apply the insulation inside the basement, against the cold cellar or garage
walls. The wall should be treated as if it
were an exterior basement wall. The
doorway from the basement should be
weatherstripped and insulated. Finally,
insulate the ceiling of the cold cellar
or garage.
A Concrete Porch Is Butted
Against a Basement Wall, a
Paved Driveway or Some
Other Obstruction
Once again, the insulation should
switch to the inside around these
obstacles. There should be at least
0.6 m (2 ft.) of overlap to provide continuous coverage and reduce the heat
loss through the thermal bridge (see
illustration above right).
The outside insulation around the rest
of the basement should be extended
at least 0.6 m (2 ft.) beyond the inside
wall junction (as illustrated above left)
to minimize heat loss at these points.
Keeping the Heat In 5 Basement Insulation
Assessing the
Whichever basement
type your house has,
there are a number of
things to examine before beginning
work since the type and condition of the
wall will influence how you insulate. Be
sure to consider the following:
• interior features that may make insulating more difficult (uneven walls,
stairs, services, cupboards, partition
walls, etc.);
• indications of structural problems
(cracks, bulges);
• indications of moisture problems
(leaks, dampness, efflorescence, blistering paint);
• insulation requirements (type, level,
location); and
• finishing details.
Before adopting a system for applying
insulation and a protective finish to your
basement walls, you may want to consult a local builder and check with local
building authorities to be sure that your
project will meet the requirements of
building codes. Also, some regions have
particular problems, such as frost heave
due to expansive clay soils, and these
special problems should be considered
before beginning work.
The most common choices are between
three types of insulation – batt/blanket
insulation, rigid plastic board insulation
and polyurethane spray. The third type,
which should be applied only by a professional, is highly recommended for
uneven or rubble wall basements that
have moisture problems. Refer to pages
26, 29 and 30 for detailed information
on these types of materials.
Rigid plastic board insulations generally
have a higher RSI value per millimetre
than batts and therefore require less
basement space and a thinner supporting framework. They are also less prone
to moisture damage than the batts.
However, they are more expensive and
must have a fire-resistant covering.
Interior insulation can use
framing and batts or rigid board
insulation with an attachment
Check with your building-supply dealer.
Remember, when choosing an insulation system it is important to calculate
the cost of the whole system under consideration – including the price of support materials (studs and fasteners), the
air and vapour barrier, a fire-protective
covering and installation costs.
Special Safety Considerations
Refer to pages 40 to 42 for general
advice on safe working procedures.
When working inside basements,
remember to follow these guidelines:
Keeping the Heat In 5 Basement Insulation
wall is even and vertical, as the board
material is fairly rigid. It is usually
restricted to concrete-block or poured
concrete walls. Rigid insulation panels
are secured to the concrete using
mechanically attached nailing strips,
and the assembly is protected with
12.7 mm (1⁄2 in.) gypsum drywall
secured to the nailing strips.
Rigid board insulation involves:
1) air sealing the old walls
2) installing the insulation
3) finishing
• Provide adequate temporary lighting.
• Keep yourself and the insulation
materials away from the flue pipe
of the furnace and any other sources
of heat.
• Watch out for older wiring, such
as the knob-and-tube type, that
may be in poor condition. This is a
common hazard when working in
older basements.
How to Insulate Inside the
Basement Using Rigid Board
This method works best if the basement
gypsum board is mechanically fastened
to the wall or nailing strips.
The best system for you will depend, in
part, on the type of finish you will
install and the loading requirements on
the finished wall. For example, vertical
panelling will have different requirements from horizontally installed drywall. Ask at your building-supply outlet
for the different options available.
After you have checked the wall and
made any necessary repairs, air seal all
leakage paths, such as at the sill plate
and around penetrations. This step is
important as it provides the primary
air-barrier system.
You should install at least RSI 2.1
(R-12). Consider installing it in
overlapping layers to minimize heat
loss through the wooden nailing strips.
Be sure to install the insulation snugly
to eliminate air circulation at the edges.
Mechanical fasteners are essential to
secure the gypsum board to the wall.
This often means that wooden nailing
strips are used, with the insulation
placed between or behind the strips.
Alternatively, the insulation can be held
in place with a special wood or metal
nailing strip that fits within grooves or
notches cut in the insulation panels. In
either case, the drywall is screwed or
nailed in place into the nailing strip.
Corrosion-resistant concrete fasteners
secure the nailing strip into the concrete
wall. The insulation can be glued on the
wall as a temporary measure until the
The joist area must also be insulated
and sealed (unless the joists are embedded in concrete). See the next section
for details.
The entire wall must be protected
with 12.7 mm (1⁄2 in.) gypsum board or
equivalent fire protection. This includes
the joist space if a new ceiling is not
Keeping the Heat In 5 Basement Insulation
Top plate detail where the joists run parallel to the wall
How to Frame and Insulate Inside
the Basement – Step by Step
This system consists of a new woodframe wall with batt or blanket insulation, an air and vapour barrier, and
finishing. It can provide high levels of
insulation at a relatively low cost.
Before you begin, be sure to caulk any
cracks between the foundation and
the sill, as well as any other air-leakage
paths. See Chapters 2 and 3 for a
description of the best materials and
Inspect the walls for possible moisture
problems. Occasional dampness on the
basement walls (especially in late spring
or early summer) is all right as long as
the correct procedures are followed
when installing insulation.
When water leaks are major or frequent,
the source of the problem must be corrected and the wall repaired. It may be
Top plate detail where the joists run perpendicular to
the wall
preferable to excavate, damp-proof, and
insulate from the outside.
through the studs and better moisture
Cover the basement walls with a polyethylene moisture barrier that extends
from grade level only to the bottom of
the wall allowing extra at the bottom –
about 30 cm (1 ft.) – to lie under the
new frame wall. This will protect the
insulation, studding and wall finish
from possible water damage.
Because the wall frame is built out from
the wall, the studs will not touch the
cold exterior walls and there will be
space for an extra layer of horizontal
Framing a New Wall
The next step is to install a wood-frame
wall in the basement. There are two
approaches. You can install the new wall
flush to the old wall using 38 mm x
89 mm (2 x 4) lumber. Alternatively,
you can use 38 mm x 64 mm or
38 mm x 89 mm (2 x 3 or 2 x 4)
lumber built out from the wall by
64 mm (2 1⁄2 in.). The second method
takes up more room, but does provide
more insulation, less thermal bridging
The bottom plate should sit directly
on the extension of the polyethylene
moisture barrier. If you never have moisture leakage on the wall to be insulated,
then you can also set the bottom plate
on a bead of caulking compound or
gasketing material to create a tight seal.
Next, fasten the top plate to the bottom
of the joists. Where the wall runs parallel to the joists you will have to build in
a nailing support for the top plate (the
approach you use will depend upon your
particular house). Now is the time to
line up the new wall properly using a
plumb bob or level and straight edge.
Then install the studs 600 mm (24 in.)
on centre (i.e., from the centre of one
stud to the centre of the next) for
38 mm x 89 mm (2 x 4), or 400 mm
(16 in.) on centre for 38 mm x 64 mm
Keeping the Heat In 5 Basement Insulation
Two layers of insulation can be used:
1) horizontal between the foundation wall and the studs
2) vertical between the studs
(2 x 3) lumber. The choice of spacing
will depend upon how much structural
support your finishing material needs.
Make sure that the studs are perfectly
vertical and accurately spaced so that
the insulation will fit in snugly and the
finish can be installed without problems. Measure each stud separately.
Extra framing is needed around windows and doors in the foundation.
If all alignments are perfectly level and
square, you may be able to build the
wall on the floor, tilt it into place, shim
the bottom plate and then secure it.
Use dry lumber for the framing. If not,
allow the framing to dry for at least two
weeks before adding insulation and covering the wall with the air and vapour
barrier. Some temporary bracing may be
tacked on to keep the wet studs from
twisting as they dry.
Rigid extruded polystyrene insulation caulked between
the joists continues the air and vapour barrier up to the
Insulation is installed in two layers.
The first is a horizontal layer between
the studs and the wall. It is important
that the insulation is tight against the
foundation wall. Next, install a vertical
layer and make sure it fits snugly
between the studs. There should be no
gaps or air spaces where convection currents could help heat to bypass the insulation. Insulation should be wide
enough to match the stud spacing and
be cut to fill the full height of the wall.
Install a polyethylene air and vapour
barrier over the studs and insulation.
Leave enough extra polyethylene at the
top to connect to the air barrier in the
joist space as discussed below. Seal all
edges, seams and penetrations in the
barrier with acoustical sealant. All
joints should overlap over a stud and
be sealed with a continuous bead of
sealant that is run between the layers
of polyethylene at the lapped joints.
Staple the polyethylene to the stud
through the bead of sealant.
Except for foundations where the
joists are embedded in concrete, the
joist space should be insulated and
sealed. This can be done by filling the
space with a section of glass-fibre
insulation and then installing a piece of
low-permeability rigid board insulation,
cut to size, in each joist area above the
top plate of the new frame wall. Seal
the edges of the rigid insulation with
non-hardening sealant to get a tight seal.
The polyethylene air and vapour barrier
from the wall is sealed to the bottom of
the rigid insulation.
The same basic technique can be used
where the joists run parallel to the wall.
The last joist that runs above the sill is
usually inset from the foundation wall.
Depending on the layout of the house,
Keeping the Heat In 5 Basement Insulation
Insulation around a cold cellar
this space can be fitted with long strips
of rigid insulation. The polyethylene
air and vapour barrier installed on the
wall is then lapped up and sealed to the
rigid insulation.
Finally, nail up the finishing surface.
Make sure it is tight against the insulation. The polyethylene barrier and rigid
insulation will represent a fire hazard
until covered. This also applies to the
joist spaces.
If the joists are embedded in concrete, it
is better not to insulate the joist area.
This will help to keep the joist ends
warm and dry. However, you should still
air seal around each joist.
Wall Space Interrupted by Pipes,
Ducts or an Electrical Panel
• Move water supply pipes away from
the wall if at all possible. If they cannot be moved, install the insulation
and the air and vapour barrier
behind the pipes so that they are on
the warm side. Never place insulation
in front of the pipes. Any pipes that
pass through the air and vapour barrier should pass through a plywood
board that is sealed to the main air
Basement Wall Is Irregular
Sealed plumbing penetrations
and vapour barrier and the gaps
around the pipes caulked.
• Do not insulate around any flue
pipes. Different clearances are
required depending on the type of
flue. Check with the manufacturer or
a heating-system specialist. Similarly,
furnaces, wood stoves and fireplaces
require clearances from the wall. Do
not insulate if you cannot maintain
the proper clearance.
• Be careful working around the main
electrical panel. Even when the power
to the rest of the house is off, the
panel will still be “live.” It’s better to
have an electrician move the panel
out to accommodate the new wall.
Basement Wall Interrupted by
a Window
• Seal the point where the window
frame adjoins the wall with caulking
compound, and then insulate.
• An irregular basement is usually
made of stone or rubble and is rarely
damp-proofed on the outside. An
interior retrofit is not recommended,
but where no water or moisture
problems exist, it may be possible to
insulate on the inside. Batt insulation
will conform to the irregularities.
When insulating on the inside of
stone and brick foundations, do not
insulate the joist space. This will
allow moisture in the foundation wall
an escape route. The joist area should
still be air sealed. Spray polyurethane
foam has been used successfully to
reduce moisture (see pages 30 to 31).
This product must be installed by a
certified installer and be covered by
an appropriate fire-resistant material.
Part of the Basement Is a Cold Cellar
or an Unheated Garage
• Apply the insulation to the cold cellar
or garage wall separating the heated
basement from the unheated space, as
if it were an external basement wall.
Keeping the Heat In 5 Basement Insulation
Overhangs should be air sealed before insulating.
Insulating a pony wall is a two-step process that creates
a small ledge.
The doorway from the basement
should be weatherstripped and insulated. Finally, insulate the ceiling as
described for unheated crawl spaces
(see pages 90 and 91).
If you insulate your cold cellar, there
will be an added benefit – it will be
colder! Keep a check on the winter temperature so that adjustments can be
made to prevent freezing.
The Basement Has a Pony Wall
A pony wall consists of short sections
of wood frame wall sitting on top of a
conventional concrete foundation. In
this case, the wood-frame section is
insulated between the studs, and the
concrete section is insulated on the
interior (assuming there are no moisture
problems). The insulation on the concrete is extended up about 20 cm (8 in.)
to overlap with the frame section. A
ledge is created at this point (see illustration above left).
An overhang over the foundation should
be air sealed and insulated. It is usually
possible to remove the finish underneath the overhang and air seal the
space between the joists above the foundation with polyurethane foam or
caulked, low-permeability rigid insulation. Insulate the joist space with batt or
blanket insulation before re-installing
the finish. Heavyweight building paper,
housewrap wind or another barrier can
be installed before the finish.
Keeping the Heat In 5 Basement Insulation
Theoretically, a crawl
space can be insulated
in either of two ways:
• the walls of the crawl
space can be insulated
on either the inside or the outside,
creating a heated area; or
• the house floor above it can be insulated to keep heat from getting into
the crawl space in the first place.
Insulating the walls is recommended for
the following reasons:
• Heating ducts and water pipes in
the crawl space will not have to be
insulated and will not freeze. Any
heat loss from the ducts will not be
a total waste.
• The walls can be insulated on the
outside to reduce the internal moisture problems that can develop in
damp crawl spaces and keep the soil
below the footings warm.
Moisture Barriers
If there is no moisture barrier on the crawl
space floor, add one. The barrier should
be 0.10 mm or 0.15 mm (4 mil or 6 mil) polyethylene overlapped at the seams and held
down with a few old boards or some other
scrap material. If there is likely to be
any traffic in the crawl space, you will need to
protect the polyethylene with a 50-mm (2-in.)
layer of sand.
• It is usually easier to do a thorough
insulating job on the walls, especially
when the crawl space is shallow
or the joist spaces are uneven or
oddly shaped.
• Less material is usually required if the
crawl space is of a typical height –
less than 1.5 m (5 ft.).
How to Insulate and Heat a
Crawl Space
From the Outside
• Insulate the outside wall exactly as
described for the outside basement
wall (see pages 79 to 82).
• If outside obstructions (a porch, a
paved driveway, etc.) make it impossible to completely encircle the crawl
space from outside the house, then
the inside of the wall may be insulated at those points.
Make sure that the inside and the outside portions overlap by at least 60 cm
(2 ft.) and insulate the inside portion.
The instructions that follow show
you how.
Insulating outside the crawl
space is similar to insulating
a full basement.
• If your crawl space does not open
into a full basement, it should have
ventilation at a ratio of 1 to 500 (vent
area to floor area). The best time to
ventilate is in the spring because
summer ventilation can increase condensation. Make sure these vents are
closed and well sealed and insulated
each winter!
• If the foundation footings are above
the frost line, insulate on the outside
of the crawl space walls. By insulating
on the outside, the walls will be kept
warmer, avoiding any possibility of
frost heave. Shallow footings can be
kept warmer by placing a layer of
horizontal insulation sloping away
from the foundation.
Keeping the Heat In 5 Basement Insulation
From the Inside
• If using polystyrene or semi-rigid
glass-fibre insulation, insulate in the
same manner as outlined for the
inside of a basement (see pages
84 to 89).
• Apply a polyethylene moisture
barrier to the crawl-space floor
and install adequate ventilation as
described above.
Keep water away from the foundation
walls (slope the ground away from the
house and install eavestroughing where
Partially Heated
Crawl Space
It is possible to insulate between the
joists and create an unheated crawl
space. However, this can lead to problems of freezing pipes, frozen ground
and possible rot at the joist ends. For
these reasons, floor insulation is recommended only when combined with
foundation-wall insulation to create a
partially heated crawl space.
A few points of general importance
should be summarized:
• The air and vapour barrier must be
applied on the warm (top) side of the
insulation. If the floor above the
crawl space is already covered with an
impermeable material (e.g., linoleum
or plywood), you already have a
vapour barrier where you want it.
The solid materials of the floor can
serve as the air barrier, but be sure to
locate and seal any air leaks. The airtightness at the perimeter joist spaces
is critical. This area can be sealed
with polyurethane foam.
• Batt insulation may be held in place
with heavy-duty permeable building
paper stapled to the joists, or by
chicken wire, sheets of polystyrene
bead board or a commercially available insulation-support system.
• Place the insulation firmly against
the floor above. It should be installed
so that it fills the space between the
sub-floor and the support system
(usually the depth of the joists).
• Tape the seams in any heating ducts
and insulate all ducts and water pipes
in the crawl space. Remember, even
insulated water pipes may freeze if
the temperature of the crawl space is
allowed to fall below freezing.
• Make sure that the crawl space is
adequately ventilated in the spring.
Vents should be installed at a ratio of
1 to 500 (vent area to floor area). Do
not ventilate in winter: the vents
should be plugged and insulated.
Insulation on the walls and in
the floor creates a partially heated
crawl space.
• There must be a moisture barrier on
the crawl-space floor.
• If your basement has both a full
basement and a section of crawl
space where the floor has been insulated, remember to insulate the wall
separating the basement from the
crawl space.
• If the ground level inside the crawl
space is lower than the ground level
outside, there is a slight danger that
frost heave can damage the walls by
pushing them inward. Make every
effort to keep water away from the
foundation walls – slope the ground
away from the house and install eavestroughing where necessary.
• There is an added safety precaution:
if freezing becomes a problem, you
may want to install a thermostat
attached to a small heater in the
crawl space. This unit can turn on
and heat the walls when the crawlspace temperature approaches
Keeping the Heat In 5 Basement Insulation
Some older homes and
cottages have open
foundations. They
should be insulated
between the joists in the
same way as crawl spaces. There should
be a good air seal and the insulation
should be protected from the wind and
animals. It may be possible to build an
insulating skirt around the foundation,
creating a heated crawl space.
If the joist space is already covered, the
insulation may have to be blown in.
Read the section on pages 60 to 62
that deals with insulating an attic floor.
Insulating an open foundation is virtually identical, with the following
• The vapour barrier is placed above
the insulation instead of below.
• It is crucial that the insulation is
blown in at a high density so that
there is no air space between the
insulation and the floor above.
Keeping the Heat In 5 Basement Insulation
Insulation is applied to
the foundation of
houses without basements exactly as you
would insulate the outside of a full basement. Refer to pages
79 to 83 for complete details.
If the foundation is shallow on frostsusceptible soils, a near-horizontal layer
of insulation should be installed in the
soil. The closer the footing is to the surface, the longer the horizontal insulation
should be. Consult your local buildings
department or the insulation manufacturer for detailed information.
Interior Insulation
Near-horizontal insulation buried
in the soil provides frost protection to the slab-on-grade.
Contracting the Work
Exterior Insulation
Contracting for the excavation can save
time. If the whole job is being contracted out, ensure that the quote
includes parging, damp-proofing, drain
tiles and aggregate where required, the
type and quantity of insulation used,
the fastening techniques used, sealing of
penetrations, flashing and finishing
details, a sloping grade and clean-up.
Quotes for interior insulation should
include details on wall preparation, the
installation of a moisture barrier, the
type and spacing of the framing, the
type and quantity of insulation, details
on a sealed air and vapour barrier, insulating and sealing details at the header,
sealing of penetrations and finishing
6 Insulating Walls
Keeping the Heat In
Walls can account for 10 to 30 percent
of heat loss in houses. In addition to
heat loss through the walls, there are
many cracks and penetrations that allow
uncontrolled air leakage into and out of
the house.
Types of Wall Construction
Solid Walls
Solid walls include brick, concrete
block, log and wood plank. Solid walls
do not have a cavity that can be insulated. The only way to insulate these
types of walls is to add insulation to the
exterior or to the interior. Many solid
walls do have a small cavity, generally
less than 25 mm (1 in.), that is used to
collect and drain water out of the wall.
Never insulate these cavities or plug
their drain holes.
Keeping the Heat In 6 Insulating Walls
Blown-In Insulation
Part I
Renovating the Interior
Part II
Renovating the Exterior
Part III
Miscellaneous Spaces
Part IV
Concrete Block
Opportunities for Upgrading
Concrete-block walls usually have hollow cores that allow air circulation. The
cores cannot effectively be insulated,
since the block and mortar will continue
to act as a thermal bridge. However, air
can easily circulate inside the block
cores, increasing convective heat losses.
Seal all possible air-leakage routes into
the blocks.
Empty-cavity frame walls are the easiest
to insulate. Insulation can be blown in
from the top and bottom or from the
interior or exterior.
Frame Walls
Frame walls have a cavity that may be
insulated. Different construction techniques determine the size of the cavity
and ease of access from either the interior or exterior. The wall construction
also affects details that can interfere
with the insulation, including top and
bottom plates, fire stops, blocking,
plumbing, wiring, and heating ducts.
A frame house with a brick veneer usually has a 25- to 50-mm (1- to 2-in.) air
space between the bricks and the frame
wall for drainage. The larger cavity in
the frame wall can be insulated, however, the drainage cavity behind the
brick veneer should never be insulated.
Frame walls with some insulation or
solid walls are more difficult to insulate,
although they should be air sealed as
described on pages 48 to 51. They can
be insulated as part of a major repair job
or renovation. Interior work includes
wall repairs, drywall replacement and
decorating and any renovation changes
to the wall. On the exterior, insulating
can be combined with re-siding.
Additions and
New Construction
Part V
It is important to consider both vapour
barriers and air barriers, especially when
extending an existing wall from either
the interior or exterior. Keep in mind
that in most climate zones, the vapour
barrier must be on the warm third of
the finished wall. See pages 14 to 20 for
more details. You must also consider the
location and condition of old vapour
barriers, which could be as simple as
plaster walls with several coats of paint.
Solve any moisture or structural problems before insulating. Indications of
problems include staining, dripping,
mould growth, cracks on the inside wall
finish and in the exterior siding, and
windows and doors that don’t operate
properly because they are out of square.
Keeping the Heat In 6 Insulating Walls
Note: Blown-in cellulose fibre will more readily fill irregular spaces than other insulation
materials. Cellulose is also the only blown-in
insulation that can significantly restrict airflow
when blown to proper densities. Stipulate in
the contract that the density should be no less
than 56 kg/m3 (3 1⁄2 lb./cu. ft.). This density is
approximately one and a half times the density
of insulation normally used for attic applications.
If you have empty
wood-frame wall cavities, have a professional
insulation contractor
blow in loose-fill insulation. Before you proceed, however,
remember that the stud space is likely
only about 90 mm (3 1⁄2 in.) thick. If
there is already 5 cm (2 in.) of insulation, the benefits of blowing in more
will be small and it will be very difficult
for a contractor to do a good job. You
may have to do a little exploring at different locations to find out what is in
the walls. Try looking behind electrical
outlets (with the power off ).
A small hole must be drilled into each
stud space in the walls; in most cases, two
or more must be drilled per storey – not
more than 1.5 m (5 ft.) apart vertically,
and above and below windows and doors.
There are three possible ways of doing
1. From the inside: Small holes of
15 mm to 50 mm (5⁄8 in. to 2 in.) are
drilled through the inside wall finish
and the insulation is blown directly
into the wall.
The holes must be completely sealed
after the job is done. The patch job can
be messy and unsightly unless immediately covered with new paint or wallpaper, which should be impermeable.
This approach works best when combined with redecoration or renovation.
In fact, if the interior finish is in bad
condition and needs to be replaced or
recovered, it should be possible to drill
the holes, blow in the insulation, plug
the holes, install a well-sealed polyethylene air and vapour barrier over the old
interior wall, and apply new drywall
over that.
Insulation blown in from
the exterior
2. From the outside: Most types of
exterior siding can be drilled or lifted to
permit access to the stud wall behind.
Brick siding can have single bricks temporarily removed. This leaves sufficient
space to repair holes in the sheathing.
Ideally, two stud spaces can be filled
from one brick space. Insulation should
not be allowed to enter the drainage cavity between the brick veneer and the
stud walls.
Remember that each stud space will
require two or more holes with this
method. The top hole should be no
more than 30 cm (12 in.) from the top
plate, preferably 15 cm (6 in.).
Make sure the installer patches the
holes section by section rather than
leaving them all until the end. If not,
you’ll have several holes in your wall
which will permit water entry if a flash
storm hits.
Keeping the Heat In 6 Insulating Walls
Blown-in insulation from the attic or basement leaves
the walls intact.
3. From the basement/attic: This can
be the easiest approach as long as the
cavity is open from top to bottom, such
as with balloon frame construction. A
long tube is inserted into the cavity
from above or below to within 15 cm
(6 in.) of the bottom or top of the stud
space. The hose is then withdrawn,
30 cm (12 in.) at a time. At each stage,
the space is allowed to completely fill
with insulation.
All stud spaces in the wall need to be
filled but there should be allowance for
windows and doors, firebreaks, cross
braces and other obstructions in the
wall cavity. The contractor should first
plumb the space and verify the horizontal spacing of studs.
Potential blockages in the wall include wires, pipes,
blocking, windows and doors.
Just as you should choose your contractor carefully, consult closely with the
contractor when choosing insulation.
The characteristics of the different
loose-fill insulations are outlined on
pages 26 to 29.
When you have chosen the material,
figure out with the contractor how
much should be used. Knowing the size
of the wall to be filled and the density
of the application, you and the contractor should agree on the number of bags
to be used – and write it into the contract. Only a small variation from the
target is acceptable. If the contractor
uses too little, the insulation settles and
leaves gaps in the wall. If too much is
used, some of the insulation may be
escaping from the wall into a floor space
or some other area where it is not
needed – a big waste! Make sure the
right amount is used.
Remember to tighten up the air-barrier
system. Seal all air leaks into the wall
and keep your humidity levels low. A
coat or two of low-permeability paint
(oil-based or latex vapour-barrier paint)
applied to the inside surface of the wall
provides a vapour barrier.
Keeping the Heat In 6 Insulating Walls
Caution: Two thirds or more of the total
insulating value of the wall must be on the
cold side of the air and vapour barrier.
Refer to page 20 for more details.
If your plans involve
extensive renovation,
you have two options:
n Rebuild the existing
wall. If you have a woodframe house and you are removing
the existing wall board or plaster, you
can easily insulate the cavity. You
could save even more energy by
adding insulation to the inside surface. Attach 38 mm x 38 mm or
38 mm x 64 mm (2 x 2 or 2 x 3)
strapping across the studs to allow for
a second layer of insulation in the
wall. Alternatively, you can mechanically fasten (not glue) rigid board
insulation directly on the exposed
studs. High R-value boards are more
expensive but thinner, using up less
interior space.
Build a new wall on the inside of
the existing one. With both wood
frame and masonry walls, you may
build a new wall inside the existing
one and then insulate it. If the old
wall has an existing vapour barrier,
such as a polyethylene sheet, it is
preferable to remove it. If the vapour
Insulating the interior involves:
1) insulating the old wall
2) applying the air and vapour barrier
3) cross-strapping
4) horizontal insulation between the strapping
5) option of extending the insulation past partition walls
barrier is in the form of an oil-based
or latex vapour-barrier paint, you can
reduce its effectiveness by scraping
the surface. The new vapour barrier
should be more effective. Typically, a
polyethylene sheet is installed as a
combined air and vapour barrier. The
new frame wall can be installed any
distance from the old wall, depending on the level of insulation desired.
In both cases, follow the relevant part of
the instructions for insulating a basement
from the inside. This includes sealing air
leaks, framing the new wall, framing
around window and door openings,
insulating (ideally in two layers so there
are no gaps), installing an air and vapour
barrier, and installing new drywall.
Keeping the Heat In 6 Insulating Walls
Foam insulation, used carefully,
can insulate and seal gaps around
window and door frames.
A few additional points should be
• If there is an existing uninsulated
cavity, it may be easier and less
expensive to blow in insulation rather
than expose the cavity first.
• When installing a polyethylene air
and vapour barrier, unroll the sheet
across the entire wall area, including
window and door openings. Cut
these later with an “X” from corner
to corner and seal the flaps to the
frame. Make sure the air and vapour
barrier is well sealed at all joints,
openings and interruptions.
• Before you start the work, identify
the areas within the wall that need
work. These areas will include
plumbing, wiring, and heating and
ventilation ducts. Plan for the insulation to extend behind any pipes, electrical boxes, and so on, so that these
obstructions are on the warm side of
the insulation. This may be difficult
when building new inside walls.
Electrical boxes may be moved into
the new wall; moving pipes can be
more difficult. If there are any pipes
in the existing wall (follow them up
from the basement and down from
the bathroom and kitchen), they
could freeze and burst if left outside
the insulation. Move the pipes or
insulate behind them rather than
in front.
• For non-standard stud spaces, cut the
insulation (if the batt type is used)
about 25 mm (1 in.) wider than the
space to be filled.
• Consider extending the insulation
past junctions at partition walls. To
do this, remove the drywall on the
partition wall back one stud space
and cut back the partition wall
enough to extend the insulation
and air and vapour barrier past the
partition wall.
• If space is at a premium, insulate the
rigid board insulation. This will cost
more for the materials, but will
require less space for the same
insulating value.
• If you are rebuilding the existing
wall, seal all cracks around door or
window frames with polyurethane
foam sealant or stuff the gap with
insulation and caulk. If installing a
new wall, you must frame the windows and doors.
Keeping the Heat In 6 Insulating Walls
Extending the insulation below grade provides
continuous coverage.
Installing new siding on
the house provides an
opportunity to install a
rigid board insulation
or batt/blanket insulation over the old siding and
under the new siding. Here are a few
points to keep in mind:
• It is possible to add significant amounts
of insulation to the outside since space
is usually not a limitation (except in the
case of lot-line restrictions).
• Insulate any uninsulated stud spaces
in the existing wall before adding to
the exterior.
Strapping and insulation should fit snugly together.
• Make allowances for extending
window and door jambs, and for
other penetrations such as vents,
electrical service, gas and oil pipes,
and for eavestroughs and downpipes.
• Consider the location of the vapour
barrier. If the new insulation has at
least twice the insulating value of the
old wall, then a new air and vapour
barrier can be installed over the old
wall before installing the new wall
and insulation. This is most often the
case with solid masonry walls and
can be done with a continuous and
well-sealed polyethylene sheet.
• Make sure there is not an air space
behind the existing siding that would
allow cold-air circulation and shortcircuit the new insulation.
• Do not forget air-leakage control at
penetrations, seams and edges, especially at the top/eaves area. This is to
ensure that house air doesn’t circulate
through the old wall and out at the
eaves. Seal penetrations and leakage
points on the interior wall.
• If your basement is not already
insulated, consider extending the
insulation below ground level over
the foundation wall (see pages 79 to
82 for details).
• The framing generally requires a top
plate along the soffit and a bottom
plate attached to the foundation wall.
In some cases it may be necessary to
extend framing up into the eaves,
which is not a problem if you are
planning to replace the soffits anyway.
Keeping the Heat In 6 Insulating Walls
• Make sure that the framing and
insulation fit snugly together
without gaps.
• The new cladding should use fasteners long enough to penetrate the nail
base by 3 cm (1 1⁄4 in.).
Air barrier
• Insulated siding (often polyurethane
foam sprayed onto the back of aluminum or vinyl siding) is an alternative to separate insulation and siding.
The insulating value is not high–
up to RSI 0.70 (R-4). It should be
installed so that there is no air
circulation between the new siding
and the old wall, which can be very
difficult to accomplish.
The box beam can overlap at corners.
• Ensure that the eaves will prevent
water from getting in between the
insulation and the siding. If necessary, add flashing at the top of the
insulation. Caulk the top joints for
good measure.
Rigid Board Insulation
• Any type of rigid or semi-rigid board
insulation can be used.
• Fasten rigid insulation in place
with the appropriate nails and
washers; check with the manufacturer or supplier.
• Strapping over the insulation rather
than on the side of the insulation has
several advantages. It provides a rain
screen and reduces heat buildup
behind the siding. It also provides a
nailing surface for the siding without
creating a thermal bridge.
Batt/Blanket Insulation
• Build a wooden framework over the
entire outside wall to hold the insulation and support the new siding (see
illustration on page 102).
Keeping the Heat In 6 Insulating Walls
Trusses can be hung from the rafters and nailed to the existing wall.
Cross-strapping, in layers perpendicular to each other, can build out the
new wall. Alternatively, a lightweight
frame wall can be hung from the
rafters or supported on a bottom
plate out from the old wall. This
would allow two layers of insulation,
one horizontally behind the frame,
the other vertically between the
studs. In this way RSI 3.5 (R-20) or
higher can be installed.
• Batt/blanket insulation should fit
snugly into the supporting framework without gaps.
Keeping the Heat In 6 Insulating Walls
Warm air rises, but heat
radiates in all directions, so walls and
floors must be insulated
where they separate a
heated space from an unheated space.
This section deals with three special
cases: an unheated garage, a cold cellar
and overhangs.
Unheated Garage
The walls and the ceiling adjoining the
house must be insulated.
The Walls
Refer to pages 96 to 99 for instructions
on wall insulation if the garage is above
ground; refer to pages 79 to 89 if it is
below ground level.
The Ceiling
If the ceiling is open and the joists are
visible, proceed as outlined for open
foundations (see page 92). It may be
desirable and relatively easy to remove
an existing ceiling finish.
Insulate between an unheated garage and the house.
A contractor can blow the ceiling full of
insulation. Read the section on page 66
on how to insulate a covered attic floor.
Any holes cut in the ceiling should be
carefully re-sealed to prevent gas fumes
from vehicles leaking into the rooms
above. Insulation must be blown in to
the proper density to prevent settling.
Cellulose insulation will provide additional air-leakage control if applied to
the right density.
If there is a ceiling finish that you do
not want to remove, you can nail rigid
board insulation to it as long as the
surface is fairly even. The rigid board
may require a fire-protection layer,
depending on code requirements. Seal
any potential air-leakage paths that
would allow air to bypass the insulation.
This is especially important at the
edges, where it may be necessary to
seal around the perimeter of the ceiling.
Seal this area with urethane foam
or with sections of impermeable rigid
board insulation caulked between
the joists.
Keeping the Heat In 6 Insulating Walls
Cold Cellar
Contracting the Work
The cold cellar walls (separating the
heated basement from the cold cellar),
door and ceiling should be insulated.
Apart from saving heat, your cold cellar
will be colder.
Seal the floor of any overhang and fill it
with insulation.
Generally, blowing insulation into a wall
is best done by a contractor with specialty equipment. Include the following
details in the contract: areas to be insulated, access details (where the holes are
drilled and their size and spacing), type
of insulation used, density of blown-in
insulation, number of bags of insulation, clean-up and finishing (final
finishing of the hole plugs is often the
homeowner’s responsibility).
Treat the walls as outlined on pages 83,
88 and 89, making sure that the air and
vapour barrier is on the warm side.
Treat the ceiling as outlined in the preceding section on unheated garages.
• If the overhang is on the first floor,
this might be accomplished from the
basement by stuffing in some batt
insulation to fill the space. The air
and vapour barrier should face up
to the warm side. See page 89 for
more details.
• If the overhang is between the first
and second floor, the problem is
more difficult. If you can easily lift
the floorboards or remove the outside
surface, fill the space with batt
insulation. Seal any openings into
this space.
Look for a contractor who discusses the
need for air sealing and a vapour barrier
on the warm side of the insulation, and
who suggests methods of sealing some
of the more hard-to-get-at locations,
such as overhangs.
Keeping the Heat In 6 Insulating Walls
High levels of insulation, a continuous
air and vapour barrier, and ventilation
are the features of an energy-efficient
attic. Roof trusses are available that
allow high insulation levels over the top
plate of the outer walls. These include
dropped chord trusses and scissors and
parallel chord trusses for cathedral
Renovation often involves
some new construction,
such as the addition of
a room or wing. New
construction provides an
opportunity to install a continuous air
and vapour barrier and high levels of
insulation in an efficient and costeffective way.
The illustration at right shows a typical
cross section of new construction from
the roof to the footings. Note how both
the insulation and air barrier run continuously without breaks or thermal bridging.
The section in the illustration at right
shows a 38 mm by 140 mm (2 x 6) wall
with insulating sheathing. Other wall
systems include interior cross-strapping,
double-wall systems and the use of
trusses. These systems allow the
continuous air and vapour barrier part
way in the wall. Note the recessed
headers that allow the continuous air
and vapour barrier and extra insulation.
High-performance windows are
used wherever possible, i.e., doubleglazed and with a low-E (lowemissivity) coating, or, better,
triple-glazed with low-E coating. The
majority of windows face south. All
windows are sealed to the air barrier.
The foundation has full-depth
insulation, in this example, on the
exterior. Proper damp-proofing, a
drainage system and sloped grade
help ensure a dry basement.
Mechanical Systems
Heating requirements are less than for a
conventional structure. Combustion air
will be needed for all fuel-burning
appliances – or better yet, use
appliances that require little or no
household air to operate. Refer to
Chapter 8 for more information on
mechanical systems.
7 Upgrading Windows and
Keeping the Heat In
Windows and doors can be big energy
wasters for three reasons:
• Glass itself is a highly heat-conductive material. Similarly, many
wooden doors are highly conductive.
• Doors and operable windows have
many paths where air leakage can
• Air can pass through the joints
around window and door frames
unless they are tightly sealed.
This chapter deals with weatherstripping and other ways of upgrading
windows and doors to save energy.
Keeping the Heat In 7 Upgrading Windows and Doors
Part I
Taking Stock
Check the window for
signs of damage before
starting any work. This
includes checking for
rot, mould and/or staining on or around the window, the
condition of the glass, putty and paint,
and the type of operation and condition
of the closing hardware. Some repair may
be needed.
Check the weatherstripping at all
movable joints. Combine a visual
inspection of the existing weatherstripping with a test using a leak detector as
described on page 46. New weatherstripping is a good investment in
comfort and energy savings.
Check the glazing. Windows should
be at least double-glazed. There are
many ways of adding extra glazing
from the inside or outside, permanently
or seasonally.
Part II
Consider new windows. If some of
your windows are beyond repair or if
you are planning to install new windows, look at some of the higher
efficiency models.
coating or windows that are tripleglazed. Frames should be relatively nonconducting, such as wood, fibreglass or
vinyl. Metal frames, even if they have a
thermal break, may be more susceptible
to condensation.
Condensation Problems
Often the condensation occurs between
panes. This is a result of moist house air
leaking past the first pane and condensing on the cold surface of the outer
pane. Even dry houses can suffer from
this type of condensation problem. This
problem is common on second storeys
where there is more air being pushed
out the window because of the stack
effect. The solution is to weatherstrip
the inner sash to prevent air leakage;
make sure that the weep holes, which
allow water to escape, are open to the
Condensation and frosting are common
complaints about windows. Sometimes
the problem is light fogging on some
windows; other times there may be
persistent and heavy frost covering the
glass. Many homeowners buy new
windows only to find that the problem
becomes worse.
Condensation occurs when water
vapour in the air is cooled to the point
where it condenses on the cold surface
as water droplets or frost. The more
humid the air and the colder the surface, the greater the accumulation of
condensation. One solution is to reduce
the humidity levels in the house, as
discussed on page 119.
Alternatively, you can increase the surface temperature of the window and
frame. This can be done by having at
least two layers of glazing; better yet are
windows with a low-E (low-emissivity)
If condensation occurs inside a sealed
double-glazed unit, the problem can be
corrected only by replacing the unit.
Check to see if the window is still under
Keeping the Heat In 7 Upgrading Windows and Doors
weatherstripping types. The cheaper
types are usually less durable and less
effective, so do not choose just on the
basis of cost.
Parts of a window
Windows should be weatherstripped
around the sash to reduce air leakage. If
the windows do not have to be opened
and do not serve as emergency exits,
they can be locked and caulked.
When sealing windows, make sure that
the inside window is sealed more tightly
than the outside window. Otherwise,
you will encounter condensation problems as the warm, moist air from inside
the house becomes trapped between
the panes.
Many different types of weatherstripping
are available. Pages 36 to 38 list a few of
the more common varieties, but it is
certainly not a complete list. Try to visit
a supplier who stocks a wide variety of
In most cases, newer windows will have
built-in weatherstripping, which can
lose its effectiveness over time. Pry out a
sample of the weatherstripping and take
it to the window manufacturer or supplier for replacement with the same type.
Double-hung and single-hung windows
should be weatherstripped on the sides,
top and bottom of the moving sash, as
shown in the diagram above. If there are
drafts around the fixed portion, these
areas should be caulked.
Preparation and installation is
important. This usually involves the
following steps.
• Adjust and square windows that are
out of alignment.
• Remove old weatherstripping,
caulking and blobs of paint. If the
surface is very uneven, apply a bead
of caulking under the weatherstripping or fill and sand the surface to
make it smooth.
• Clean the surface with a clean cloth
and fast-drying mineral spirits or
MEK (methyl ethyl ketone).
• Apply the weatherstripping. With
doors and windows that are used
often, you may want to reinforce the
adhesive types with staples.
• Check the window for smooth
• Periodically check the weatherstripping
for wear.
Sides. The thin plastic V-type weatherstripping is a good choice. Open the
window and slip the stripping up the
crack between the sash and the frame,
with the mouth of the “V” facing
outside. It need only extend to 25 mm
(1 in.) above the top of the closed window. You can do a better job if you first
remove the stop and the bottom sash.
Top. Weatherstrip the space where
the two sashes meet by removing the
lower sash and applying V-type weatherstripping to the upper window from
the inside.
Keeping the Heat In 7 Upgrading Windows and Doors
Note: Every bedroom must have a least one
window that opens from the inside. This is
required by the National Building Code of Canada
for safety reasons.
Polyethylene or Rigid Plastic Storm
Weatherstripping a swing-type
window on the frame or stop
Windows require weatherstripping
on all four sides.
Bottom. Apply V-type or compressiontype neoprene rubber to the window
sill where the closed window will sit or
to the bottom of the moving window
sash itself.
Swing-type windows are treated like
doors. Apply weatherstripping to the
frame so it meets the edge of the sash,
or place it on the stop where it will
meet the face of the sash. The force of a
closed window against the weatherstripping makes a pressure seal.
Single glazing has an RSI value of about
0.16 (R-0.9), so it loses about 10 to 20
times as much heat as the same area of a
properly insulated wall. Storm windows
or double glazing will reduce the heat
that is needlessly lost through the windows in your house by almost half, and
a higher efficiency window will reduce
it by two thirds or more! Improved windows also will make your house more
comfortable by reducing drafts and
increasing the temperature of the interior side of the window. Adding glazing
also reduces the risk of condensation.
The range of the insulating value is
determined by the number of panes,
the thickness of air space and whether
the glazing has a specialty coating.
Window Products and
Storm Windows
Installing plastic sheeting over the window is an inexpensive and easy way to
improve the heat retention of your home
and reduce condensation. The plastic
will be less durable than glass and will
have to be re-installed each year if the
windows are opened. There is an inexpensive kit on the market that has a
plastic sheet that is heat-shrunk in place
using a hair dryer. This system is best
for windows in seldom-used rooms
and basements.
A do-it-yourself plastic storm window is
available, made of a sheet of rigid plastic
and a specially designed snap-in frame.
Some types use a magnetic strip to hold
the plastic in place. The mounting strip
is permanently attached to the window
frame, and the strip pops open to
accommodate the plastic sheets. The
sheet can then be removed and stored in
the summer. The sheets must be handled
carefully, because they scratch easily.
Storm windows can be installed on the
inside or the outside, and they can be
permanent, seasonal or temporary.
Keeping the Heat In 7 Upgrading Windows and Doors
Interior storms must be well sealed to prevent
condensation between glazings.
Removable Storm Windows
Single-pane storm windows are designed
to be installed each fall and removed
each spring (unless you have air conditioning, in which case they stay in
all year long). They can be made to
order by suppliers listed under “Storm
Windows and Doors” in your local
Yellow Pages™ directory. The major
advantage of these removable storm
windows over permanent ones is a
lower cost.
These windows must be checked seasonally; damaged putty must be replaced
and the frames painted regularly to
preserve the wood. Conventional storms
A permanent storm window can allow for ventilation.
should not fit too tightly to avoid
condensation between the storm and
inner window. The inner window
must be very well sealed with caulking
or weatherstripping.
Permanent Storm Windows
The combination-type storm window
has both screening and glass in the same
unit, serving your needs year-round.
These windows have metal frames and
are made to order by specialized suppliers
(see “Storm Windows and Doors” in
your local Yellow Pages™ directory).
Installation can be done by the supplier
or by you.
These permanent storms are more
convenient than the removable type, but
are also more expensive, and cleaning
between the storm and the window may
be a problem. Some units are available
with an energy-efficient low-E coating.
Regardless of which type you choose,
shop around for well-made windows.
Look at the quality of hardware and
weatherstripping and the strength of
joints. These windows are a long-term
investment and can increase your
property value, so quality construction
is important.
Keeping the Heat In 7 Upgrading Windows and Doors
For window coverings to work properly,
they must fit tightly around the window
frame. Air passing behind the coverings
will increase heat loss and create a considerable condensation problem.
Curtains can help reduce radiant heat loss from windows.
New Windows
Most existing windows can be repaired,
weatherstripped and have new glass
added if necessary. However, there are
circumstances when it is appropriate
to buy new windows. New windows
may be required in the following
• the old windows have deteriorated;
• there is extensive damage (such as
rot) to the surrounding wall caused
by the old window;
• you are undertaking major renovations or building an addition; or
• you want changes in window size,
their operation or the appearance of
the house.
For further information on choosing
new windows and doors, refer to
page 133 to order a copy of the
Consumer’s Guide to Buying EnergyEfficient Windows and Doors.
Window Protection and
Windows can be used to provide fresh
air and remove excess humidity and
odours. But be careful – it is hard to
control windows as ventilators and it is
easy to let too much cold air in.
Generally, the high cost of materials for
insulating windows will make this a
low-priority item for most existing
homes. If your windows need new
shades or curtains anyway, consider
methods for reducing heat loss at the
same time.
One of the most practical solutions is to
design or buy a flexible insulating
curtain to pull across the window or roll
down from above. The curtain should
ideally be made from a heavy, multi-layered material covered with your choice
of fabric. Even one or two thick drapes
over a window should do a good job if
tightly fitted. The curtain should fit
snugly along the window ledge or be
weighted for a tight fit along the floor.
A valance or enclosure along the top is a
good way to prevent air from falling
behind the curtain.
Shutters, shades and awnings can be
used to keep the sun out. Window
insulation can be used in the winter to
provide extra insulation for improved
comfort and energy savings.
Keeping the Heat In 7 Upgrading Windows and Doors
Doors, like windows,
should fit snugly so that
air cannot sneak in
around the edges. Poor
installation, years of hard
use, shifting foundations and seasonal
warping can often force doors out of line
with their frames. If they don’t fit snugly,
fix or replace the weatherstripping.
The same techniques for preparing windows applies to doors. This includes any
needed repairs or adjustments, surface
preparation and cleaning, and fastening
the weatherstripping.
Around the frame. Weatherstrip the
tops and sides of any door frame as
illustrated at right.
The easiest and most effective weatherstripping for this use is a good quality
V-shaped vinyl type. It makes contact
with the edge of the door and provides a
good seal even when the door warps
from season to season.
For increased protection, attach weatherstripping to the stop so that it presses
against the face of the door as shown at
right. There are also many types of
combination metal and foam or rubber
weatherstripping that are screwed to the
stop. They should be adjusted regularly
to conform to the changing warp of the
Bottom of the door. Apply weatherstripping to either the door sill or to the
door itself. This can be a difficult area to
seal well, but is worthwhile because this
is often a source of major drafts.
Use durable material that can withstand
traffic and be flexible enough to conform to changes in the door caused by
humidity and temperature. The weatherstripping should also be easy to
replace. A good seal can usually be
obtained with gasketed door-bottom
1) Weatherstripping the face of
the door
2) Weatherstripping the edge of
the door
weatherstripping that attaches to the
door, or with full or partial threshold
weatherstripping that is attached to the
door sill.
When the weatherstripping is applied to
the door itself, a very durable material is
necessary. The most readily applied and
effective choice is the combination type,
which is simply tacked or screwed along
the bottom inside surface of the door.
There should be slots that allow for
some adjustment of the weatherstripping.
Keeping the Heat In 7 Upgrading Windows and Doors
Sealing a door bottom
Replacing the Door
Sometimes it is appropriate to buy new
doors. Take this opportunity to buy an
energy-efficient one. A Consumer’s
Guide to Buying Energy-Efficient
Windows and Doors can help you choose
the right door for your home. Write to
the address provided on page 133 to
order your copy.
Contracting the Work
Air sealing and repairing windows can
be good do-it-yourself projects. Alternatively, these can become part of the
work of an air-sealing contractor (see
Chapter 3). If you are hiring a contractor, consider asking for a quote on some
related air-sealing work.
If you are having some of the windows
in your house replaced, ask the contractor to check the weatherstripping on the
remaining windows and replace it if it is
8 Operating Your House
Keeping the Heat In
By now you should be very familiar
with the “house as a system” concept.
Like any system, however, your house
will run only as efficiently as it is operated. As the homeowner, this puts you
in the driver’s seat. How you live in your
home and maintain and operate it will
have a lot to do with the success of your
retrofit activities. If you operate it
poorly, you will negate a large part of
your retrofit gains. If you operate it
efficiently, you can actually improve
your home’s heating performance.
Even more important, you will create
a healthier, more comfortable living
environment. Most furnaces and boilers
operate below peak efficiency because
of poor maintenance. A well-tuned and
efficiently operating heating system
can significantly reduce your annual
fuel bill.
Keeping the Heat In 8 Operating Your House
Operating and Maintaining
the Heating System
Part I
Follow recommended
maintenance procedures for cleaning and
servicing. For an oil furnace and boiler, this means a thorough
cleaning and tuning each spring. For gas
furnaces and boilers, servicing should be
carried out at least once every two years.
Most of the tune-up should be carried
out by a qualified service technician or
heating contractor. A series of booklets
on heating systems (available from the
address indicated on page 133) will give
you all the facts you need about your
heating system.
Homeowner Maintenance
If you have a forced-air system, keep
return-air grills and warm-air vents
clean and free of obstructions, and
change or clean your filters once a
If you have an electric baseboard
system, keep your heating units clean.
Vacuuming them twice a year should
prevent dust buildup.
The Heating System
and Ventilation
Part II
Hydronic systems perform best when
radiators are relatively free of air. This
means you must remember to bleed
your radiators regularly unless the system has an automatic bleeding capability. Further savings can be achieved by
adjusting the operating temperature of
the water according to outside conditions. A control can adjust the water
temperature to match the changing
demand for heat so you will never be
too hot or too cold, or pay for heat you
do not need.
The greater the difference in temperature between inside and outside, the
greater the heat loss. By turning your
thermostat down a bit, and a bit more at
night, you will lose less. The best way to
ensure that the thermostat gets turned
down is to install a clock or setback
thermostat. The setback thermostat will
perform predetermined temperature setbacks automatically.
A good quality programmable thermostat will provide a clock timer and allow
you at least two setback and reset periods
a day. For example, a temperature
reduction could be programmed in to
start before you go to bed and end
before you get up in the morning. The
Other Features
Part III
A programmable thermostat
second setback can reduce house
temperature when everyone is out of
the house during the day and end just
before you arrive in the evening.
Sizing and Balancing
Heating Systems
A newly retrofitted house will have a
smaller heating need than it had before
the retrofit. This smaller heating
requirement means that the furnace is
now oversized, a condition that can
cause larger temperature fluctuations
and the potential for inefficient on-off
cycling of conventional furnaces.
When a furnace operates less often, the
chimney can get colder between burns.
This can lead to downdrafting and
possible condensation and damage to
the chimney. If your retrofit measures
are extensive and you have a concern
about this, have the system checked by
a qualified heating-system technician.
Keeping the Heat In 8 Operating Your House
In addition, the balance of the heat
distribution will likely have changed.
Insulation and air sealing could mean
that some hard-to-heat rooms are now
easier to heat, while other rooms may
overheat. This may require a re-balance
of the system by either adjusting the
dampers in a ducted system or adjusting
valves in a hot water system.
Ask the service mechanic or heating
contractor who maintains your system
what changes may be required so that
your system operates at top efficiency.
Heating Ducts
Heating ducts running through
unheated or cool basements should be
insulated. First, tape the joints to prevent leakage. While you’re at it, it would
be well worth your while to use aluminum foil duct tape to tape the joints
of all heating ducts, regardless of
whether they are to be insulated or not.
Then take 75 mm (3 in.) or more of
mineral-fibre batts or blankets and cut
them to size. Specially designed batts
are available for this purpose. Wrap
the insulation around the ducts or else
install it lengthwise. Make sure the
entire system is covered, with the insulation taped securely. Don’t wrap the
ducts of a wood-fired furnace within
1.8 m (6 ft.) unless you use a special
non-combustible insulation designed for
wrapping ducts.
It is also a good idea to check return-air
ducts, especially where they pass
through crawl spaces or garages, and
caulk or tape only leaky joints.
For houses with hydronic systems,
placing foil-covered insulation board
between radiators and exterior walls
will reflect heat back into the room that
would otherwise be lost to the outside.
The heat supplied by a fire will not
make up for the loss of heat when
house air is drawn up the chimney.
Consequently, most fireplaces are
unable to provide any net heat gain.
There are several fireplace accessories
such as tightly-fitted glass doors and
outdoor air intakes that offer nominal
improvements on fireplace efficiency.
For information on how to improve fireplace performance, read A Guide to
Residential Wood Heating, which can be
obtained from the address listed on
page 133.
Domestic Hot Water
Domestic hot water systems also consume large amounts of energy – more
than all your lights and appliances combined. In fact, next to space heating, the
water heater is the largest energy user in
the home.
Insulating your water heater storage
tank is a fairly simple and inexpensive
improvement that can help maintain the
water temperature at the thermostat setting. Some new models of water heaters
are well insulated and do not need an
added layer, but a heater that is warm to
the touch on the side of the casing can
benefit from an insulating jacket. An
insulation kit that contains a vinyl-covered insulation jacket, pre-cut tape and
instructions can be purchased from
hardware stores. Follow the manufacturer’s instructions when installing kits.
Insulating jackets are not recommended
for oil-fired water heaters. Caution must
be used when installing an insulating
jacket on a gas-fired water heater in
order to avoid blocking the airflow to
the burner.
Keeping the Heat In 8 Operating Your House
Taping and insulating heating ducts in an unheated space
For more information on insulating
hot water tanks, consult with your local
fuel supplier.
Insulating the hot water tank should
save enough money to pay back the
costs of materials quickly. You can save
even more on your hot water bill by
acting on the following suggestions:
• Insulate hot water pipes that pass
through unheated areas or service
washing machines. The insulation
should be at least 13 mm (1⁄2 in.)
Insulating the hot water tank
thick to be effective. You can use
pieces of batt with duct tape, or the
wrap-type insulation, but the ideal
pipe insulation for existing homes is
the snap-on type. These are long
tubes slit lengthwise that snap over
the piping and then are glued shut.
• Fix leaky faucets. At one drop per
second, you are wasting 720 litres
(160 gallons) per month – or 16 hot
• Run washing machines with full
loads and rinse with cold water.
• Install a flow restrictor in the showerhead pipe and aerators in the faucets.
These inexpensive gadgets will allow
you to do the same job with much
less water.
Keeping the Heat In 8 Operating Your House
Both you and your
furnace need some
fresh air coming into
the house, but most
Canadian homes have too much. In
fact, 25 percent or more of your home’s
heat loss can be due to excess infiltration
around windows, doors and other
cracks. These drafts not only cost you
money, but can make your home
unpleasant during the winter.
How tight is too tight? When do humidity and condensation become problems?
What are the requirements for ventilation and combustion air? This section
looks at some of the implications of
air-leakage control: how it can affect air
quality and the air needed for combustion appliances.
It is worthwhile to take a systematic
look at the moisture balance and
ventilation needs of your house. This
will involve a list of moisture sources,
symptoms of problems and ventilation
requirements. Consider how any renovation or retrofit plans will affect the
house. For example, if the house already
shows signs of excessive condensation,
any plans that include making the
house more airtight will have to include
increased ventilation.
For many, if not most, older homes a
program of comprehensive air-leakage
control will not reduce the air supply
enough to cause problems. Most older
houses experience too much air leakage,
even after air sealing.
• houses where there is competition for
air (fireplaces, powerful exhaust vents);
• houses where there are sources of air
contamination (smokers, hobbies,
etc.); and
• houses that produce a lot of moisture
and have high humidity levels.
Symptoms of Problems
There are times when problems can
occur, even without thorough air-leakage
control. It is important to be aware of
the potential problems, the symptoms to
look for and some of the possible solutions. The following circumstances can
make a house more susceptible to
• houses with electrical heat or a highefficiency furnace (no conventional
Sources of moisture in the home
If you are aware of the symptoms indicating the start of a problem, you can
make adjustments and correct the situation before damage results. Some of the
signs to look for include the following:
• excessive condensation on doublepaned windows;
• staining and mould growth, which
often appears first in bathrooms,
closets and on walls or ceilings
at corners;
• stuffy atmosphere and lingering
Keeping the Heat In 8 Operating Your House
Kitchen and bathroom fans should be used regularly.
• back-puffing/odours from the
furnace; and
• backdrafts from the fireplace.
Low and high windows provide good ventilation.
• Install a sump pump to remove
excessive moisture from the soil
under the slab.
• Fix all water leaks into the basement.
If the problem is one of high humidity
or condensation, the first step is to
reduce the humidity level by controlling
the amount of water vapour that goes in
the air. The following suggestions will all
reduce a home’s humidity levels:
• Do not store wood in the house.
• Avoid hang-drying laundry in the
• Disconnect any humidifiers.
• Cover exposed earth floors in
basements or crawl spaces with a
moisture barrier.
• Do not allow any standing water in
the house or against the foundation
• Make sure the ground slopes away
from the foundation wall and that
there are properly functioning
eavestroughs around the house.
• Ventilate kitchens and bathrooms
during use.
• Adjust your living habits to produce
less humidity (cleaning, washing,
cooking, etc.).
The following table shows the maximum levels of humidity at which there
will be no condensation on doubleglazed windows at various outside
Outside Air
Inside Humidity
at 20ºC (68ºF)
–30º or below
15 percent
–30º to –24º
20 percent
–24º to –18º
25 percent
–18º to –12º
35 percent
–12º to 0º
40 percent
If can be very difficult to accurately
measure and maintain the recommended humidity levels. A simple
Keeping the Heat In 8 Operating Your House
approach is to let the house become
your indicator. If condensation starts
to appear on the indoor face of any
double-glazed windows (except those in
the kitchen and bathroom), you have
found the balance point. Occasional
condensation does not pose a problem.
Excessive condensation or frosting is an
indication that you should reduce
moisture production or reduce humidity levels by increasing ventilation.
Increasing Ventilation
If you still have too much condensation
even after reducing moisture production, or your problem is one of air
quality, you will have to increase ventilation. There are several ways of doing
this; the best method will depend on
your house, the degree of the problem
and your preferences.
• A simple solution may be to turn on
kitchen and bathroom fans more
often, especially when those rooms
are used. A simple timer switch will
turn the fan off automatically to prevent excessive ventilation.
• If you do not have ventilation fans,
have them installed. It is worthwhile
buying quieter fans since they tend to
be used more regularly. Make sure
that the fan installation incorporates
air-sealing measures.
Fresh-air duct to the cold-air return
• Advanced, high-efficiency combustion appliances are ideal for airtight
houses. This creates far fewer problems than conventional appliances,
and at the same time, increases
energy-efficiency benefits.
• Open windows as needed. Windows
that are open on either side of the
house or on different floors will help
ensure better circulation. It is harder
to control the rate of ventilation by
this method, however.
• If the need for ventilation air supply
and distribution is great, a central
ventilating system can be installed.
A relatively inexpensive and effective
technique involves connecting a
fresh-air duct to the return-air
plenum of a forced-air system. Fresh
air is drawn in by the suction of the
furnace fan, mixed with house air
and preheated by the furnace. Open
the damper in the fresh-air duct just
enough to prevent window condensation. It will have to be adjusted
periodically through the winter.
Alternatively, you can install a
Heat recovery ventilators consist of:
1) collection and exhaust of stale,
moist air
2) supply and distribution of
fresh air
3) heat exchanger to recover
some of the heat from the
outgoing air
motorized damper operated by a
humidistat control. It will open the
damper only when the house
becomes too humid.
• There are other types of whole-house
ventilation systems that include
exhaust and/or supply fans. These
systems are for very tight houses that
require a great deal of ventilation.
The air must be distributed throughout the house and in a way that
maintains comfort levels. The system
should not create strong negative or
positive pressures in the house. This
means that the inlet and outlet air
supply has to be in balance.
Keeping the Heat In 8 Operating Your House
There are many appliances that
can compete for household air.
• Some systems are designed with the
exhaust fan in the attic and several
ducts pulling air from the kitchen
and bathrooms. Many central ventilation systems use a heat recovery
ventilator that typically recovers
70 percent of the heat from the
exhaust air and transfers the heat to
the incoming air or to the hot water
supply. Central ventilation systems
should be designed and installed by a
Backdrafts or spillage may be caused
by competition for air. For example, a
roaring fireplace, a powerful kitchen
ventilator, a barbeque range or even a
clothes dryer vented to the outside can
exhaust air from the house. If the house
is too tight, this can cause air to be
pulled into the house through the chimney or vent, resulting in backdrafts or
Some of the signs of combustion air
problems include the following:
• back-puffing of the furnace, indicated by soot or staining around the
air intake;
• unusual odours from the combustion
• difficulty starting or maintaining a
fire; and
Combustion Air
• the house’s occupants experience
frequent headaches or nausea.
Furnaces, fireplaces, wood stoves and
any other fuel-burning appliances also
require air for combustion and for diluting and exhausting the products of
combustion out of the house. If there is
not enough air, it is possible that the
chimney or flue could backdraft or spill
dangerous gases into the house.
The ideal solution is to remove the
source of the problem. If you are replacing your heating system anyway, consider buying a system that uses little or
no combustion and dilution air from
inside the house (e.g., a mid- or highefficiency heating system, an integrated
heat pump system).
Fireplaces are one of the worst culprits
for robbing household air. This can be
minimized by installing an outside air
duct to the firebox and tight-fitting
glass doors. Otherwise, a window
should be opened slightly when you
operate the fireplace.
Oil and gas furnaces may require a free
and unobstructed supply of outside air.
The size and type of ducting system will
vary according to the type of fuel and
the location and heating capacity of the
appliance. Obtain specific information
on all aspects of combustion air supply
systems from your local regulatory
authority, fuel supplier or heating
contractor before work begins.
Carbon monoxide (CO) detectors are
available at most hardware stores.
Properly installed, these detectors will
help protect occupants from accidental
asphyxiation due to a failure or malfunction of combustion appliances or
the penetration of automobile fumes
from an attached garage. It is recommended that they be installed in any
home with combustion appliances (fireplace, wood stove, fuel-burning furnace)
or an attached garage.
Care should also be taken to prevent
fumes from automobile exhausts penetrating the home from an attached
garage. Garage doors should always be
open before a car engine is turned on
while inside a garage.
Keeping the Heat In 8 Operating Your House
The whole, it is said, is
greater than the sum of its parts. In no
place is this more true than in your
household. The tips below are worth
their weight in fuel.
Rugs and Curtains
A rug on any floor over a cold part of
the house (a garage, a cold cellar or
even a coolish basement) will help to
insulate. This will not reduce heat loss
very well, but it will make the floor
feel warmer.
Despite all of the other work you have
done to keep the heat in, your windows
still represent a weak link. However,
with proper design and use of window
insulation, you can benefit from solar
gain during the day and lessen heat loss
at night. In the winter, shut your curtains to reduce heat loss once the sun
has gone down and open them during
the day. During the summer, keep
curtains and windows closed during the
day to help prevent overheating.
Using lights efficiently – and using
efficient lights – will help you achieve
even greater savings. Lights left on
unnecessarily, for example, will only add
to your energy costs. Lighting only a
specific work area (task lighting) allows
a reduction in general lighting levels and
will save energy.
All appliances can be used more efficiently. For example, be careful not to
leave the refrigerator and freezer door
open longer than necessary or leave electric kettles boiling.
There are also a variety of new light
technologies available that are ideal for
homes. Compact fluorescent bulbs are
pencil-thin fluorescent tubes bent into a
“U” shape to reduce their size; attached
to a regular screw-in base, they are ideal
for task-lighting purposes. A 15-W
compact fluorescent bulb lamp may
replace a 60-W incandescent bulb and
give you 10 times the life span.
Incandescent lights with halogen (parabolic aluminized reflector, or PAR,
lamps) are perfect for track lighting,
heat lamps or exterior floods, and can
cut energy use by 30 to 50 percent
compared to regular incandescents.
When buying a new major appliance,
take the time to compare the rating of
its energy use. The EnerGuide rating
provides the monthly energy consumption in kilowatt-hours for that particular
model. These ratings are clearly listed
on the EnerGuide labels of refrigerators,
freezers, ranges, dishwashers, clothes
washers and clothes dryers and can be
used to compare one model to another.
Alternatively, you can refer to the
EnerGuide Directory, available from
Natural Resources Canada, which lists
the rating of all the models currently on
the market. Even though energy-efficient
appliances may cost more, paybacks
are generally very attractive.
Keeping the Heat In 8 Operating Your House
General Maintenance
Once you have your house operating
efficiently, it is important to keep it that
way. Make a maintenance schedule and
check to make sure the energy-saving
measures you have initiated are working
for you. Keep an eye on your heating
system and perform regular maintenance.
Check for signs of moisture damage or
structural deterioration, and take immediate action if you locate any trouble
spots. It is a good idea to inspect your
attic during the cold months. Extensive
frost buildup is a good indication that
you have a moisture problem.
Do not forget – if you look after the little things, the heating bill will look after
itself. Make sure your weatherstripping
is in place and functioning as it should.
Check any caulking you have applied
for cracks, and recaulk as necessary. It is
important to locate and remedy small
problems and not give them a chance to
become large problems.
These simple measures will help you
save energy and leave you with a
healthier, happier home!
9 Dollars and Sense
Keeping the Heat In
At some point, most homeowners
hire a contractor for repairs, retrofit or
renovation work. Even ardent do-ityourselfers hire a contractor for work
that requires special tools, equipment
or expertise.
Whether you plan to hire someone for a
specialized part of the job or for the
whole retrofit, you will want to ensure
that you are satisfied with the results.
Many of the tips in this chapter will save
you time and money even if you do all
the work yourself. By following a few
simple guidelines, you will ensure that
the work goes smoothly, that it meets
your expectations and that you get what
you are paying for.
• Be an informed consumer.
• Accompany contractors when they
inspect the work.
• Establish a realistic schedule.
• Shop around and compare.
• Get a permit if you need one.
• Provide clear instructions.
• Get a written quote.
• Use a contract.
• Monitor the job.
Keep Informed
The housing renovation industry is one
of the fastest growing industries in
Canada, accounting for more than half
of all residential construction work. It is
a complex industry that includes general contractors and many different specialty trades. Like any other industry,
housing renovation is constantly changing as businesses and regulatory agencies
respond to changing market conditions
and consumer demands. The industry
is also highly subject to local conditions
such as availability of materials and
general level of construction activity.
Understanding these factors will help
you to choose the right contractor for
the job.
The following are some of the many different types of contractors who specialize in various aspects of retrofit work:
• Basement damp-proofing and foundation specialists work with concrete
and masonry to repair, damp-proof
and insulate foundations.
• Blown-in insulation installers use
specialized equipment to blow cellulose or mineral fibre insulation into
wall cavities or attics.
• Spray-on insulation installers use
specialized equipment to spray foam
or cellulose insulation.
• Carpenters are the generalists of the
construction field. They will frame
and insulate walls from the interior or
exterior and install the air and vapour
barrier. Often, they will also install
attic insulation, wood siding,
windows and doors.
• Siding specialists are often dealerinstallers for one type of vinyl, steel
or aluminum siding. Sometimes
their business combines siding with
soffit and fascia installation or with
window and door installation.
• Roofers will repair roofs and replace
elements such as flashing and shingles. They may also insulate the roof
from the exterior.
• Window and door installers are
often dealer-installers for one or
more products. In the case of storm
windows, they sometimes assemble
custom-sized units from components
supplied by the manufacturer.
• Air-sealing specialists concentrate on
tightening the air barrier throughout
the house, using caulking and weatherstripping. They will often test the
house airtightness before and after
the work, using a fan-door apparatus.
• Some heating contractors are
trained in tune-up methods that
go beyond regular furnace cleaning
and maintenance.
Keeping the Heat In 9 Dollars and Sense
Dollars and Sense
• Electricians, plumbers, drywallers,
finish carpenters, tile setters, painters
and decorators may also be involved
in a retrofit project.
there is a scramble to “close in” buildings
before the snow falls. The fall may not be
the best time to look for a contractor to
undertake an exterior retrofit.
• General contractors are the band
leaders of the renovation field. They
orchestrate and direct all the other
trades, but they usually employ their
own framers and finish carpenters.
If you are hiring one or more tradespeople, then you are acting as your
own general contractor on the job.
Labour strikes that affect new construction also affect the renovation field.
Material shortages can also upset schedules and the normal flow of work.
Scheduling Appropriately
Seasonal and local conditions will
affect the availability of contractors and
materials. Being aware of the conditions
in your area will help you to schedule
your work for the best time. Many
tradespeople work in both new construction and retrofit projects. If there is a
new-construction “boom” on in your
area, then fewer contractors will be
available for smaller retrofit jobs. The
construction field is seasonally dependent. When the season has been busy,
Smart scheduling, particularly for smaller
jobs, can make the job run smoothly
and save you a lot of money. Make use
of seasonal and local conditions to order
materials and hire contractors in the offseason when materials are on sale and
contractors are not charging a premium.
Generally, winter is the slow season in
construction but ideal for interior work.
An early spring start for outside work
will give you a better choice of contractors
and lower prices. Some materials such
as insulation are subject to seasonal sales
as manufacturers and building-supply
houses clear out last year’s inventory.
Comparison Shop
Retrofitting can be a very good investment, but it is still important to get the
most for your money. Both the price of
materials and the rates of contractors
can vary considerably. It almost always
pays to comparison shop before you
go ahead.
The renovation and retrofit industry is
known for a high turnover of businesses.
Knowing what to look for can help you
select contractors who are serious about
their business. Conditions will vary
among provinces and communities,
but it is good practice to look for the
following certifications and credentials:
• Business licence: All provinces
license companies that sign contracts
in the home. Check with your
provincial department of consumer
affairs. (Some municipalities also
require a business licence.)
Check with your local building-supply
house that services contractors. When
there is a shortage of materials or a construction boom, it may pay you to postpone your work a few months.
Keeping the Heat In 9 Dollars and Sense
• Trade membership: Many types of
contractors have their own trade associations; many heating contractors
belong to the Heating, Refrigerating
and Air Conditioning Institute of
Canada (HRAI), and the National
Energy Conservation Association
(NECA) is the association whose
members retrofit building envelopes.
The Canadian Home Builders’
Association (CHBA) has renovation
councils in many provinces which
represent general renovation contractors. Association membership is an
indication to the consumer that the
contractor is concerned about the
quality of work performed by its
• Better Business Bureau: Local
offices of this organization maintain
records for any complaints against
• Technical qualifications: In some
provinces, tradespeople such as
electricians, plumbers and heating
contractors are required to have technical certification as well as a business
licence. In addition, technical update
courses are offered by various associations for their members. Check with
the association in your area to find
out what technical qualifications
apply. Ask prospective contractors
what qualifications and technical
education they and their workers
possess and how regularly they
update them.
• Insurance: Contractors should be
insured for their business and the
work they do on your home. This
should include public liability, property damage and any damage within
the first year after completion of
the work.
• Warranty: Contractors should always
provide a warranty or guarantee on
the work performed. In some cases
the warranty is provided solely by the
contractor; in other trades it is
backed by the trade association or is
third-party insured.
• Track record: The best recommendation for any business is a satisfied
customer. Ask for recommendations
from friends and neighbours and
check out recent work performed by
the company.
To find the right contractor, start with a
list of those recommended by your
friends, other tradespeople you have
dealt with or building suppliers. Then
make sure they are experienced with the
type of work you’re proposing and that
the size of your job is suited to the scale
of their business. A large general contractor who did a successful major renovation for your friends may not be the
right choice for a small attic retrofit.
Finally, check to see how busy they are;
you don’t want to be last in line for a
contractor who’s overbooked.
As you narrow down the list, you should
end up with at least three contractors
whom you will ask to quote on the job.
Permits, Codes and Standards
While you are at the planning stage,
check with the building department of
your municipality to find out which
permits you’ll need. This varies from
province to province, but usually special
permits are required for any changes to
plumbing, heating and electrical wiring.
Building permits are also required for
any excavation, additions, changes or
alterations to the walls of a building.
The purpose of the permit process and
the related inspections is to ensure that
the work on your home meets provincial
or municipal requirements for health
and safety, and that it is structurally
sound. The National Building Code of
Canada, developed by the Associate
Committee on the National Building
Code, serves as a model for the
provinces, which have the authority to
regulate buildings. Membership on
Keeping the Heat In 9 Dollars and Sense
this committee includes architects,
engineers, academics, land surveyors,
municipal inspectors, builders and
consumers. Many provinces have adopted
the National Building Code in whole or
in part, and some have a separate code or
section of the code governing renovation
activities. In some cases the province
delegates some of the supervisory roles
to the municipality.
A building inspector can be a valuable
resource for your project. With their
many years of experience in the construction field, inspectors can often
provide valuable advice on quality of
workmanship, local construction
practices, suitable materials and other
concerns, in addition to ensuring that
your work meets the building code.
Codes will often state that products or
installation methods must conform to a
certain standard. There are three organizations that write standards and test and
certify products affecting residential
renovation work:
• CSA International is a non-government agency that prepares standards
and certifies products such as electrical fixtures.
• Underwriters’ Laboratories of
Canada (ULC) certifies mainly
products related to fire safety.
• The Canadian General Standards
Board (CGSB) is a government
agency operating as a national
standards-writing body.
Provide Clear Instructions
Whether you plan to hire just one subtradesperson or a general contractor for a
major renovation, it’s important to be
specific about the work to be done.
Without clear instructions to all concerned, misunderstandings can occur
and you may not get what you thought
you bargained for.
The amount of detail in your written
instructions will vary depending on the
size of the job. Remember, building
components are hidden from sight once
the job is completed, so it is important
to describe clearly what you want. For a
simple attic retrofit, you may need just a
set of written notes outlining the work.
This might include the area to be insulated, the amount and type of insulation
and RSI value to be achieved, and directions for installing the air barrier, vapour
barrier and any required ventilation. A
major renovation or retrofit may require
some or all of the following:
Giving clear instructions about what
you want and expect is important at
three different stages of the job:
• a site plan;
• Planning: Drawings and specifications may be required for your permit
application. Preparing written
instructions will also help you to
ensure that you’ve included all essential aspects of the job in your plans.
• elevations of the house exterior;
• Getting quotes: Clear directions
are necessary to obtain comparable
quotes with all the contractors
bidding on the same materials and
quality of work.
• Under contract: Including clear
instructions in the contract will help
to ensure that there are no misunderstandings while the work is in progress.
• floor plans;
• a cross section of the house;
• detailed drawings; and
• written specifications.
Your local building department can
advise you on what information is
required for the permit. In addition,
you should include instructions about
disposal of building materials, responsibility for permit applications, temporary
services (if needed) and other details for
major jobs.
Keeping the Heat In 9 Dollars and Sense
Get a Written Quote
For proper comparison, you will need a
number of quotes. Using your written
instructions will ensure that all the contractors are bidding on the same job.
Always insist on a written quote that
includes all the details in your set of
instructions. It’s also wise practice to ask
the contractors to supply two or more
references of previous clients with their
quote. When comparing quotes, doublecheck to make sure that the contractor
understood the instructions; a very
low bid may mean that the contractor
misunderstood the work or substituted
lower quality materials and workmanship.
Take the time to evaluate all the quotes
and to check the references. Do not let
anyone pressure you into signing a contract before you are ready.
Use a Contract
Once you’ve chosen a contractor, insist
on a written contract. The contractor
may have a standard printed form but it
should be used only as a starting point
for negotiations.
While there is no such thing as a standard contract, provincial legislation may
specify what must be included in a contract for it to be effective. Check with
your municipal or provincial consumer
affairs office. The guidelines below provide an example of what is likely to be
• Your name and address, the contractor’s name and address, the contractor’s
full company name, phone number
and name of the company’s signing
• A detailed description of the work to
be done under the contract. (Include
your written instructions and any
plans and specifications.)
• An itemized price for the work and
the terms of payment.
• A statement of any warranty or guarantee on the work to be performed.
• Specific dates for starting the work
and completing it.
• Signatures of both parties, with each
retaining an original signed copy of
the contract.
For smaller jobs the contract need
not be a complicated document, but
it should include all the items listed
above. The amount of detail in the
contract should increase with the size
of the job. For major renovations and
retrofit jobs, a full set of contract
documents should be prepared, including plans and detailed specifications.
These documents should be checked
by your lawyer.
Take the time to review the contract
carefully (including all the fine print)
and make sure that you understand
everything before you sign it. A serious
contractor will appreciate your thoroughness and will not mind waiting a
day or two.
Read the fine print carefully. Some firms
have worded their contracts in such a
way that they are not responsible for any
problems following the work. Such
clauses usually imply that any subsequent problems (e.g., peeling paint,
cracks) are related to “hidden construction defects” that existed prior to the
retrofit work. This may not necessarily
be the case. Stroke out these clauses
before you sign.
All verbal agreements should be written
into the contract. If there are minor
changes you wish to make, write them
in on both copies of the contract. They
will be valid if initialled by both you
and the contractor.
Make Sure You Have Recourse
Insist on a written warranty as part of
the contract. Responsible contractors
will guarantee their work and assume
responsibility for problems that could
develop later as a result of their work.
Keeping the Heat In 9 Dollars and Sense
Be wary when asked to pay in advance
or in cash to a salesperson rather than by
cheque or money order to the company
itself. If a downpayment is required,
keep it as small as possible. Usually the
first payment is made only on delivery
of materials to the site. Advance downpayments are restricted to situations
where the contractor has to place an
advance order for large quantities of
special materials (such as custom-made
windows). Payment schedules should
be tied to work actually completed and
not to arbitrary dates. Any provisions
for holdbacks should be written into
the contract.
You should also be aware that if your
contract is sold to a third party, such as
a finance company, you are obligated to
it regardless of any complaints you may
have about the quality of the work.
Take Extra Precautions with
Door-to-Door Salespeople
Be especially careful when dealing with
firms that sell their services through
door-to-door salespeople. Fly-by-night
and unreliable businesses are more likely
to depend on door-to-door sales. Insist
on seeing the sales representative’s card.
Check if the company has a permanent
office location that you can call if
problems occur with the product or
Never sign on impulse. Ask the salesperson to give you a copy of the contract so
you may think it over; if this request is
refused, it’s probably because you are on
the verge of closing a bad deal. Shop
around to compare quality and prices.
Do not be pressured into buying.
If you sign a contract in your home,
remember that all provincial statutes
regulating direct (door-to-door) sales
have a so-called “cooling off ” provision.
This gives you the right to cancel a contract signed with a door-to-door salesperson within a specified number of
days. The number of days varies from
province to province; check with your
provincial consumers’ bureau. There
may be other instances where you can
cancel your contract after the coolingoff period is over. Again, check with
your provincial consumers’ bureau.
required to keep track of the work
and resolve any problems as they arise.
The payment schedule should be tied
to work actually done, and not to
predetermined dates. Where permits
are involved, you may wish to tie in
progress payments to successful passing
of the various building inspections
during the course of the job.
Your final payments should be made
only some time after the work is totally
complete. In most provinces, legislation
permits you to retain a set percentage of
the total cost of the work for a specific
period of time. The purpose of this
holdback is to help limit your liability
should a contractor fail to pay suppliers,
workers or sub-trades. The legislation
varies from province to province. Your
provincial consumers’ bureau will be
able to provide you with details.
Monitor Performance
When you hire a contractor, it is your
responsibility to make sure that the job
is done on time and on budget. For
smaller jobs, this may simply mean
being on hand to make sure that
materials are the same quality and type
as stated in the contract and that the
work method follows your written
instructions. For larger jobs, a daily
meeting with the contractor may be
Keeping the Heat In
Additions ......................................................................105
Attics .........................................................................55-63
Air barriers
general ......................................................10, 14, 32, 38
materials ................................................................32-38
Attic hatches....................................................................52
Air-leakage control
attics ...........................................................57-58, 59, 65
attic hatches ..........................................................52, 58
basements ...................................................................48
cathedral ceilings.........................................................68
chimneys.........................................................51, 58, 62
chutes .........................................................................52
detection of air leaks....................................................46
electrical outlets ..........................................................50
fixtures............................................................55, 63, 66
flat roofs .....................................................................68
garages ..........................................................83, 88, 103
general...............................................3, 14-15, 22, 44-53
header area..................................................................83
overhangs ............................................................89, 104
plumbing penetrations ................................................88
trim areas....................................................................50
walls .............................................58, 66, 72-73, 99, 100
windows.................................................51, 52, 106-111
wiring ...................................................................55, 57
Baffles .............................................................................60
Basements ..................................................................74-91
Cathedral ceilings.......................................................68-69
Caulking...................................................33-35, 42, 48-49
Chimneys .............................................................51-52, 58
Codes and standards ...........................................5, 126-127
Cold cellars........................................................83, 88, 104
Combustion air............................................14, 17, 45, 121
Common wall .................................................................65
Condensation (see Moisture problems)
Contracts...............................................................127, 128
Crawlspaces ................................................................90-91
Damp-proofing ............3, 16, 59, 60, 62, 63, 64, 69, 71, 75
Doors ....................................................23, 36-38, 112-113
Dormer windows.............................................................66
Dropped ceilings .............................................................71
Electrical outlets ...................................................35, 38,50
Air sealing (see Air-leakage control)
Fireplaces...........................................................17, 45, 116
Air and vapour barriers ..................................20, 49, 56, 60
Flashing.................................................19, 55, 78, 81, 101
Flat roofs....................................................................68-69
Frost heave.....................................................77, 84, 90, 91
Keeping the Heat In • Index
Garages .............................................................83, 88, 103
Moisture barriers .......................................................20, 39
Gaskets...........................................................35-36, 50, 57
New construction ..........................................................105
Half storeys................................................................64-66
Open foundations............................................................92
Health and safety .............5, 17, 40-43, 63, 79, 84, 118-121
Overhangs ...............................................................89, 104
Heating system ........................3, 17, 22, 45, 115, 118, 121
Quotes ..........................................................................127
Heritage buildings ...........................................................22
Permits ...................................................................126-127
Hiring a contractor..........................5, 53, 93, 104, 124-129
Recessed light fixtures ..........................................55, 63, 66
House as a system ....................................4, 10, 21, 45, 114
RSI value (R-value) ................11-13, 26-31, 60, 67, 101-102
Humidity (see Moisture)
Sealants (see Caulking)
attics ..........................................55, 60-63, 65-67, 70-71
basements ..............................................................76-89
concrete slabs ..............................................................93
crawl spaces............................................................90-91
general..............................................................11-12, 22
half storeys.............................................................64-65
hot water heaters ................................................116-117
materials ................................................................25-42
open foundations.........................................................92
walls ......................................................................96-99
Vapour barriers ..........................................................20, 39
Lighting ........................................................................122
attics ...........................................................................55
basements ...................................................................75
crawl spaces.................................................................90
general ............................................9-10, 18-19, 118-121
sources ................................................................18, 118
walls ...........................................................................95
windows ...................................................................107
attics ...............................................................58, 63, 64
combustion air ..........................................................121
crawl spaces............................................................90-91
house.......................................................15-17, 118-121
Weatherstripping...................................36-38, 52, 108, 112
Wind barriers ............................................................10, 14
insulation ...........................................................108-109
new windows ............................................................111
storm windows .............................................23, 109-111
Wiring ................................................................55, 66, 85
Keeping the Heat In
Need More Information?
Order Free Publications from
the OEE
The Office of Energy Efficiency (OEE)
of Natural Resources Canada offers
many publications that will help you
understand home heating systems,
home energy use and transportation
efficiency. These publications explain
what you can do to reduce your energy
use and maintenance costs while
increasing your comfort and helping to
protect the environment.
Renovating Your Home
Fact sheets are available on air-leakage
control, improving window energy
efficiency and moisture problems.
Before you renovate, consider contacting
an energy advisor who will perform an
energy evaluation of your home and
provide expert unbiased advice. Our
telephone operators can connect you
with an advisor in your local area.
EnerGuide for Home Heating
and Cooling
Every New House Should Be
This Good
If you are interested in a particular
energy source, the OEE has booklets on
heating with electricity, gas, oil, heat
pumps and wood. Other publications
are available on heat recovery ventilators,
wood fireplaces, gas fireplaces, air conditioning your home and comparing
home heating systems.
R-2000 homes are the best built, most
comfortable homes in Canada, and they
use up to 50 percent less energy than
conventional dwellings. R-2000 homes
feature state-of-the-art heating systems,
high levels of insulation and wholehouse ventilation systems that provide
continuous fresh air to all rooms.
Subject to quality assurance checks
during the construction process, once
completed, R-2000 homes are certified
as being energy efficient.
EnerGuide for Choosing the Most
Energy-Efficient Products
When shopping for household appliances, office equipment, lighting products, and windows and doors, consult
the OEE’s series of Consumers’ Guides.
They’ll help you know what to look for
when it comes to energy efficiency.
The EnerGuide label, which is affixed
to all new major electrical household
appliances and room air conditioners,
helps you compare the energy ratings
of all models sold in Canada. EnerGuide
ratings are also listed in the OEE’s
annual directories of major electrical
household appliances and room air
Keeping the Heat In Need More Information?
Buying, Driving and Maintaining
Your Car
To receive any of these free
publications, please write or call:
For information on vehicle fuel consumption, look for the EnerGuide label
that appears on every new automobile,
van and light-duty truck for sale in
Canada. It helps you compare different
vehicles’ city and highway fuel consumption ratings and estimated annual
fuel costs. You can also check the OEE’s
Fuel Consumption Guide, produced
annually, which provides the same
information for all vehicles. The OEE’s
EnerGuide for Vehicles Awards also
recognize the vehicles with the lowest
fuel consumption in different categories.
Energy Publications
Office of Energy Efficiency
Natural Resources Canada
c/o St. Joseph Communications
Order Processing Unit
1165 Kenaston Street
PO Box 9809 Station T
Ottawa ON K1G 6S1
Also available is the OEE’s Car Economy
Calculator, a fuel log that helps you calculate your fuel consumption and savings.
The OEE’s Auto$mart Guide provides
detailed fuel efficiency information and
offers tips on purchasing, operating and
maintaining personal vehicles.
Tel.: 1-800-387-2000 (toll-free)
National Capital Region: 613-995-2943
Fax: 613-740-3114
TTY: 613-996-4397 (teletype for the
Please allow three weeks for delivery.
Publications can also be ordered or viewed
on-line at the OEE’s Energy Publications
Virtual Library:
Keeping the Heat In
Keeping The Heat In
Keeping the Heat In
Natural Resources Canada’s Office of Energy Efficiency
Leading Canadians to Energy Efficiency at Home, at Work and on the Road
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF