A project of Volunteers in Asia --

A  project  of  Volunteers in  Asia --
A project of Volunteers
in Asia
Construction Reference Manual
-by Donald Batchelder et. al.
Published by:
The Experiment in International Living
Kipling Road
05301
Brattleboro, Vermont
USA
Available from:
same as above
Reproduced by permission.
Reproduction of this microfiche document in any
form is subject to the same restrictions as those
of the original document,
I
b
'1 1
For The Use Of
Local
aterials
In Construction
THE KITEREDDE
CONSTRUCTION
INSTITUTE /UGANDA
THE EXPERIMENT IN
INTERNATIONAL LIVING
DONALD BATCHELDER
ROBERT E. CAIOLA
STANTON W. DAVENPORT
A Sourcebook For The Use Of
aterials In Construction
Copyright @ 1985
by The Experiment in International Living
Kipling Road
Brattleboro, Vermont, 05301
U.S.A.
Grant assistance was provided by the Australian High Commission,
Nairobi, Kenya; the Canadian High Commission, Nairobi; and
Catholic Relief Services.
ii
A Sourcebook FOPThe Use Of
Local Materials In Construction
TRE KITEREDDE CONSTRUCTION INSTITUTE
and
THE EXPERIXRNT IN INTERNATIONAL LIVING
KITEREDDE, UGANDA
DONALD BATCBELDER, ROBERT E. CAIOLA, STANTON W. DAVENPORT
THE EXPERIMENT PRESS
1985
iii
TABLE OF CONTENTS
INTRODUGTION ....~................*....................*..............
1
LOCAL BUILDING MATERIALS ............e...*.........
4
Mud Bricks ..................................................
Raw Materials ...............................................
Clay for Brick-Making....................................
Testing of Clays .........................................
Clays in Southern Uganda .................................
Digging Clay for Brick-Making ............................
Processing the Clay ......................................
5
5
6
7
8
9
10
Bricks ......................................................
Brick Size...............................................
Moulds ...................................................
Calculating Brick Quantities .............................
Table Method of Hand-Moulding Bricks and Blocks ..........
Drying and Stacking Bricks and Blocks ....................
10
10
11
12
12
14
Burning of Bricks in a Country Kiln .........................
Large Country Kilns ......................................
Small Country Kilns ......................................
Kiln Construction ........................................
Kiln Operation ...........................................
Kiln Fuels ...............................................
15
15
15
17
18
20
Selection and Identification of Wood and its Usage ..........
Wood for Special Purposes ................................
Timber Species Most Commonly Used in Uganda ..............
Softwood Identification ..................................
Hardwood Identification..................................
Wood 'Treatment...........................................
Drying and Stacking Wood .................................
20
21
21
21
21
22
22
-RI
(ZHAPTER11
BASIC BUILDING COMPONENTS ................................
25
Introduction..I..................................*..........
25
Foundations.................................................
Laying Out a Foundation ..................................
Concrete Perimeter Foundation ............................
25
27
28
Excavating, Pouring, Forms ..................................
Pouring Concrete .........................................
Concrete Slab Floors .....................................
Cast in Place Concrete Piers .............................
Wo.odPoles ...............................................
29
30
31
32
33
V
BASIC BULIDING COMPONENTS (continued)
Vi
Types of Walls ...............................................
Mud or Adobe Brick ........................................
Mud Block .................................................
Burned Bricks .............................................
Concrete Block ............................................
Stone Walls ...............................................
Corrugated Iron ...........................................
Veneer Walls ..............................................
Fise or Rammed Earth ......................................
Common Mud Walls ..........................................
Thickness and Height of Walls and Gables ..................
34
34
35
35
35
36
36
36
36
36
37
..
Bricklaying: Solid Walls and Joints in Brickwork ..........(I
Importance of Mortar ......................................
Meaning of Brickwork ......................................
Size of Mortar Joints .....................................
Bond in Brick .............................................
Types of Bond in Brickwork ................................
Terms Used in Bonding.....................................
39
39
39
39
40
40
41
Roof Framing .................................................
Instructions for Building a Gable Roof ....................
Eaves .....................................................
Flat Roof .................................................
Roof Trusses ..............................................
Roofing Materials .........................................
42
42
44
44
45
46
Windows and Doors .....*.........*.....................*......
48
CEAPTER III ALTERNATIVE BUILDING MATERIALS AND TECHNIQUES.............
53
Introduction ....*......*....*................................
53
Local Material Mixes .........................................
Concrete Foundation Using Local Materials .................
Mortar Cement .............................................
Damp-Proof Course .........................................
Foundation Mortar .........................................
Interior Plastering .......................................
Exterior Plastering .......................................
Concrete for Ring-Beam ....................................
Concrete for Floors .......................................
Mixing Alternative Cements ................................
54
54
54
54
54
54
54
55
55
57
Anthill Kiln and Anthill Clays ....*....................a.....
57
Locally Available Paints and Paint Colours...................
Local Paint Brush .........................................
60
61
CHAPTER IV
BASIC MATHEMATTCS FOR CONSTRUCTION........x.............. 63
Fundamental Ideas in Geometry .............................. 63
Formulas and Examples ................................... 64
Summary of Formulas ...................................... 67
Concrete Mixes and Calculation of Cubic Yardage............
68
Calculating Strength for Wooden Beams....................... 70
Symbols and Abbreviations ..,..*............................
74
Useful Numbers ..............................................
Weights .................................................
Weights of Substances...................................
Linear Measurement ......................................
Area Measurement ........................................
74
74
75
75
75
PLANNING AND MANAGEMENT .................................
77
Introduction..,.....,..........................e...........
77
Securing Authority .........................................
Planning...................................................
General Building Calendar ...............................
77
78
78
Policy.....................................................
Seeking Advice ..........................................
79
79
Selecting a Site .....................................*.....
79
Business Detail ............................................
Orders ..................................................
Contracts ...............................................
Accounting ..............................................
Care of Materials .......................................
80
83
83
84
84
Labour .....................................................
Labour Agreements .......................................
Labour Relations ........................................
Supervision of Labour ...................................
85
86
86
88
Calculating Simple Interest ..........".....................
89
CHAPTEXV
CHAPTER VI
BASIC SKILLS AND OCCUPATIONAL PROFILES..................
91
Introduction............................................... 91
Occupational Profiles ...................................... 91
Performance Standard Key ................................... 93
Masonry Task Listing ....................................... 93
Carpentry Task Listing ..................................... 97
Cabinet-Making Task Listing ................................ 99
Drafting Task Listing ...................................... 100
APPENDIX I
GLOSSARY ..... ......*...................................... 103
BpPENDIXIIREIrERENcESANDAcRNowLEDGEEIENTS
.............*............. 111
ENDLEAF ............................................................... 113
The Kiteredde Construction Institute ......................... 113
The Experiment in International Living ....................... 113
1
Viii
INTRODUCTION
Housing and shelter are fundamental needs throughout the world, and
each country and cultural group attempts to meet its own needs by designing
structures which are appropriate to the climate, conditions and materials
available. In modern times, the advent of mass production, long-distance
transport and vigorous marketing systems have made possible, in some cases,
the importation and movement of housing and building materials from one
region or continent to another.
In many cases, however, the surplus capital for the purchase of manufactured products and processed building materials does not exist, and many
countries cannot afford to expend precious foreign exchange on imported
cement, steel reinforcing bars, metal roofing sheets and other materials
for construction, in view of the manv pressing needs in agriculture,
health, education, industrial development and other important sectors.
At the same time, many of these same countries do not have the raw
materials, capital or capacity to produce sufficient quantities of building
materials for national needs and at prices which are within the reach of
ordinary family budgets,
Many excellent sourcebooks and technical manuals have been published on
the subjects of low-cost housing, the use of local materials for buildings,
the design and ste?-by-step construction of houses, clinics, schools and
public and commercial structures, as well as agricultural sheds and storage
facilities. It is not the purpose of this small bock to duplicate the good
work which has already been done by others, but rather to take a look at a
specific area of the world, and to address actual construction issues from
the perspective of several years of direct hands-on experience, and perhaps
most important of all, from a slightly different premise,
Simply stated, the premise underlying this volume is that a significant
gap exists in construction literature, which is that most of the technical
manuals we have studied assume a certain level of availability of manufactured materials. The purpose of this manual is to provide a basic
understanding of the ways in which clean, durable structures can be built
with local materials and in the total or near-total absence of manufactured
materials.
Expanding populations require additional housing far beyond the capacities of many countries to provide. It is estimated that in some African
countries,,the number of housing units will have to double by the year
2000, simply to stay even with the demand. While this may be good news for
the construc.tionindustry, it places enormous strains on financial reserves, policy makers and natural resources of a nation. It appears likely
that few developing nations will have the financial strength in the next
two decades to enable them to provide adequate housing for their citizens,
unless a coordinated effort is made to promote self-help housing construction, to learn how to make good use of locally available materials,
and to support the technical training of youth and adults in basic building
techniques and the practical elements of extracting, adapting and using
local materials. The customary system of importing manufactured products
and processed materials will not solve the problem of providing adequate
housing for the vast numbers who need it now, and for the masses of
children currently growing to adulthood who expect to have families and
homes of their own.
In 1979, The Experiment in International Living, a private voluntary
organization, and the Bannakaroli Brothers, an African Catholic order, with
headquarters in Kiteredde, Rakai District, llganda,jointly planned a
vocationai training center which was specifically designed to train young
men and adults in construction skills using locally-available materials.
The Kiteredde Construction Institute (KCI) was established in 1980.
Initial funding support was provided by the Congress of the United States,
and administered by the U.S. Agency for International Development (USAID)
(1979-81). Additional support was provided by the Canadian International
Development Agency (CIDA), the Australian High Commission, Catholic Relief
Services, and The Experiment in International Living. Land, work space and
start-up facilities were provided by the Bannakaroli Brothers.
Training specialists from The Experiment worked side-by-side with the
technical and construction personnel of the Bannakaroli order in all phases
of planning and implementation of the project, from the design of the
curriculum to the actual construction of classrooms, dormitories and work
spaces. From the beginning, the emphasis of the program was on practical
skills development, learning by doing, the preparation of trainees for jobs
in the construction industry and in public works departments, and the
placement of each in wage-earning employment immediately upon graduation.
Were this volume intended to be a history of the Kiteredde Construction
Institute, it could include development-related narratives about the philosophy of the educational program and its impact upon attitudes towards
craftsmanship, standards and work; it could describe the training of young
men in the elements of small business management, and the subsequent formation of a number of small-business firms by graduates, which are now carrying out useful construction projects in Uganda; it could speculate on the
possible socio-economic ramifications of the fact that KC1 has over 500
applicants for the 25 spaces in each entering class; it could mention the
increasing volume of requests for KC1 to provide outreach, extension and
training services for others; it could include a description of the technical assistance KC1 personnel have provided to other development programs
in Uganda, such as well construction and basic skills training; or it could
tell about the progress made in opening up new farm acreage to move the
institution towards self-sufficiency; or could try to explain why employers
in public works offices and in the construction industry request more graduates to fill jobs than the institution can provide.
But perhaps the single most relevant component of the program which
requires mention here is the Bannakaroli Brothers' knowledge of the use of
local materials for construction, their experience in practical applications, and in training others how to use them.
New construction and the building of new houses came to a virtual
standstill in Uganda in the 1970s. The construction industry lacked materials, and the state of the economy forced people to reach back to all
but forgotten materials and methods.
The Bannakaroli Brothers had worked for a number of years with the
excellent clays and other materials available in southern Uganda, and had
employed them in the construction of their own buildings, and in carrying
out construction assignments for others. This knowledge of brick, tile,
block and clay moulding; of efficient kilns and appropriate firing techniques; of masonry and carpentry; of tropical building design; of the use
of local materials to make mortar, paints, plasters and other necessary
elements of construction, in the absence of manufactured and imported materials, form the basic components of the training program at the Kiteredde
Construction Institute, and the basic contents of this manual.
3
I
c
CHAPTER
1
LOCAL BUILDING MATERIALS
Introduction
There are many problems plaguing the building industries in Africa and
in other developing regi.ons,in view of growing populations and demand for
housing. The high custs of importing materials, and of producing highquality building materials domestically, are perhaps the major constraints
to progress. In addition, local production of building materials in many
areas cannot keep pack with demand, particularly in rural areas where there
is limited access to urban factories and where transportation facilities
are limited.
A practical response to these problems is being carried out in southern
Uganda through the use of locally available materials. The contents of
this chapter provide introductory information about the techniques and materials being used by the Kiteredde Construction Institute, local area contractors and residents in building affordable houses and other structures.
Construction techniques in the area are primarily masonry-based, because of the excellent clays which are readily available. Houses are generally built with light-weight metal roofing (corrugated sheets) and conventional aperture treatments, with typical electrical and plumbing installations.
Not all problems have been resolved. Work is being done to address the
chronic lack of durable, light-weight roofing, made from local materials,
which will eliminate the expense of metal roofing. Locally produced cement
in Uganda, as in many other countries, is often of poor quality, and lime
as a bonding substitute, or as a supplement to save on the volume and cost
of cement, is rarely used, despite the availability of lime deposits in
many areas. This is primarily due to the cost of the equipment needed to
produce lime from extraction, and the systems to make it available in local
markets at reasonable prices.
In general, the use of local materials needs to be supported and reinforced to produce sufficient quantities of materials of adequate quality
to withstand the effects of climatic conditions which range from humid
rainy seasons to extremely hot dry seasons. Mud structures, mud and wattle
buildings, and locally produced bricks and blocks do not endure for many of
these seasons, and must be constantly patched and repaired.
A recent socio-economic study of four districts of Uganda offers some
insight into the general condition of housing in representative areas:
Kigezi, Masaka, Teso and Busoga. Of 2702 households sctrveyed,258 were
grass huts (9%); another 900 were round mud-and-wattle construction with
thatched roofs (33%); another 740 dwellings were rectangular mud-and-wattle
construction with thatched roofs (27%); there were 679 houses of mud-andwattle, rectangular in shape, with iron roofs (25%); and 117 rectangular
houses made of brick and block construction with iron roofs (4%).
Without going into a detailed analysis of these figures, it is safe to
state that a great volume of sub-standard housing ex'.sr,s
in Uganda as elsewhere, particularly in rural and village areas.
In response to the need for better housing at reasonable cost, this
chapter offers techniques of clay extraction and preparation; testing for
clay plasticity; basic standard brick and block sizes; moulding, drying,
stacking and storage of air-dried bricks and blocks; kiln construction;
fuels and firing techniques for kilns; wood identification and treatment;
and the uses of different kinds cf woods in construction.
Clearly, the emphasis on clays, and brick and block construction, in
this chapter is not entirely suitable for builders in regions where clay is
not readily available, but the approach to iderltifyingand making good use
of the materials at hand may be useful. Chapter III deals with alternative
building materials.
Finally, it is hoped that readers will be able to employ the techniques
outlined in this chapter, or adapt them to their own situations and materials, to build more attractive and durable structures, at lower cost, and
with lower repair and maintenance costs over the years. It is also hoped
that over time, contractors and the building industry in general will begin
to make better use of local materials to reduce construction costs and to
help bring clean durable housing within reach of everyone.
LOCAL BUILDING MATERIALS
Mud Bricks:
One of the world's most widely used
building materials is burnt brick.
Many countries have deposits of suitable clay, and good sources of local
fuels, so that no foreign exchange is
needed for the production of this
weli-proven building material.
Although highly mechanized production methods are used successfully in
many countries, these may be uneconomical where the rate of production
is low, and may be inadvisable where
spare parts, maintenance and service
are difficult to obtain.
dreds of years, although machinery is
also employed. Increasingly, local
builders and markets have indicated a
need to improve the quality of bricks
in many areas, and the growing demand
for housing construction has called
for new production facilities. The
most important areas of improvement
in order of priority are:
Improved hand-moulding systems to
shape bricks more accurately in areas
where slop-moulding is traditional;
A simple mixing and screening system for raw materials;
Thus in many developing countries,
labor intensive production methods
are more appropriate, and if care is
taken in production, can produce satisfactory bricks.
The development of a small-scale
kiln for firing the bricks.
Most bricks made in developing countries are moulded by hand, using traditio'nal techniques which in some instances may have been in use for hun-
The principal raw material used in
brick-making is called clay. Pure
clay has a property called plasticity, which means that it is a mate-
Raw Materials:
5
rial which can be made into a variety
of shapes by applying pressure. When
the pressure is removed, the plastic
material retains much of its new
shape.
Dry clay is not plastic. It must be
first mixed with water. When the wet
clay has been formed into a specific
shape, such as a brick, and then is
allowed to drv, it once again b:zcomes
hard 316 con-plastic. If, however,
the dry brick becomes wet again, the
clay becomes soft once more, and running water or rain will gradually
wash it away.
Rut clay has another important quality. If it is heated until it becomes red hot, it loses its ability
to become plastic (or to soften and
wash away in the rain) when it becomes wet. It is this last property
that makes burnt clay bricks so important fo; building houses, grain
stores and otiieragricultural structures, drainage ditches, factories,
and office, commercial and other
buildings.
Finally, the other most important
property of clay is that if it is
heated to a high enough temprerature,
and then cooled, the strength of the
material increases until it is much
stronger than the original unburnt
clay.
The clays used in brick-making are
not pure. They vary, not only in the
types of clays present, but also in
the types and amounts of impurities
that are present. The degree of purity, and kinds of impurities, vary
from one place to another, and also
vary according to the nearness of the
clay to the surface or its depth below the surface of the ground.
The type and amount of clay present,
and the type and volume of impurities
in it, determine whether or not good
quality bricks can be made. These
factors, the amount and kind of clay,
6
and the degree of purity/impurity of
the sample, determine the kinds of
problems one may encounter in trying
to manufacture strong durable bricks.
Variations in the quality of the clay
determine the proper water mixtures,
and affect the moulding and drying
process, as well as the proper firing
temperature and kiln-time needed in
order to produce high-quality bricks.
Thus, it is most desirable that clays
be tested for suitability and purity,
unless reliable testing has already
been done, or unless their properties
are well known from direct experience
and successful production. It is
particularly important that reliable
testing be carried out regarding both
the quality and quantity of the clays
available, if someone is planning to
establish a brick-making business, or
to invest money in clay extraction or
brick production.
Clay For Brick-making:
Clay for brick-making must satisfy a
number of requirements:
1. The deposit must be easily
available, which means there must be
access to the deposit so the clay can
be excavated using the facilities at
hand. At the same time, the clay deposit should be located within a reasonable distance of the people who
are going to buy or use the bricks.
2. The clay must be suitably
plastic when mixed with water, and
such mixing must be easily done using
the facilities available.
3. The plastic clay must be able
to hold its shape when moulded into a
brick? and must not warp, distort or
crack during the drying process.
4. The dried brick must be strong
enough to withstand whatever handling
is required during the production
process. For example, bricks at the
ground level under the weight of the
stack of bricks above them in the
kiln, must be able to withstand the
weight and pressure of the bricks in
the settings above.
5. The clay should be free from
harmful impurities such as limestone,
large stones and soluble salts. Limestone can cause the brick to burst
around the limestone particles after
it has been fired. Stones can cause
cracking in the bricks. Soluble salts
can cause harmful and unsightly deposits on the bricks after they are
fired. Limestone particles are usually white to grey in color, and may
be as small as a pin head in size to
as large as a groundnut, Larger
particles of limestone can be picked
from the clay, if there are not too
many of them, Soluble salts can usually be seen as a fine sugar-like or
crystalline deposit on the clay as
it drier..
6. The clay should have the two
qualities of (a> forming into an adequately durable brick as a result of
the firing process, and (b) not distorting or warping during firing. It
is important to know that different
clays require different temperatures
for adequate burning, and that different fuels, firing methods, and
kilns produce different temperatures.
Higher temperatures for hotter firing
require more fuel, and are therefore
more costly.
this shrinkage. A small amount of
shrinkage also takes place during the
firing process.
A brick made from a clay mixture with
less water is usually more dense and
stronger than a brick made from a
clay mixture with more water. During
the firing process the dense brick,
with less water in the clay, has more
surface particles of clay touching
one another, than is the case with
wetter clays. These pieces fuse together more readily, and tend to form
a stronger burnt brick.
Testing To Discover The Amount of
Clay In A Soil Sample:
1. The Shine Test:
Take a small handful of soil, and add
water to make a stiff mud. Then mix
thoroughly in the palm of your hand.
Open your hand and make a flat cake
out of the mixture. Slowly close
your hand around the cake, and watch
the mixture closely. The cake should
shine as your hand begins to close
and apply pressure. If not, add more
water and try it again. If the shine
disappears when you open your hand,
it means that the soil may have too
much silt or sand in it. If the
shine does not go away when you open
your hand, it should indicate that
your soil sample contains a high proportion of clay. (Figure 1.)
Wet clay shrinks as it dries, and the
shrinkage is in direct proportion to
the amount of water present in the
clay. Different types of clay require lesser or greater amounts of
water to make the clay plastic for
moulding , and to produce suitable
bricks for firing and use.
This quality of shrinkage during the
drying process is important to bear
in mind when making a brickmould, or
in having one made, because the size
of the mould must always be slightly
larger than the size of the final
burnt brick, in order to allow for
Figure 1
7
2. The Worm Test: (Figure 2.1
Wet a soil sample until is becomes a
stiff mud, moist but not watery. Roll
the stiff mud into a worm shape about
the thickness of a pencil, and about
10 cm long. Use the palm of your
hand to roll out the sample on a flat
hard surface. Carefully pick up the
worm of stiff mud with two fingers
holding it at one end. Hold the worm
parallel to the ground. If the worm
breaks off from its own weight, it
contains silt and sand. If the worm
bends or sags, but does not break, it
contains a good proportion of clay.
Swamp Clay:
Color: red to whitish to grey.
Depth: one to three feet below
the surface.
Moisture: very moist. Water can
be squeezed out by hand. During
the rainy season it is usually not
accessible due to high water table
and flooding. However, if buildings or wattle houses are being
constructed near the river or wet
area, this clay can be used to
spread on the walls.
Ant-hill Clay:
Color:
brown to reddish.
Depth: Depending on the size of
the ant-hill, clay can be up to
ten feet about the ground surface,
and down to ten feet below ground
level.
Moisture:
Figure 2
Clays irrSouthern Uganda:
Clays most common in Uganda are River
Bank Clay, Swamp Clay and Ant Hill
Clay.
Using ant-hill clay can serve several
purposes:
1. The clay extracted from the
ant-hill can be made into excellent
bricks and blocks, and also into roof
and floor tiles.
Color: red to whitish to grey.
2. The ant-hill from which the
clay is extracted can be dug further
and shaped into use for a kiln; i.e.,
the extracted clay can be moulded
into bricks and put back into the
three-sided opening and burned.
Depth: one to five feet below the
surface, i.e., below grade.
3. No transportation costs from
moulding site to kiln.
Moisture: semi-moist, easily
manipulated or squeezed by hand,
this is the most commonly used
clay in the region.
4. The ant-hill kiln, with three
well closed sides, will save fuel and
fuel costs, since it will hold the
heat longer and more efficiently than
conventional country kilns made of
loosely piled bricks.
River Bank Clay: (soft clay)
Location: it is usually found in
low-lying areas, and generally
accessible.
8
very dry.
Earth in many tropical and subtropical countries has properties,
which combined with hot sun and dry
air are favorable to making durable
mud bricks, blocks and mud walls.
Clay and sand are essential. Clay by
itself shrinks and cracks; clay mixed
with sand in proper proportions will
reduce shrinking and cracking. Too
much sand in the mixture weakens the
clay and makes it too soluble. Thus
no more sand should be added to the
clay than is absolutely necessary. If
the best bricks you can make without
cracking are too weak, one solution
is to add plenty of chopped grass,
straw or hemp to the mixture, and mix
very thoroughly.
Digging Clay for Brick-Making: Brick
clay should be dug early in the dry
season because it is much easier to
handle, due to the moisture content
of the soil, and requires the addition of less water to make mud.
The builder has a simple device for
determining and maintaining the proper proportions, mixtures and moisture content, and that is the device
of Cosma's Clay Pit, designed by Brother Cosma of the Kiteredde Construction Institute. It is a hole in the
ground with a technical purpose.
First, the builder clears away all
the shrubbery and extraneous material
from the plot of earth he intends to
use. He then digs a pit with two or
three vertical walls running across
its width or length. (See Figure 3).
As he digs, he cuts through two l-yers of soil, one of sand and another
of clay. He maintains one depth for
the length of the channel created by
the first vertical dividing wall, and
tests the clay produced at that level. He then digs a slightly deeper
channel across the clay pit to test
a different mixture, as shown in the
drawing. Eventually through this
procedure the builder will reach the
balanced mud mixture he is seeking.
When the testing proves that the proportions are correct, he should always dig his clay pit at the same
depth. It may take from three to
five different testing channels to
find the proper depth and mixture but
it is worth the time and effort if
the purpose is to make bricks of good
quality. In some cases, the blend of
sand and clay is so ideally balanced
that once the proper depth is known,
it can be dug and used indefinitely.
I. CLEAR PAPY RLJS.
2. DIG PIT. AFTER SEVERAL
HOURS OF PlbGIN6,
WATER
MAY SEEP IN. COtqTlNdETD
AND WA7ER
UNIXWATER
\5 SEEPlNb
IN FASTER-I-HAN
CAN
BE BAILED.
ABANPON
PLY.
3. DIG NEXT PIT, CONTINUE
PROcESS OF EXTRACTION.
EXTRACT
CLAY
Figure 3
9
Processing the clay: The builder
digs and mixes the mud about six to
ten days before he wants to start
making bricks or start building with
it. First, he prepares a mat of banana leaves upon which to build the
mud pile, because the leaves will
help to retain the necessary moisture
in the clay.
next step is to make a hole two feet
deep by six inches in diameter in the
top of the pile, and fill it with
water. Cover with a matting of grass
about 6 to 12 inches thick, and then
moisten the grass once in the morning
and once in the afternoon.
As the clay is dug out of the pit, it
is piled on the mat of leaves near
the pit. It should be mixed around
by one's feet to detect visible impurities, and these should be taken
out. (Figure 4B). The clay should be
piled in three to five foot stacks.
Once the
constant
liminary
piled in
and five
clay becomes sticky with a
consistency in these prestacks, it is ready to be
a mound about five feet high
feet across at the base. The
.-.
After two or three days, remove the
grass and mix the clay again with
feet and hoes. Rebuild the stack and
let it continue to cure for several
more days. After 6 to 10 days from
the first stacking it will be ready
for use. If the clay is too sandy,
additional sticky clay can be added.
It is very important to mix the clay
well each time it is used. No large
lumps or stones are permissible in
brick mud, although small stones of
not more than l/4" in diameter are
not objectionable and may be useful.
(See Figure 4A and 4B).
Figure 4A
Figure 4B
..\a
Brick sizes: It is good practice to
follow some tested method in brick
sizes. Bricks require a certain
depth in proportion to their length
so that they will not easily break in
two. The length of a brick should be
in harmony with building measurements
and the width of a brick should always be slightly less than half its
length. The builder should carefully
plan his brick sizes if he does not
follow standard sizes.
10
The brick sizes which have been found
most practical in eastern Africa are:
Unburned moulded bricks 9" x 4" x 3"
when fired, produce burned bricks
ready for construction:
8.5”
x 3.5”
x 2.5”.
Unburned moulded blocks 12.5" x 6.5"
x 5.5" when fired produce burned
block ready for construction:
12" x 6" x 5".
noulds: In constructing a mould for
shaping bricks or blocks, hard wood
should be used. The pieces of wood
must be straight, and either sanded
or planed smooth. This is to ensure
smoothness and perfect moulding on
all sides of the brick or block. Care
taken at this stage will help to produce an attractive, marketable product. (Figure 5).
Bricks with Special Shapes: It i6
possible without extra CO6t t0 improve masonry by the use of rounded
corners. One benefit of the round
corner is its durablity, in contrast
to conventional sharp corners which
are easily damaged, particularly if
made with mud plaster. (Refer to this
for openings and parapets).
A 6lOtted brick for use against all
door6 and window jamb6 is a virtual
necessity. The slot accommodate6 the
strip on the frame so that the frame
will not shake loose in the wall.
(Figure 6).
The general thickness of wood used
for making the mould is l/Z". Moulds
made from hardwood should produce up
to 75,000 bricks or blocks before replacement is necessary. If hardwood
is not available, a strip of light
metal (tin> can be run along the top
edges of a softwood mould to prevent
wear as the striker moves over the
edge to sheer off excess mud.
When manufacturing bricks, have as
many as four moulds on hand, if there
are that many skillful men available,
and enough labourers to keep them
busy and supplied with clay.
MOULD
MULTIPLE
MOULD
Figure 6A
FOR
RbUND
COrWFR
ti3ULL NOSE)
BRIcY
Figure 5A
Figure 5B
SIDE
VIEW
TOP
Figure 5C
CaC\NER
VIEW
FASTENED
Oic M-ETA2
To WOULD.
Figure 6B
11
SWT’
BLOCK
IN
SCsrWET
-PLACE
FULL
S-KIP
FASTEHED
JAMB
Figure 6C
Calculating Brick Quantities:
Calculate the total area of all the
walls in the building you are planning by measuring the total linear
feet (length) of each wall, and
multiply by the height. There are
six standard bricks to every face
square foot of wall. A simple set of
calculations will reveal the number
of bricks needed for the job.
The area of a gable is the width multiplied by one-half the height. The
total area of tW0 identical gable6 is
their width multiplied by their
height.
TOP
VIEW
SLOT
SUE
OF
BLOCK
Figure 6D
Table Method of Hand Houlding Bricks
and B1ock.s:
Table or slop moulding is the most
common moulding practice used in
Uganda today. There are generally
three worker6 involved: the moulder,
the layer, and the helper who assists
both. The procedure is as follows:
1) A simple table is made by using a
2” by 8” boar4 nailed to two 6” x 6”
wide poles, which are driven at least
two feet into the ground. The table
surface should be at the level of the
moulder's waist. (Figure 7).
2) The drying ground must be very
In estimating brick quantities, do
not deduct for openings, such as windows and doors, unless there is a
special reason for doing 60. Extra
bricks are always useful, and a surplus over and above actual need6
allows one to select the best bricks
and to discard those which are less
well moulded. As a general rule, if
one has sufficient time and money, it
is worth it to make a few thousand
extra bricks.
12
smooth for laying out the moulded
bricks, otherwise the bricks will be
badly shaped after drying.
3) The clay mixture should be slightly wet.
4) The moulder stand6 near the table.
At his right hand side is a small pit
for holding water, or a bucket of
water. At his left hand side is a
pile of prepared clay.
5) He takes a clean mould from the
water pit or the bucket, and places
it in front of him on the table.
6) He takes a piece of clay from the
clay pile and quickly forms it into a
rough shape equal in size to about
one and one-quarter of a brick, that
is, slightly larger than a brick.
7) The piece of wet clay is raised in
both hands and thrown with some force
squarely into the mould on the table.
(Figure 7).
are easily damaged or knocked out of
shape. Very wet bricks at this stage
of the moulding process produce poor
surfaces, and after firing, are generally not as strong as dryer bricks,
and usually sell for a lower price.
10) After sliding the brick out of
the mould, the brick should he covered by a handful of grass to
prevent the sun from drying it too
quickly, and to keep rain from changing its shape.
11) The moulder repeats the process.
8) The moulder take6 the striker or
straight stick, and holding it at an
angle, smooths off the top of the
brick. The excess clay from the top
is thrown back on the pile.
9) The brick in the mould box is
passed to his left side to be taken
away and layed out on the drying
ground. Caution: water is used as
the release agent to help slide the
brick from the mould. Very wet bricks
It is worthwhile to note that the
brick moulder and brick carrier are
two very important people in the
brickmaking process. The moulder can
tell if the quality of the clay i6
good or poor as he work6 with it, and
the carrier because he must make sure
that the bricks are properly carried
to the drying ground and carefully
laid out with no damage or loss of
Shape.
The same procedure6 are used for
block making. It is important to remember that blocks take several days
longer than bricks to dry out.
Figure 8
13
Drying and Stacking Bricks and Blocks
The drying ground must be very well
prepared so that it is smooth and
free from small holes, bumps, stones
and grass. It is preferable to cover
the drying ground with either sand or
sandy loam, which is then smoothed
off. It is a waste of effort and
time to locate, dig up and prepare
good quality clay, to make first
class bricks, and then spoil them by
laying them on badly prepared, rough
drying ground.
When bricks are carried from the
moulder's table to the drying ground
in the mould, the layer takes the
mould and turns it upside down on the
ground and iifts the mould from the
bricks. Sometimes a slight shaking
of the mould box is required, but
this must be done gently so the
bricks will not lose their shape.
Although the bricks are laid close
together, care must be taken to prevent damage caused by pushing newly
made bricks against or into those
already stacked on the drying ground.
As soon as the bricks have been laid
out, they should be covered with
grass, and the grass should be dampened with water. This prevents the
bricks from drying out too quickly
and keep6 them from cracking.
(Figure 9).
Within two days after being laid out,
the bricks can be turned on their
sides and covered again with grass.
After another several days, the
bricks should be turned again and
placed on end.
Figure 10
After one week to ten days, bricks
can be stacked up in an open setting,
or in a covered shed which is open on
the sides. If the bricks are stacked
in the open, thei?the lines of drying
bricks should run from north to south
so that the sun is able to cover both
sides of the stacks. When stacked in
the open, grass can be applied over
the top for protection, particularly
in the rainy season.
STEP=
Figure 11
Figure 9
14
In the more remote regions, it may be
quite impractical to import even
those materials with which to build a
permanent brick kiln. Anyone who intends to make fired clay bricks in a
remote location needs to know how to
construct a kiln in which to fire the
initial batch of bricks. Such a kiln
may also be the convenient and practical way to test the quality of the
clays from selected deposits in the
area for the manufacture of ceramic
products.
Reasons for Bricks Cracking:
1) Clay not mixed well with water.
2) Clay mixture not left long enough
in the clay pile to age.
3) Bricks stick to soil of uneven
drying ground.
4) Too much sand in the clay mixture.
5) Bricks are not covered soon enough
after being laid on drying ground.
6) Drying too quickly.
Large Country Kilns:
The Burning of Bricks jn a Country
Kiln.
Large country kilns have been used in
many parts of the world, and although
they are not as efficient as permanent kilns, millions of bricks have
been produced in them. Fuel consumption has been a problem, since many
country kilns are inefficient arid
waste precious wood. Properly designed, however, their efficiency can
be raised considerably, and their
fuel consumption can be maintained at
or near the levels reached in more
modern firing systems. The relative
lack of controls on burning, compared
with other production methods, as
well as the fumes emanating at ground
level, have often made these kilns
unpopular when located in or near
residential areas.
Due to specific economic conditions
in Uganda, and the universal economic
conditions in many developing countries, mechanized transport costs
rise rapidly with higher fuel costs,
and it becomes less practical for
building materials, such as bricks
and bags of cement, to be transported
for long distances.
The large brickworks located on the
outskirts of large towns, for example, find it less economical and
profitable to supply potential customers in the distant rural areas.
Rural builders must therefore seek
local suppliers of basic materials
who have been able to find and utilize suitable sources of raw materials that exist in the locality.
Opportunities will arise for the
village cooperative or local entrepreneur to carry out the small-scale
production and marketing of fired
clay bricks ax-Jtiles. The same is
true for the production of cementing
and mortaring materials, when suitable local deposits of clay, limestone, pozzolanas and other raw
materials are available.
'
Small Country Kilns:
Af this point in history, small kilns
are very useful in Uganda. A small
kiln is suitable for use by the small
contractor to fill his building needs
or by a farmer to supplement his income while his crops are growing. A
small kiln can be the first stage of
development of a small brick factory,
and in fact is a small factory.
The design and performance of a small
country kiln are interesting, due to
the well-insulated walls. Their design not only effects savings in fuel
15
-
consumption, but also promotes a uniformity of firing in the bricks, as
is evident when such a kiln is dismantled.
A small country kiln can have a capacity ranging from 2,000 to 10,000
bricks. For a kiln designed to produce 4,000 bricks, the external dimensions are 2 meters long by 1.5
meters wide, and a maximum height of
2 meters, equal to 20 layers of
bricks placed on edge. A single
firehole runs the length of the base
of the kiln, though it is open at one
end only. This firehole is approximately 500mm wide at its base by 400
mm high, or in other words, two brick
lengths wide by four brick widths
high at the middle.
The bricks of the first five layers
are laid with their stretchers across
the kiln (length-wise). Above this,
the bricks have alternating direction, that is, either laid parallel
to the length of the kiln, or across
it. Up to the twelfth layer, length
and width are constant. Above that,
the kiln tapers in a pyramid shape to
the twentieth or topmost layer.
Surrounding the kiln on all four
outer sides, up to the twelfth layer,
are other sun dried bricks. These
form a double cavity insulating wall.
The inner cavity is continuous, and
filled initially with coffee or rice
husks, sawdust and woodchips, or
other agricultural residue. These
are heaped on the other parts of the
kiln, as well, to provide additional
insulation. Eventually the residue
burns during the firing process, but
by that time it has served its purpose, and the resulting ash continues
to conserve the heat in the kiln.
Woodlogs are burned in the firehole.
The amount of fuelwood consumed is
approximately 60 to 75 meters for
every 20,000 bricks. To reduce the
cutting of standing timber, it should
16
be possible to add sawdust/woodchips,
coffee/rice husks or other agricultural residues, to supplement fuel
requirements and reduce the volume of
firewood which must be burned to
maintain adequate heat levels.
The fire is built up slowly while the
remaining moisture in the bricks is
being expelled, in what is known as
the "water smoking" period. After
this the tntensity of the fire is
increased. The addition of fuel
lasts for approximately two ts
four days, and then the firehole is
blocked off. The kiln is allowed to
burn itself out and to cool down.
During firing the sides of the kiln
feel only slightly warm, demonstrating the effectiveness of the insulation. Heat escapes only from the
top. Obviously, the bricks forming
the cavity walls are not properly
fired, but they can be used again for
the same purpose, or else placed inside the kiln to be fully fired the
next time the kiln is used.
Usually the kilns have the disadvantages of lack of control over the
firing. In windy conditions, the
burning may be too fierce and cause
partial melting or slagging of the
bricks. A remedy for this is plastering the exterior with mud to
prevent drafts, and this is fairly
common, but this means that the
"plastered" exterior bricks are
ruined and not worth refiring.
The country kiln is usually so well
insulated that once the operator has
learned, by experience, how much fuel
to use, the burning proceeds uniformly in any kind of weather conditions.
During the rainy season, a roof can
be added above the kiln. Simple pole
frame construction with palm or banana leaves, papyrus or thatch will
make an adequate roof.
Apart from items such as a simple
roof, little or no capital investment
is needed, which is a main advantage
of the country kiln, The process,
from moulding the bricks to unloading
finished bricks from the kiln, need
take no more than three weeks for a
4,000 to 10,000 brick kiln.
In constructing a kiln, begin with
well drained, dry ground. A fired
brick foundation can also be used as
a base for the kiln. A brick base is
effective as an insulator. It can be
leveled easily, and avoids mud and
excess dampness in wet weather.
For those responsible for small-scale
projects in remote areas, once a
source of mouldable clay of low
shrinkage has been located, the most
convenient means of completing an
evaluation of the local raw materials
may be simply to fire some brick in a
country kiln. It is an appropriate
means of getting production started
when the capital for construction of
a proper permanent kiln in lacking,
as it often is.
The overall length and size of the
kiln depends on the number of bricks
to be fired. The width of a country
kiln should never be greater than 15
to 20 feet, mainly because fuel consumption increases with the size of
the kiln, and size increases labor,
costs and construction time. In
Uganda, the width of an average kiln
of this kind is 8 to 12 feet, once
again depending on the number of
bricks to be fired.
Kiln Construction
A country kiln consists of three
parts:
Firing the kiln is the end-point of
the brick-making process, and is the
component which governs whether or
not the bricks will be durable and
strong. At the point when firing
begins, money, time and effort have
been expended to making bricks of
good quality, and therefore it is
very important to remember three main
points: (1) fire only good bricks,
not cracked or badly shaped bricks;
(2) use good quality fuels for burning; and (3) build an efficient kiln.
1) The legs, which form the lower
section around the fireholes;
2) The main setting or body, which
forms the bulk of the middle section
of the kiln, which is built by alternating rows of headers and stretchers
(bricks laid lengthwise and endwise
on alternating rows), with spaces between the rows of headers. (Fig 12C).
3) The outer cladding or shell, which
is made by bricks set close together
around the outside and the top of the
kiln, and sealed with mud. This forms
an insulating casing around the main
body of the kiln.
GROUND PLAN OF BRICK KILN
[email protected] BEINGPILED IN THE KILN.
LEAVE AT LFAST
‘/,”
5PACE
EACH
cViOUN
d
D
EmCK.
Figure 12A
Figure 12B
17
Figure 12c
brick lengths
width 1, in inches
1157 1 610
1
914
1 610
1 914
) 610
Construction of the kiln is started
by setting out the first 5 layers or
courses for the legs, beginning with
a stretcher, breaker, stretcher, and
breaker until the 5 courses are completed.
The next 3 courses are corbelled (see
figure) to form arches over the tops
of the fireways.
From the 9th course up to the last 2
courses, each row of stretchers and
headers has a l/2 inch space between
the bricks. Each alternate course
from the 9th row up is set at right
angles to each other, which has the
effect of making a checker-work of
bricks allowing heat to pass through
and keeping the bricks in good shape.
The last two courses are set closer
together to help hold the heat, but
in such a way that they are not too
air tight, keeping heat from flowing
properly upward.
A basic height for the kiln is 12 to
15 courses, but can be built higher
to accommodate a larger number of
bricks.
18
I&57 I
=+-Maxim
urn width
in millimetres
The outer casing or layer is built of
old bricks and mud, and can include
coffee and rice husks, or sawdust or
chips mixed with the clay and mud.
Kiln Operatfon
In a large country kiln, while burning 10,000 or more bricks, the dry
bricks are stacked on edge about 2"
apart in rows so that the fire and
heat can reach all the bricks and as
evenly as possible. According to the
number of bricks required, one or
more firing chambers are formed by
arching the dry bricks to make a
tunnel about 30" wide and from 15 to
20 feet long. The bricks in the kiln
should be spaced so that there is at
least l/2 inch of room between the
end and sides for circulation.
The firing of the kiln should be done
well in advance of the planned construction job. The bricks must all be
thoroughly dry before being inserted
into the kiln. The mud plaster which
is coated on the outside of the kiln
should be quite dry before the kiln
is fired. After firing, the kiln
will take some time to cool, even
after the plaster is removed.
Gather plenty of firewood to avoid
the possibility of running short of
fuel during the firing period. Care
should be taken to try to loccitethe
driest fuel. During the actual firing
period, one person will have to be on
duty all night. Four days may be
sufficient for the burning of 20,000
bricks, but a larger number of bricks
may take longer. The variables here
are (1) the number of bricks being
fired; (2) the efficiency of the kiln
and the fuel; and (3) the uniformity
and intensity of heat in the kiln. A
certain amount of trial and testing
is necessary to establish suitable
timing. The openings to the fire
chamber should remain fairly well
closed except when the fires are
being stoked.
To begin the firing process, fill the
firehoies or fireways with kindling
wood at the bottom, and add heavier
fuelwood as you build to the top of
the firehole.
The fireholes are lit at both sides
of the kiln, except in the case of
anthill kilns, which are only open on
the front side. As soon as the fire
is burning freely, the openings are
bricked up, leaving a small hole in
each fireway for air flow. (Larger
air holes are required in anthill
kilns to allow sufficient oxygen to
feed the fire evenly, and for circulation).
During the first 24 hours of the firing process, it is very important to
burn the fuel slowly. This is done by
using kindling, medium-sized wood and
wood pieces, plus coffee and rice
husks. The purpose of initial slow
burning is to cause the remaining
moisture in the bricks to evaporate
at an even rate rather than rapidly
to avoid cracking and damaging the
bricks.
After this stage, when steam and
vapor is no longer escaping from the
kiln, open the fireways and add major
firewood to the bed of coals, seal up
again with bricks (leaving air vents
open for necessary air flow), and
allow kiln to burn vigorously.
This process will take from 2 to 4
days, with fuel being added as needed
night and day. The objective is to
keep a strong fire and high temperature at all times, and to bring each
brick to a level where it is red hot
for an extended period of time. The
actual length of this intense burning
process depends on kiln size, type of
fuel and its degree of wetness or
dryness, weather conditions, and the
efficiency of the kiln.
After this intense firing process,
the fireholes are sealed up with
bricks and mud and the kiln is left
to cool down gradually for about 36
hours.
After the burning process, remove
plaster when it is cool enough to be
handled. When the bricks are cool
enough to be touched and handled, be
sure they are carefully sorted out.
The best burned bricks are used for
the outer faces of the main walls,
and the least well burned bricks are
for partition walls. If burned
bricks are made for exterior walls
only, the best ones are used for the
lower part of the wall, or that part
which is most exposed to water. Generally, the upper part of the exterior wall is protected by the overhang
of the roof.
Burned bricks are often more brittle
and fragile than unburned mud bricks.
Therefore they must be handled carefully. When the time comes to start
building the walls, burned bricks
should be drenched with water just
before being laid in the wall, partiularly when cement mortar is being
used, because a dry brick soaks up
the water in the mortar mix and
causes the mortar to harden and set
too quickly.
19
Kiln Fuels:
Wood (timber): Eucalyptus is very
commonly used in East Africa; wood
chips from a local sawmill are also
very useful. The size of the timber
should be 4" to 8" in diameter, and
the wood should be dried for 3 to 4
weeks before being used as a kiln
fuel. Dryer fuel wood will provide
hotter temperatures and more efficient burning.
Coffee husks: Can be used to start
the kiln fire. This is a good source
of fuel if you own the coffee husks
and do not have to pay for them, or
for the transportation of them. The
husks provide a fast heat, but not
for a great length of time, and thus
build up coals quickly.
Papyrus: Can be used in burning, as
in the case of coffee husks, if the
kiln is in a region where papyrus is
plentiful. Papyrus burns quickly,
and is not economical to transport.
However, it can be used satisfactorily to begin the firing process along
with wood chips and coffee husks.
Selection and Identification of Wood
and its Usage
The selection of timber and lumber
for construction depends l.argelyon
the character and quality grade of
materials carried in stock by local
dealers, or upon the materials which
the builder may be able to obtain by
his own means. Nevertheless, a basic
knowledge of the best kinds of wood
for special purposes will be very
useful, particu'_arlywhen important
work is being undertaken, and the
best results are desired.
Light framing material is usually
selected from woods that are plentiful and cheap, while heavy framing,
whenever possible, should be made
from timber which has both strength
and durability in the highest degree.
Since the exterior trim of buildings
is subjected to extremes of temperature, and to wind and rainstorms, a
durable material that is easy to work
with and is least influenced by these
changes should be selected. The
20
fibers should be firm and elastic,
without being brittle, sufficiently tough to avoid splitting when
being nailed into place, and to avoid
warping and cracking after being
erected.
Where wood is embedded in concrete or
masonry, or is buried wholly or partially in the ground, the primary consideration is durability.
For floors which will be subjected to
heavy work and traffic, the durability and wearing qualities are primary
considerations.
When interior finish is to be painted, any sound material that will hold
glue or wood finish, and stand up
well may be used, but where the wood
is to 'befinished in its natural color, by varnishing or waxing, its color, texture and quality of grain will
usually govern the selection.
Wood For Special.Purposes: The following list will.serve as a guide in
selecting and specifying the different kinds of wood for special requirements. These species are specific to Uganda, and are ranked in
order of preference based on durability. (Other countries or regions
can fill in each category with local
species).
framework, small trusses and
scaffolding: EUCALYPTUS, ENKAGO.
Light
Heavy framework, large trusses:
EMPERWERE, MLJSIZI.
Softwoods:
ENKAGO
MUSIZI
POD0
MUSENBNE
MUTUBA
plentiful
plentiful
plentiful
plentiful
plentiful, used for
bark cloth
Softwood Identification: In most of
the varieties, look for:
1)
2)
3)
4)
Needle shaped leaves
Evergreen
Trees bear pine cones for seeds
Smaller in diameter, 300-450mm.
Long timber, i.e., flagpoles, pole
beam for a .jighoist: EUCALYPTUS.
Exterior trim: MUSIZI, PODO.
Posts and sleepers in concrete or in
the ground: MAWASA, EUCALYPTUS.
Piles:
Hardwood Identification:
1)
2)
3)
4)
Broad leaves
Shed leaves once each year
Trees bear acorns, nuts
Larger in diameter, 750-1800mm.
ENZO, EUCALYPTUS.
As Processed Timber or Lumber:
Solid framed doors, sash and wainscoting: NKOBA, OMWASA, MUSIZI.
Parquet flooring: MUGAVU, NKOBA.
Interior trim: ENKAGO.
Furniture:
NKOBA.
Counter and table tops: NKOBA.
Tfmber Species Most Commonly Available and Used in Uganda: (Other
countries or regions can match local
species in the various categories).
Hardwoods:
MWASA EMPEWERE
EUCALYPTUS
MUGAVU
ENZO
NKOBA
OMWASA
plentiful
plentiful
plentiful
plentiful
plentiful
available
but not plentiful
plentiful
softwood:
1) Light in color
2) Light in weight
3) Easy to work with, plane,
shape, carve.
4) More elastic
5) Relatively cheaper to buy
6) Mainly used for carpentry work
and general joinery.
Hardwood:
1) Dark in color
2) Heavy in weight
3) Difficult to work, plane,
shape, carve.
4) Less elastic
5) More expensive to buy than
softwood
6) Used as m;ch as softwood in
many cases for joinery, due to
beautiful natural appearance.
21
Wood Treatment: to stop termites,
and woodrot caused by damp weather:
(local treatment of timber without
importing expensive materials).
Heat treatment for piles/poles:
Put the lower part of the log or
pole that is to be buried in the
ground into hot coals until the outer
bark is hard and turns a black color.
Continue to rotate the log until it
is finished on all sides. This process should only take 2 to *3 hours in
dry weather.
season, the wood will tend to draw in
additional moisture. During the dry
season there will be less moisture in
the wood.
Drying lumber (timber) is the removal
of water from the timber. Most builders know that it needs to be thoroughly dried before it can be transformed
into a useful product. The twin goals
of drying are:
1) Reducing moisture content (M.C.)
to a level consistent with the atmosphere within which the finished lumber will be used, and,
Used engine oil:
Bury a 200 liter drum 3/4 of the
way into the ground. Fill the drum
with used crankcase oil. Lower the
log or pole into the drum and let it
soak for several hours. If a drum is
not available, simply paint or rub
the used oil onto the log or pole
with a rag or a local paint brush.
Drying and Stacking Wood:
In many parts of the world, dry, well
cured lumber is seldom available,
particularly in rural areas. In parts
of Uganda, for example, one must travel over a wide area to procure sufficient standardized lumber of good
quality for construction. A builder
should plan well in advance, procure
sufficient lumber for his needs early
and dry it properly.
2) To avoid damage to the material
during the drying process, such as
cracking, warping and splitting.
The objective is to allow wood to do
its shrinking and drying before it is
used in construction or framing,
rather than after the woodworking or
manufacturing process.
In stacking and storing lumber, there
needs to be plenty of air circulation. The following drawings illustrate proper ways to stack lumber for
drying and for storage.
There are two characteristics of
moisture and evaporation in newly
processed timber, which the builder
should know:
1) Fibre Saturation Point: After
cutting and drying, the timber still
has 25% to 35% moisture in the cell
walls. This moisture tends to stay
with the lumber for many years.
Figure 13A
2) Equilibrium Moisture Content:
refers to moisture in the wood due to
atmospheric conditions. In the rainy
22
1" x 1" x 6' stringers are
placed between each layer of
'
boards to allow air circulation.'
Bottom layer is placed across
'~
evenly planed logs to protect
b
from ground moisture.
Figure 13B
‘.
..
“-.,/
A storage yard with several stacks
of boards, each of manageable height,
and separated for ease of access and
for adequate air drying and sunlight.
Characteristic shrinkage and distortion of flats, squares, and rounds as
affected by the direction of annual growth rings. The dimensional changes
shown are somewhat exaggerated. (From Air Drying of Lumber: A Guide to
Industry Practices, Agricultural Handbook No. 402).
23
CRAPTRR II
BASIC BUILDING COKPONENTS
Introduction
A house which is satisfactory on one
site may not be as practical, useful
or appropriate in another setting.
Therefore it is unwise to make final
decisions on building design until
the actual site has been secured, and
all its important features are known.
A builder should gather information
about the conditions on and around
the housing site in all seasons, with
respect to its suitability in these
categories, among others:
1) Health: Temperature, humidity,
altitude; the timing, value and
direction of winds; soil erosion;
swamp; rainfall; the prevalence of
disease; proximity to unsanitary
conditions over which the builder has
no control; depth of soil; the presence of large masses of rock which
radiate heat; the presence and value
of trees; whether the site is on a
hill, or in a plain or valley; its
proximity to other buildings, and the
character of those buildings; the
availability of safe drinking water,
and also health and medical care.
2) Work: Accessibility to and from
other people, centres of population
and appeal; proximity to place of
work, or to other work opportunities;
government favour.
4) Environment: This is particularly
important in areas where many houses
and buildings have been built already. The builder, when planning for
a site, should take into consideration the proximity of the site to
congested areas, and such factors as
noise, traffic, fumes, and general
cleanliness and sanitation; roads,
rivers, nearby institutions, schools,
and public transportation are also to
be considered.
Once these issues and the necessary
legal or title documents are worked
out with the appropriate authorities,
the builder can begin. The following
pages describe some of the basic elements of construction, making use of
locally available materials.
FOUNDATIONS
The choice of foundation type depends
upon the nature of the site, soil,
climate, style of the building, the
local construction codes, the available materials, the skills of the
builder. Some types of foundations:
Concrete Perimeter: (Figure 15).
Advantages:
1) Conforms to most local codes
2) No engineering required
3) Monolithic, solid, resists tremors
4) Crawl space protected from weather
and debris
5) Good in most soils
6) Good on level sites
CONCRETE
PERIMETER
(
WOOD
FLOOR)
3) Building conditions: Inquire
about supplies, labour, weather, the
building by-laws, restrictions, and
the plans for future developments in
the area. Occasionally a site or
area is found which is quite unsuitable for building a house or a compound, for one or several of these
reasons.
25
Disadvantages:
CONCRETE
SLAB
1) Careful framework essential
2) Considerable excavation needed
3) Requires volume of on-site concrete mixing
Concrete Piers: (Figure 16).
Advantages:
Figure 17
1) Minimal excavation and formwork
2) Good on sloping or steep sites
Disadvantages:
Wood Poles: (Figure 18).
1) Leaves underside of house open
2) Engineering often required for
codes.
Advantages:
CONCRETE
PIERS
1) Good on slopes and steep sites
where no cement is available
2) Does not require excavation or
disturbance of site
3) No cement forms needed
4) Practical in remote areas
Disadvantages:
Figure 16
Concrete Slab: (Figure 17).
1) Poles will rot eventually, but
can last up to 75 years with proper treatment
2) Not good in soft, wet soils
3) Deep holes may be difficult to
dig, depending on site, sub-soils
4) Leaves underside of house open.
WOOD
POLES
Advantages:
1) Same as concrete perimeter and
piers, plus,
2) Floor close to ground level
3) No floor or foundation rot
4) Water will not damage floor, easy
to wash
Disadvantages :
1) Not adaptable to steep site
2) Damp and cold if improperly built
3) Requires fill where high water
table exists
4) Requires considerable on-site manpower and skill to mix, pour and
finish.
26
Figure 18
The following section provides information about each of the four types
of foundations mentioned here.
LAYING OUT A FOUNDATION
The diagrams below illustrate some of
the important aspects of accurately
laying out a foundation.
Shown in the diagrams are batter
boards. These are set back about 4'
from the building lines to support
the strings which provide the accuracy in layout which is essential in
order to avoid problems later on. The
strings can be removed when working,
and building forms, and then
[email protected],
reset to check measurements.
Procedure:
Using a 3-4-5 (6-8-10) triangle to
get right angles, lay out a rough
outline of the building with corner
Drive three stakes about 4' back from
the corner stakes for batterboards, as
shown in the diagram. With a level,
water level, or line level, mark the
stakes all at the same level.
Nail boards (1 x 4s) onto the stakes
at the level marks, and brace all
boards to prevent movement.
Lay out exact measurements of the
building, using nylon string, if
available, or other string, with
loops stretched between nails on the
batter boards. Use 3-4-5 triangle to
get four strings in place, and then
check diagonals, adjusting the
TAUT
BAITER
,
BOARD
BUILDING
Figure 19A
STRING
LAYOUT
LINE
Figure 19B
IF BUILDING LAYOUT
IS SQU,4RE, , DIAGONAL
;I--;;5
WILL
LAYOUT OF BUILDING
LINES ;
STRING.5 MUs-r BE LEVEL
Figure 19C
STRIN 65
MARK
strings until measurements are accurate. On sloping building sites. the
batterboards will need bracing.
Water level: Use a length of garden
hose, with a short section of clear
plastic tubing taped onto each end
(it must not leak). Cap one end when
moving the hose. Ends must be open
when reading level. The water in the
hose will seek its own level and will
give accuracy readings to within
l/16" in 100 feet. (Figure 19D>.
No. of storeys
12
3
Thickness of foundation
wall in inches
6
8
10
Width of footing-inches
12
15
18
6
7
8
12
18
24
Thickness of footing
in inches
Depth of footing below
grade(surface)-inches
Inexperienced builders may find it
easier to first pour the footings,
then build forms for stem walls on
top of the footings, after the concrete has set. Experienced builders
usually pour footings and stem walls
at the same time.
ANCI-IOR
MlrD
Figure 19D
30 LT
SLLL
STEEL(REBAR)
-4
1F AVAIiABLE.
0AMBO0, BARBED
WLRE ANP OTHER TENSILE MATEFJALS
CAN BE USED WITH CAUTLON.
Figure 20A
A. Concrete Perimeter Foundation
H\llS\DE
S\TE
: POCYi-ING
The basic parts of a perimeter foundation are the footings, whi.chspread
the weight of the building uniformly
over the ground and the stem wall,
which supports the floors and walls
above the ground level.
Note: interior weight-bearing walls
which support the weight of the roof
must be supported by continuous footing with stem wall and mud sill, or
pre-cast piers, girder or beam.
Figure 20B
28
Excavating, Pouring, Forms:
.
I.
..’
1..
.’.
,.!I.
.
Jl.
LEFT: FOOTING
PUDDLE: S-I-EM
WITH
WALL
ON TOP OF FOOrlt4G
Using strings, mark lines on ground
for digging, with lime or powdered
chalk. Careful digging can save
concrete. Throw the dirt well back
from the building lines to leave
ample room for working. Be sure the
bottoms of the trenches are level by
checking with a carpenter level placed on a board or 2" x 4".
KEY
PCHjRED
RlGhT:
FOOTING AND STEP4
WALL POUR.ED SAPIE TIME
Figure 2OC
RElNFC+tCING
SHALLOW
STEEL :
STEPS, ,4S ABOVE
STEEPER
STEPS,
AS
;
Pouring: Reinforcing steel, if
available, or old fencing wire or
other metals should be in place about
3" above the bottom of the trench, at
least 2" from sides of wood forms.
Wet the earth in the trench before
pouring concrete so that the dry soil
will not draw moisture out of the
concrete.
BELOW.
After pouring, smooth off and level
the top of the footing (upon which
the form wall will rest). Put a two
by two on edge in the wet concrete
for a key to level. Be sure there is
vertical steel (hooks under horizontal steel) every 18 inches.
Figure 20D
FOOTINGS
MUST
UNDlSTURBED
Building forms:
DEAR
FlRM
ON
SOIL
FIRM SOIL: NO FORM BOARLX
RE UlRED.PoUR
CONCRETE
DIR 9 CTLY IN TRENCH.
tO05E
SOlL
: FORM
BOARDS
The forms for the stem wall are built
on top of the footing, which has a
key and vertical steel, to tie footing and wall together. Forms are
filled with concrete to the top. Thus
forms must be accurate in height as
well as horizontal measurements. The
2" boards commonly used for form lumber, are later stripped away from the
forms and used as joists.
Steel form ties are commonly used to
hold forms together while forms are
under pressure from concrete. They
remain under the concrete after it
sets. The ends are broken off after
forms are stripped away. Wire or
wood batts can also be used to hold
the forms in place.
REWIRED.
A 2 x 2 IS PRFSSI~D
INTO THE Wf3- CoNCRETE
TO FORM KEY.
Figure 20E
29
Procedure:
FORMS WtiERE
F00TING /#II
STEM WALLS TO
BE POURED AT SAME TIME.
(FOR BUILDERS WI-W SOWE FORMWIL-iJIf'lG
EXPERII~NCE.)
BUILDING
1) Using strings, build outside forms
first. Use builder's level or
water level to make sure the forms
are level all around. Use blocks or
stones to raise forms if necessary.
2) Check diagonals; adjust if necessary; accuracy is important here.
3) Insert steel ties, wire or wood
batts.
4) Bend horizontal steel and lay in
place before adding inside to form.
5) Build jnside forms.
6) Raise and tie steel as forms are
built.
7) Suspend anchor bolts in place.
Figure 21B
Reinforcing Steel: Depending on wall
height, two or more l/2" bars of reinforcing steel (rebars) are hung
inside forms with the wire from the
steel ties. (Figure 21A and 21B).
BUILDING
ALREADY
FOFWS ON TOP OF
POURED FOOTING
Pouring Concrete:
Formula when mixing it yourself: 3
parts gravel; 2 parts sand (sea sand
is best); 1 part cement. The less
water, the stronger the concrete.
Keep it stiff.
Procedure:
1) Have 3 or 4 helpers with as many
shovels. Rubber boots and wood
floats are needed, and a large wheelbarrow is very useful.
2) Spray or sprinkle the ground and
forms with water just before concrete
is poured.
3) Pour In layers. Pour bottom of
the form all the way around first.
This gives it time to set up, and
minimizes pressure and leaks.
Figure 21A
30
4) If concrete starts oozing from the
forms, it can often be stopped by
shoveling dirt against the side of
the form that is leaking, and pouring
at some other point along the form
for a while.
5) Tamp or puddle concrete in forms
with a 1 by 4 to ensure good fill and
to eliminate spaces.
6) Tap side of forms with a hammer
for smooth surface.
7) When form is full, trowel off the
top smoothly. The mud sill will rest
here. Check anchor bolts for right
height and vertical angle.
S> Clean off all tools immediately.
9) Strip form after 24 hours. Keep
concrete covered and damp for three
to five aays.
B. Concrete Slab Floors
If well built, a concrete slab floor
need not be damp and cold. Concrete
has a high heat storage capacity and
can be built to avoid dampness.
Procedure:
1) First build a standard footing and
stem wall up to a desired height.
Omit all vent and crawl space openings, but allow for sewer, water and
electrical lines, which must be installed in the floor and/or foundation wall before concrete is poured.
2) Remove all organic material from
the floor area.
Openings in Concrete: An opening in
a concrete wall must be blocked out
in the formwork before the pour.
These are usually rectangular openings with stringers left in. Vents
and apertures can have many uses, and
use determines the size needed: crawl
space to allow one to get under the
building; vent opening for good ventilation to help minimize termite and
dry rot damage; vents for plumbing
and wire openings.
GIRDER
SUPPORTS
3j Put down 4 to 6 inches of one and
one-half inch gravel.
4) Roll out 6" by 6" welded wire
mesh, or place 3/8" rebar 18" on center each way, if available.
5) Install any plumbing, wiring or
pipes where they should be in the
concrete.
6) Set anchor bolts.
7) Set wood screeds either temporarily or permanently.
Note: Interior bearing walls on slab
floor must be supported by footing
the same size as exterior footings.
LEFT: POCkET
FORMED BY
BLOCKING
OUT INSIDE
FORM.
R\GHT: ANCHOR BOLTS #OLD
TREATED
WOOD SUPPORT.
REED
Figure 22A
TEMPORARY
SCREED
IS !3AKED
ABOVE
SLAB
LEVEL
FOR EASY REMOVAL
AFTER
POUR.
MAXI MUM
EFFECTIVE
LENGTH
FOR STRAIGHTEDGE
IS IO- I2 FEET;
USE TEMPORARY
SCREED
A5
ABOVE
WHEN
POUR 15 WIDER.
Figure 22B
Figure 23A
31
REINFORCING
STEEL,
HAVE
PND
04fXBED
USED BAtiBC0
WIRE.
Figure 23C
STRAiGHTEDGE
\5 WORKED
BACK AND FoRr7-1 TO BRING
CONCRETE
TO ROWH FINlSH
LEVEL. AFTER 7\llS,
USE
WOOuEN
FLOAT, THEN
STEEL
TROWEL TO FINIS/-~.
MESH
UP DURING
POUR (IF A’/AILABLE).
PULL
SLAB
Figure 23B
The Concrete Pour (Brief
Instructiolls):
1) Pour 3 and l/2" finished floor.
2) Rake off level with a 2 x 8 resting on screeds.
3) Smooth off with large wood float.
A film of water will rise to the surface. When this evaporates, the slab
is ready for the steel trowel.
4) Continue trowelling until surface
is smooth and hard.
5) In hot weather, shade your newly
poured concrete if possible.
C. Cast in Place Concrete Piers
The main advantages of piers are the
mimimal formwork necessary, and their
suitability to sloping sites. There
are three ways to utilize them:
1) With regular footing, if height of
the concrete pier is less than three
times the diameter of pier, and if
piers are spaced six feet apart.
32
Figure 23D
2) With a grade beam, that is a
steel-reinforced concrete beam at
ground level that acts as a bridge to
tie all the piers together.
3) With deep holes and no connecting
footing or grade beam. In this case,
the weight of the building is partially supported by friction of the
soil around the piers. Holes are
usually six feet to twelve feet deep
depending upon soil conditions and
the height of the pier above ground.
It may be advisable to get some help
from an engineer in this case.
The following is a simplified system
for using concrete pier foundations:
1) Check with local builders regarding footings, footing sizes and depth
needed.
2) Dig footing trenches.
3) Enlarge footing trench around each
concrete pier. If the site is flat,
forms are probably not needed. If
the site is steep or sloping, stepping may be required. (Figure ZOB).
4) Lay 2 pieces of steel in trench,
supported about 3” above ground.
7) The next day, place forms over
pier locations. Plumb them at the
desired height, and brace with 1 x 4s
if necessary.
8) Insert vertical steel with 2" at
top for the insertion of anchor
straps for posts or girders.
5) Wire 4 pieces of vertical steel in
each pier area. (Figure 24B).
9) Throw some dirt around the base.
6) Pour trenches.
10) Fill with concrete. Be sure to
puddle with sticks to eliminate
spaces.
CAST-
IN-PLACE CONCRETE
PIE R
TYPICAL
CAST-IN- PLACE
COLUMN
FOUNDATrOt4
‘A”
24”
REBAR
0.c.
TIES
AT
ti0~l2Ot4I~~
Figure 24A
Figure 24B
Wood pole foundations are especially
suited to sloping sites where concrete work is difficult, or in inaccessible sites. Also, in terms of
affordable, low-cost construction,
pole foundations may be the most
practical solution for many builders.
The number, size of poles, depth below ground and spacing are determined
by soil conditions, and of course,
the size of the building.
D. Wood Poles
In some areas, properly treated poles
are said to last from 50 to 75 years
without rotting.
The same procedures described for
other foundations , particularly for
measuring angles and leveling, are
appropriate here.
A typical pole foundation treatment
33
would have a 6 foot hole with an 8”
concrete footing at its base to support the pole. After the pole is installed, the rest of the hole is
filled with tamped sand. (Figure 25A
and Figure 25B).
WOOD
POLE
TYPICAL
POLE
4” OR 6’
Cl RDERS
LET 1N l-0
POLE
MIN. 3”
FOUNDATION
12"DIAM.
F
6’0”
TREATED
DEEP
7 24"
PIAt-
HOLE.
8” CONCRETE &
FOOTING
Figure 25A
s!:::
POLE
FILL
TAMPw
Figure 25B
TYPES OF WALLS
Mud or Adobe Brick
Ecomomy demands that one make the
best use of materials, local or imported. It may not always be wise to
build with the cheapest materials available, if the objective is soundness and durability. It is worth devoting time to inspecting a variety
of buildings and the materials used
in them to see which ones withstand
the test of time. It is possible
that by gathering such information,
one will be able to discover materials in the locale which will provide
durability at reasonable expense.
Mud or adobe has been found to be one
of the most practical types of wall
construction, where the clay is suitable I and where there is enough dry,
hot weather to bake the brick.
A few suggestions are offered here
in this section about different types
of walls. An examination of various
types may be useful in determining
the kind of wall best suited for the
building being planned.
34
Mud bricks are adaptable to almost
all building requirements, except
where conditions bring about constant
washing or splashing of water. Mud
bricks lend themselves to corners,
jambs , arches a,ldother awkward wall
work, as well as straight wall work.
On a proper foundation, mud bricks
may be classed as sound and permanent
construction.
The greatest drawbacks are their inability, more in some locations than
in others, to withstand rain, and
their complete vulnerability to the
ravages of the termite or white ant.
The first problem has been overcome
in some areas by waterproofing the
mud plaster with cotton seed tar,
which, when dried, will hold cement
wash, which in turn is a satisfactory
base for lime washes.
In some instances, a weak cement
plaster has held to the mud brick as
a protective coating, but this seems
to be the exception rather than the
rule. The different rates of expansion and contraction of mud brick and
cement plaster causes the latter to
peel away from the face of the brick.
Brick sizes are provided in the
chapter 3n brickmaking. (Chapter I).
Mud Block
Many builders prefer mud block to mud
bricks. They lay faster and on a
good foundation may be regarded as
permanent construction. They require
special bonding at the corners to
give strength, and they are definitely not as satisfactory as mud bricks
in respect to odd measurements, awkward corners and special features.
Burned Bricks
These have been used where cement
plaster was considered a requisite,
or where the mud was considered to be
of such poor quality that mud bricks
were not satisfactory, or where good
clays are abundant. Considerable time
and skill are needed to produce good
fired bricks, they take longer to
make than mud bricks, and often have
to be transported for some distance
from the clay source and kiln to the
building site. In main house walls,
their size involves a three brick
wall, which is thicker than the standard mud brick wall, and such walls
are obviously more expensive. Burned
bricks are not always completely
waterproof. It seems likely that
clay lacks the properties necessary
to be an absolutely impervious material.
Concrete Block
It is hardly necessary to list the
advantages of this type of construction. Concrete block is indestructible as far as water and rain are
concerned. It is ant proof, clean
and strong, and is always acceptable
to the authorities and to building
codes. It is, or ought to be, very
attractive and esthetically pleasing.
Another great virtue of concrete
block is that it can be used for construction anywhere at any time. But
it has the significant drawback of
high cost. Particularly in regl9ns
and locales remote from railways,
roads and centers of production, the
cost of the cement alone is invariably prohibitive.
Block-making machines are available,
but they are not without their drawbacks. Very few workers care to make
a block mould. They are very heavy,
and the process requires scores of
metal pallets, further adding to the
expense of the operation. The lay up
is also expensive, if the work is to
be done neatly.
Despite these disadvantages, some
builders have ?earned by hard experience that the desire to save money
by using other materials has resulted
in so much continual patching of
walls made from other materials, and
related problems, that a concrete
block building might have been more
economical and better from many perspectives. This does not apply to all
buildings, of course, but particularly schools and public buildings,
which should be soundly and attractively built at the outset. In such
cases, the initial cost of concrete
block might represent a savings over
a long period of time.
35
Stone Walls
Veneer Walls
In many places, stone is the most
practical material for footings and
foundation walls. At the same time,
it has not always been recognized as
a very expensive material for walls.
It does not lend itself to fine
measures, jambs and special features.
It is costly to lay up properly, and
must be pointed up with cement, which
is another costly item.
The same principle mentioned in relation to corrugated iron wails, that
of backing the iron with mud, applies
to burned brick and to concrete block
walls. It is possible and permissible to build a thin outer course of
waterproof brick or concrete block
with a thicker backing of mud brick
or mud block. This is a veneer wall
and is strongly recommended as a
solution to many problems. It is
important to mention that one of the
essentials to good construction of
this kind is to provide frequent and
adequate ties between the veneer and
the backing, either by iron, or by
the more satisfactory method of headers or cross blocks and bricks.
If cement plaster is used on the inside, there is the added expense of
filling in large cavities with costly
cement. Stone walls must be thicker
than mud brick walls to provide the
necessary stability.
On the other hand, a well built stone
wall is permanent, attractive and
substantial. It may be a necessity
where mud is unsatisfactory, where
good clays are not available, and
where stone is relatively inexpensive
and plentiful.
Corrugated Iron
This type of wall is not commonly
used for dwellings, but for certain
other types of structures it is often
the most practical. It has some
unique properties. It can be built
in a day or two. It is waterproof,
and when fastened into place, never
requires attention or repairs. It
is durable and can be used at a
later time for a different purpose.
It can serve as a dwelling house wall
very acceptably for a year or two if
it is backed up by mud, which in turn
is plastered. As in the case of concrete blocks, this type of wall can
be put up anywhere at any time. If
skilled labour is not available, one
can do it alone, since installation
does not require heavy work.
36
Pise or Ramned Earth
In this method, slightly damp soil is
used as a removable form or mould.
When the form is full, it is taken
down and set up to be filled again.
The chief factors in determining
whether this type of building construction should be adopted are:
builder's preference; climatic conditions; the presence of the right
soil; shrinkage; the scarcity or complete lack of bricklayers; the ability to make and properly handle the
mould; cleanliness and reduced
handling (as contrasted with bricks).
COIQOU Mud Walls
This type of wall is remarkably durable in some locations. Although it
is not recommended for the walls of
permenent dwellings, it should not be
ignored as a possible material for
the walls of other kinds of structures. It makes a practical wall if
built upon a solid foundation, such
as stone, and if it is adequately
waterproofed. The greatest difficulty would seem to be that of
persuading the builder to keep the
walls plumb and straight. If houses
and buildings must be constructed of
mud, they could be made more permanent and durable by putting in stone
footings, foundation walls, and ant
proof coursing. None of these features requires great expense, and
would save repairs and rebuilding in
the long run.
In all of these designs, it must be
understood that a base of firm, undisturbed earth is essential, and
that thorough waterproofing inside
and outside, with adequate stiffening
or bracing at every storey height are
absolutely essential contributors to
the stability of every masonry wall.
The drawings themselves may not make
it sufficiently clear that mass is an
essential constituent of masonry durability. In some of these examples,
if not all of them, the thickness of
the wall may be quite inadequate due
to the presence of unusual stress
factors such as weight or vibration.
Masonry walls, including partitions,
must be massive enough to withstand
external forces, and to resist cracking due to above-ground conditions.
(Figure 26A).
Thickness and Height of Walls and
Gables
Thickness and height must be considered in selecting the type of wall
for a building. Gables, two storey
buildings, and high walls require
very special care in design. The
following is recommended as a safe
procedure in most cases.
-
/5’-18”
EXTERIOR
16”
-
‘Ii3
WALLS
Figure 26A
37
Three types of base for gable walls
Note that in the figures on the left and in the center,
the
concrete course provides a solid base for the gable, even
though there might be a plaster failure through which water
might find a way. In the figure on the right there is no
vulnerable spot.
Figure 26B
Thicknesses of gables and their
supporting walls.
Neither scaffold nor any other
kind of stress should be borne
by high gable walls. Unless
there are a pair of butt-resses,
there should be a rigid stay to
the top of the main wall, and a
stay for every ten feet above it.
These stays should not be removed until all heavy work, including roofing, is completed and
the frame which is to hold the
roof permanently is in its final
place. Movement in a green, unsupported masonry wall is dangerous . In a house wall there are
usually cross walls to stiffen
the end wall supporting the gable.
Leave the masons' scaffold in
place until the roof frame has
been secured to the gable wall.
Figure 26C
38
II’
Bricklaying: Solid Walls and Joints
in Brickwork.
Importance of Mortar:
In laying bricks, it is customary to
bed the bricks in mortar. The mortar
serves several purposes, two of which
are it has the effect of making the
wall waterproof and air-proof under
ordinary conditions. Of course, an
ordinary brick wall. is never absolutely impervious to water or air,
but mortar joints prevent rain or
wind from entering a house in such
large quantities as would be the case
with walls laid up without mortar, or
dry, as it is called.
Another advantage in using mortar in
the joints of brickwork is that a
wall thus becomes one solid mass,
which increases its strength and stability. An important consideration
often overlooked is that mortar gives
a certain amount of elasticity to the
wall. Lime mortar is more elastic
than brick, and by having a light bed
of mortar between each brick course
or layer, many bricks are protected
from cracking due to settling or
other causes. (See Figure 27A).
that the strength of brickwork cannot
be dependent on the strength of the
bricks alone. Other factors influence strength, such as the quality of
the mortar and the method of laying
up and bonding the bricks. Therefore, the value of a good brick, as
far as strength is concerned, may be
decreased by the use of inferior mortar, or by being laid by a bricklayer
who does not understand his trade.
Size of Mortar Joints:
When building a wall, sufficient mortar should be used to fill all the
spaces. Lime mortar, which is the
kind often used in the construction
of houses, is not as strong as the
brick, and it is recommended that a
bit more mortar than that simply
needed to fill the spaces should be
used.
Figure 27B
V
LEVEL I INE
Figure 27A
Meaning of Brickwork:
The term "brickwork" refers not only
to the bricks themselves, and working
with them, but also to the mortar in
the joints. It can be readily seen
Another consideration is appearance.
Thick joints in brickwork present an
unsightly appearance. Tn proper brick
laying, a layer of mortar is first
spread over the preceding course.
Then each brick is laid in place on
the bed of mortar, and tapped with a
bricklayer's trowel until sufficient
mortar is squeezed out to make a
joint of the required thickness. TO
force a brick down until it touches
the brick beneath is not good practice, because it forms thin joints
39
without sufficient strength. If a
special brick is made with a “frog”
on one side, an indentation or rise
for special fittings, it is laid with
the frog side facing up.
The more regular the surface of the
bricks, the closer they can be laid
together, and the smaller will be the
joints. With ordinary brickwork, the
joints should average not more than
l/4” in thickness. In working with
machine manufactured bricks (pressed
bricks), the joints can be made
smaller, probably l/8” to 3/16” being
the usual thickness, because the
bricks are smoother and have no irregular projections.
basic materials (brick and mortar),
the bonding of a wall constitutes
most of its strength.
Types of Bond in Bricktmrk
FLEMiSH GARDEN WALL BOND
FLEMtSH 8OND
Bond in Brick
Lime mortar is not as strong as
brick, at least for some time after
it has set. It can easily be seen
that
if each brick in a wall were
placed directly on another brick, any
great weight imposed might cause the
vertical mortar joints, which would
all be in a row, to split open. There
is something more to be considered in
laying up a brick wall than simply
placing each brick upon a bed of mortar. A brick wall, ii it is built
correctly, must be tied together in a
way that utilizes all the potential
strength of the bricks and the
mortar,
In bricklaying, all corners and
joints should be carefully plumbed;
the courses (layers) of brickwork
should be kept perfectly horizontal,
which requires uniform application of
mortar; and all aspects of building a
good wall must be complied with. The
merit or quality of the brickwork
must be judged by the thoroughness of
the bond observed in every portion of
the wall, both lengthwise and crosswise. The bond must be maintained by
having every course perfectly horizontal, both longitudinally and
transversely ,~as well as perfectly
plumb vertically. Aside from the
qualities and characteristics of the
DUTCH
I
II
BOND
II
ENGLISH 00ND
Figure 28
40
II
I
Terms Used in Bonding
Bonding brickwork means the process
of laying bricks across one another
so that one brick rests on parts of
two or three other bricks below it.
This amounts to the same thing as
breaking the joints. When built in
this manner, it is difficult for a
wall to fall without actually breaking the bricks.
When the bricks are placed lengthwise
on the face of a wall, they are termed stretchers. When they are placed
crosswise, and only their ends are
exposed to view in the face of a wall
they are called headers.
A course refers to the thickness of a
brick and a mortar joint.
Figure 29
Roof Framing
Choice of shape of a roof depends on
weather conditions, overall size of
the building, the materials available
and the skills of the builder. The
following figures illustrate three
basic types of roof: gable, shed 3
and flat roof.
GABLE
SHORTER
SPA&
TFAN
FLAT Ok SHED; CAN
HC\VE
LOFT
ori
2!4!,
.ED
SIMPLE, CAN HAVE
M LOFT ONE SIDE.
.fiTOr;y.
Figure 30A
Figure 30B
4T
SIMPLE. LOW PROSE,
f4/JA&D ZND STOdY
- .
Figure 30C
Instructions for Building A Gable
Roof
It is assumed that in most rural
areas, builders will have a framing
square, but squares and other tools
may not be available everywhere, due
to high prices and the state of the
hardware and tool-making industry.
By all means, if a square is available, it should be used.
The following instructions are for
framing without the use of a framing
square. (See Figures 31A, 31B, 31C).
4) Make ridgeboard and birdmouth cuts
on rafter. Hold pieces in place to
check fit.
5) Using this piece as a pattern,
mark and cut a second rafter.
6) Check all along length of ridgeboard with these two sample rafters
opposite each other.
11 Support ridge board temporarily.
7) If the fits are satisfactory, use
one as a pattern and cut the other
rafters.
2) The measurements on both sides
from the ridge board to the plates
should be equal.
8; Mark rafter location along both
sides of the ridge board, and both
plates.
3) Tack the rafter in place and mark
“plumb cut” at ridge board and “birds
mouth” at plate.
9) Install rafters.
42
10) Attach ceiling joists at 2’-0” on
center, or cross ties at 4’-0” on
center, and collar ties at 4’ on center. This braces the roof frame and
gives it strength.
11) Rafters should be placed at 24”
spacing to provide for the maximum
strength for purlins and roof
covering.
Figure 31A
NOTE: FIREBLOCKING
EVERY
E:LGHT FEET.
Figure 31B
REQUrRED
I
Rafters at 24” spacing can be
sheathed with l/4” lumber.
Sheathing over open cornices
should be boards, or can be
plywood over roof. In this
way, no ply exposed to weather
or visible from underneath.
Sheathing
Figure 31C
Eaves
A builder may wish to consider three
types of eaves: open cornice, closed
cornice, or boxed cornice.
1) Open cornice: Rafter overhang is
exposed , and blocking is vented and
screened. If a gutter is desired, cut
rafter end plumb.
OPEN
2) Closed cornice: No rafter overhang
and cheap and fast to build. Good
for heavy winds but has the disadvantage of no rain protection for walls
and no overhang protection for vent
holes.
3) Boxed cornice: Rafter tails are
boxed with screen vent in soffit. The
vents should not be directly over
doors, or within 3’ of windows or
doors.
CORNICE
CLOSED
CORNI
BOXEP
CORNICE
Figure 32A
Figure 32B
Figure 32C
Flat Roof
An advantage of the flat roof is the
possibility of adding a second story
later on, if the weight-bearing walls
are built with sufficient strength.
Use floor joist-sized rafters, and
cover with whatever good roofing
material is available. If no second
story is planned, it is a good idea
to give the roof a slight angle or
pitch. This can be done easily by
adding an extra plate to the wall on
one side, which gives the roof about
a one and one-half inch slope.
GRAVEL
FLAT
ROOF
EAVE
f
/
/
\
TAR
30
OVERHANG
FRAMING
STOP
4. GRAVEL
LB. TAR PAPER
Figure 33B
Figure 33A
44
Roof Trusses
Trusses are designed to span greater
distances using smaller wood or steel
sections, through the use of geometric configurations (triangulation).
Trusses are built on the floor or on
level ground outside, and then raised
into place by two or more people. The
LIGHTWEIGHT
APPKOXIMATE
outside walls are constructed first
to support the roof, and then the
trusses are set in place. The roof
is then covered or sheathed. Trusses
must be built accurately for a good
fit, and must be strongly supported
by cross-members which are properly
placed and tied in well.
TKUSSES
NUMBERED IN
ORDER
OF STRENGTli.
Figure 34
45
Roofing Materials
Manufactured roofing materials such
as rolled roofing, asphalt shingles,
and wood shingles are generally very
costly or unavailable in rural areas.
The most common materials are likely
to be tiles of clay, ceramic or concrete, corrugated iron sheets, grass
thatch, or papyrus or other reeds,
Corrugated iron: In the construction
of buildings or sheds, corrugated
sheets or roll plate are frequently
used. Usually these materials are
made of galvanized iron or aluminum.
It is good practice to buy the sheets
in widths 2’ to 6’, and their length
may vary from 6 to 10 feet.
When corrugated sheets are laid for
roofing, the edges are overlapped.
This overlapping, known as side-lap,
is usually at least one and one-half
corrugations or grooves, or approximately 4”. The top sheet is laid
with the side edge turning downward
towards the ground.
46
Figure 35
In addition to side-lap, the ends
must overlap as well. A flat roof
requires a greater degree of end-lap.
It is also important to know that the
point where two pieces of metal overlap will require additional roof
framing and support. A good rule to
follow is:
12” rise per foot, use 6” end lap
6” rise per foot, use 9” end lap
1” rise per foot, use 12” end lap
Calculating number of sheets:
The following is the procedure for
calculating a pitched roof with a 6
inch rise per foot, &th a total surface area of 20’ by 40’. This problem is for calculating for sheeting
in terms of vertical distance.
2 ten foot sheets will not cover
from ridge to eave and allow 6”
for end lap.
3 sections with two end,laps are
required (20’+ 6” + 6” = 21’).
Calculating sheets for horizontal
distance_:
Judge which combination of sheets
will provide 21 feet of vertical
distance. A good combination
would be 9’ + 6’ + 6’.
Allow 4” for side-lap, which means
that each 2’ by 6” row actually
covers 2’ and 2” of roof area.
Each vertical row would require
one 9’ length of sheeting, and
two 6’ lengths.
Papyrus,Reed
Thatch Grass
Mature reeds must be selected which
are at least 8’ in length and l/2” in
thickness. The reeds should be
dried for several weeks, on racks off
the ground if at all possible, and
turned several times during the process to insure thorough drying. The
length of the drying time depends on
weather and dampness. When ready for
installation, bundles of reeds should
be tied into 8” to 10” pieces and securely attached to roof purlins. The
life span of papyrus roofing can be
up to 20 years if properly cared for.
Clean tall grass at least 3 feet in
length should be used for the typical
shed or roof covering. The thickness
of each bundle can be measured by the
handful. After cutting, the grass
requires 1 to 2 weeks of drying time,
depending on the season. Before installing the bundles and setting them
into place on the roof, soak them in
water, and lay with the butt ends
from ,the eaves up. The water treatment helps to pack the bundles in
laying them onto the roof structure.
The bundles should be tied to the
purlins downward and then upward,
always rotating each line. The lifespan is up to 8 years if properly
cared for and patched several times
per year.
Figure 36
Building frames and sills for windows
Windows and Doors
1) Use clear, dry wood
Wood windows:
2)
Advantages:
1) good looks
2) small panes, cheap to replace
if broken
3) are often available used (from
other buildings) and at a good
price,
3)
4)
5)
Disadvantages :
6)
1) must be maintained with putty
and paint
2) require time to install, build
3) more likely to leak than prefabricated windows, sashes.
7)
8)
9)
Make inside of frame at least
3/16” larger than the actual
dimensions of the sash, to provide clearance to install sash,
and room to open window if it
is to have hinges.
Use 2 x 8 clear stock for sills
Use 1 x 6 jambs
Cut out parts and assemble with
nails and glue. (Use waterproof
glue If available).
Completely assemble frame before installing.
Place frame In opening, shim
tight with shingles or wedges.
Check diagonals and nail
through jamb into studs.
Add stops, stool, apron, trim
last.
Exterior Trim:
HORIZONTAL
CR055 SECTION
The following figures illustrate
some of the principal issues in the
design and construction of trim for
window assemblies. The most lmportant point is that the installation
must be made correctly, and properly
sealed to avoid leaks. (Figure 37).
VERTLCAL
CROSS SECTION
OF WINDOW
ASSEMBLY
Figure 37A
HOR\ZONT/4L
CROSS SECTION
TRIMMER
/
WHEN USING
NAIL FRAME
l-HEN
SHIM.
I” FRAME,
TO TRIMMER,
Figure 37B
48
SHIM
Figure 37C
TYPKAL WINDOW
FR4ME
ASSEMBLY
CASEMENT
VEN
FOR CASEMENT
WINDCIWS
HINGE MOUNTS
ON HEAD AhD
SILL,
SASH OPENS AWAY
FROM
HINGE
JAMB.
AWNIN 6
Figure 37D
Figure 37F
Figure 37E
Doors
Weatherproof homemade wooden doors
must be made so that they will not
sag or warp. They mus t be properly
designed and built of good ma:erials.
(See Figures).
EXTERIOR
INTERlOf?
DOOR
DOOR
&VERTICAL
2x6
TZ G BaARDs
/
ROU7-E GROOVE
IN ENDS
OF VERTICAL
BOARDS FOR
TONGUE OF
RAILS
I” BOARDS
(USE DRY WOOD 1
2x4 ‘Z’
BRACE,
GLUE AND NA\L
I-tORIZONTAL
TOP d BOTTOM
I” BLOCK FOR
POOR IATCH
HINGE AT
tlORIZONTAL
BRACE
I-iOMEMAIJE
v
)
Figure 38A
DOORS
Fi.gure 38B
Jambs
7) Screw hinges to door.
Two of the more common types of jambs
are:
8) Lay jamb next to door and mark
jamb for correct placement of
hinges. Allow l/8" clearance between
top of door and head jamb.
1) rabbeted: good for heavy doors,
and exterior doorways; weatherproof.
(See Figures 38C and 38F).
2) component jamb: weatherproof,
durable (Fig. 38C "nailed on stops").
RABBETED
JAM’3
NPILED-ON
9) Mortise the jamb, screw jamb and
screw hinges to jamb.
10) There should be l/8" to 3/16"
clearance between door and head.
STOP5
Figure 38C
!-‘a“ TO ‘/lb’
BEfWEEN
CLEARANCE
DOOtXf, HEAD
Procedure for Banging Doors
1) Before making jambs, take the time
to inspect a properly hung door; note
the hinge positions on door and jamb.
Figure 38E
2) Use solid, dry material. cut to
correct width, and if making a rabbeted door, rabbet with a saw to form
tongue and groove.
11) Assemble jambs on floor; nail and
glue; allow to dry for 24 hours.
3) To install hinges, lay out on door
first.
12) Assemble door and jambs.
for fit and clearance.
13) Remove hinge pins; lay door aside
4) Using the hinges as a pattern,
mark with sharp knife.
5) Mortise out the bed for the hinge
with a sharp chisel.
Figure 38D
6j Lay hinge in mortise, mark screw
holes, drill holes for screws. The
size of the drill should equal the
size of the shaft of the screws.
50
Check
ASSEMBLY
OF RABBETED
JAMBS
TO HEAD
Figure 38F
14) Before finally hanging door,
bevel edge on door handle side about
l/16”.
15) Shim jambs in rough opening using
shingles or wedges to adjust. Use a
level, carpenter's square, tape measure to check for plumb and square.
161 Nail through jamb with finish
Nail only hinge side first.
nails.
17) Hang door once again; check for
fit.
18) Adjust jambs for l/16" clearance
and then nail all jambs into place.
bIARDWOOD DOOR
S\LLS
\NOlCATE
WOOD CONSTRUCTION.
ELEMENTS
AND PROCEDURE
ARE
APPLICABI-E
Tt, MASONRY
CONSTRUCTION.
DEl-AILS
BAS\C
‘AL” BEVEL WITH
HAND PLANE &.ISTRlKE SlDf2 OF DOOR.
Figure 38H
Figure 38G
51
CHAPTER III
ALTEXNATIVE BUILDING MATERIALS AND
TECENIQUES
Introduction
The local alternative building materials industry should be reinforced
to produce materials that are affordable to most people, and particularly
for home builders in African countries. Due to either the high costs
and/or scarcity of typical building
materials, there are serious constraints affecting the construction
industry in Africa generally. Thus
while a respectable volume of building activity is evident, it is not
nearly sufficient to meet the needs
for appropriate housing in the region.
open to the destructive elements of
climate, and further reducing the integrity and quality of the buildings.
Protracted delays caused by shortages
have, in many cases, made a mockery
of efficient construction procedure,
management techniques and cash flow
principles.
In terms of long range planning, national governments and their districtlevel public works and construction
authorities should be encouraged to
support the testing and production of
alternative building materials by local builders and entrepreneurs. As an
example, if government adopted less
strict regulations for rural building
codes, rural builders would be encouraged to develop and use local
materials, thus cutting the costs of
transport, labor and the volume of
materials which needs to be imported.
A certain volume of imported materials will continue to be brought in
for many years, because of the desire
for manufactured and processed materials, and because local industries
are not producing building materials
of adequate quality and in sufficient
volume. A broad effort towards upgrading and encouraging the production of building materials from local
raw materials would save money over
the long term, and would create gainful employment and business opportunities for local people. Above all,
it would bring the cost of building
materials within reach of the large
numbers of people who want and need
improved housing for their families.
In recognition of the need for alternative building materials, and the
very real potential for local materials to help overcome shortages and
to generate construction activity at
local levels, Zhe Experiment in International Living CEIL) and the Bannakaroli Brothers have been working
together at the Kiteredde Construction Institute (KCI). A major focus
has been on improving the traditional
techniques and mixes for brick and
block making, alternative mortars and
concrete, local plaster mixes, the
use of anthill kilns, and the production of local paints from soils and
plants in the area.
In Uganda, construction projects over
the past several years have progressed by fits and starts, due to the
shortages of materials. Techniques
have been used to stretch cement as
far as possible, ultimately affecting
the quality and structural integrity
of the structures. Further scrimping
or lack of adequate materials have
left structures unfinished for months
at a time, thereby leaving buildings
This chapter describes some of these
techniques and mixes, and also includes a section on the basic mathematics needed for construction. It
should be clear that some of the mixes and formulas would vary from one
area to another, depending on soils,
vegetation and other factors, but the
basic approaches employed can be adapted to other areas, raw materials
and conditions.
53
Local Material Mixes
Mortar Cement
The following mixes have been tested
and improved over the past five years
in a number of different building
projects in Uganda. Structures such
as houses, school classrooms, storage
and work sheds, dormitories, toilets,
cook houses and food storage facilities and farm buildings have been
constructed at a very reasonable cost
as compared with building with Portland cement, iron roofing sheets and
other imported or manufactured materials.
1
2
4
6
The use of these local materials in
actual construction projects proves
their viability, and economic suitability for many or most African settings. In addition, the resulting
buildings are just as attractive and
structurally sound as most of the
structures built in rural areas and
small towns.
The clay that is used in the following mixes is the same clay used for
brickmaking, and should be prepared
for these mixes in the same manner,
described earlier, before being applied to the mixes. Following these
recipes is a section on Mixing Alter
native Cements, which provides the
information needed on techniques.
Concrete Foundation Using Local
Materids
Gallon of purified cow dung liquid.
Karai of wood ashes.
Karai of pure clay.
Karai of sea sand.
Damp-Proof Course
1 Gallon of purified cow-dung liquid.
1.5 Karai.of wood ash.
4 Karai of pure clay.
6 Karai of sea sand.
Foundation Mortar (from footer up to
the damp-proof course).
1
2
4
6
2
Gallon of purified cow-dung liquid.
Karai of wood ash.
Karai of pure clay,
Karai of river sand.
Karai of anthill clay can be added.
Inside Plastering
1 Gallon purified cow-dung liquid.
1.5 Karai of wood ash.
2 Karai of pure clay.
5 Karai of river sand*
* can also use a combination of 2
sea sand and 3 river sand.
Outside Plastering
1
2
2
6
Gallon purified cow-dung liquid.
Karai of wood ash.
Karai of pure clay.
Karai of sand (3 sea sand, 3 river
sand).
1 Gallon of purified cow-dung liquid
2 Karai* of wood ash (see Figure).
4 Karai of pure clay.
6 Karai of sea sand.
8 Karai of 314" stones.
Anthill clay, if available, can be
substituted for regular clay in this
recipe, and 2 karai of anthill clay
added to the above mixture will provide a very strong concrete. Anthill
clay and its uses are explained on
page 57 .
* 1 Karai = 10 Liters or 4.5 U.S.
gallons.
54
1 KAFW = IO LITERS
OR 4.3
Figure 39
US GhLLONS
Concrete for Ring-Beam (Lfntels)
Concrete for Floors
1 Gallon purified cow-dung liquid.
3 Karai of wood ash.
4 Karai of pure clay.
6 Karai of sea sand.
8 Karai of l/2” stones.
1
3
4
6
6
*
Gallon purified cow-dung liquid.
Karai of wood ash.
Karai of pure clay.*
Karai of sea sand.
Karai of l/2" stones.
Can also add 2 Karai anthill clay.
Cowduug Preparation Pits
The following drawings depict a cow
dung preparation pit for the making
of purified cow dung liquid.
The cow dung liquid is screened. In
pure liquid form when mixed with wood
ash and clay, it reacts chemically
and hardens within a 24 hour period.
,
I
I
Figure 40A
I
Figure 40B
I I
After constructing the pits, cow dung
is put into the top pit to a depth of
several feet. Add water and stir. Be
sure to take out all impurities such
as grass, sticks and other matter.
The water level in the top pit should
be close to the level of the screens.
After several days, more water and
dung are added, and the stirring Is
repeated. After collecting the purified liquid dung from the bottom pit,
it can be used in clay and mortar
mixes.
5) Attractive looking finished
product.
6) Durable if properly constructed,
and care in maintenence observed.
7) Adheres well with clay, wood ash,
sand and water; strong mortar.
8) Labor intensive, employing many
people.
The advantages to using these
alternative materials:
1) Variable clay qualities and how
thoroughly mixed.
2) Direct sunlight at the time of
application can cause the mixture
to dry too quickly, which can result in surface cracking, and
weakness in the application.
3) Excessive rain or other water running directly on the materials for
extended time periods may cause
some deterioration.
Locally available.
Little or no transport cost.
Law cost if one has to purchase.
Easy to use with some training.
Figure 41
Disadvantages are variable, depending
on skill level, technique in processing, and means of applying the material in building.
Mixing Alternative Cements
The basic steps in mixing all the
alternative cement and concrete mixes
are the same. The techniques in mixing are very important. The following
steps must be followed through from
start to finish. In all cases, the
use of clean water is critical. Sand
and concrete stones have to be free
of dirt and impurities. Clean water,
sand and stones will adhere, bind and
mix well with the clay, if all steps
and Procedures are followed.
Below is the mixing technique which
should be followed for all alternative local cement mixes. Refer to
specific recipes for the different
mixtures and proportions.
Step 1:
Prepare working area:
a> make a level working surface in
an area with an adequate water
supply.
b) free the area of roots, grass,
trees, shrubs and other matter.
Step 2: Spread prepared clay on the
ground in a 3 to 5 foot circle.
a> add enough water to soften the
clay and make it workable with
feet and a hoe.
Step 3: Mix sand into clay by
sprinkling; add anthill clay, if
available.
Add wood ash, mixing with
a> should be very well mixed until
all sand and the chunks of soil are
well blended, smooth and sticky. When
the feet are pulled from the mixture,
and there is a suction sound, the
mixture is ready for the addition of
the cow dung liquid.
Step 5: Add cow dung liquid by
sprinkling and mixing at same time.
Step 6: After the cow dung liquid is
added and mixed well, add clean
stones and blend in by mixing thoroughly.
Step 7: The mixture is ready for
application.
ANTHILL KILN AND ANTEILL CLAYS
Anthill kilns have been known to be
used in Uganda for approximately 100
years. There are various regions of
Uganda, and Africa in general, where
anthills are plentiful. In the wetter regions of southern Uganda, the
use of anthills as a source of excellent clay and to make natural kilns
has been very successful, due to the
availability of water and the large
numbers of anthills, which are sometimes as high as 12 feet above ground
level.
The soil in an anthill is basically
processed, regurgitated soil. After
the ant has chewed the soil and processed it, a saliva coating is left
on the particles of soil. This saliva
reacts with the chemical properties
of the soil, and after exposure to
the sun, hardens firmly. The chewing
motion and process mixes the soil as
one would mix clay from a pit with
one's feet, or with a hoe. This premixed clay provides desirable qualities for brick and clay moulding.
Once dug, the clay will be very hard
and chunky. The clay chunks should
be placed on a cleared, flat surface.
Water is added, depending on the dryness of the soil, until the clay becomes sticky but not soupy. Mixing
with a hoe and with feet is necessary
until all stones are cleared away and
the soil chunks are dissolved to make
a smooth mass.
The sticky clay should be placed in a
pile at least 3 feet high, and from 3
to 4 feet wide. Water is added, and
the sides are smoothed down.
57
/
leaving 2 or 3 fireholes, depending
on the size of the anthill. The top
can be mudded or plastered over,
leaving space for 2 or 3 smoke vents,
which are approximately 2' square.
The anthill cavity will provide space
for approximately 5,000 to 10,000
bricks. The anthill can be dug out in
such a way that it has three natural
sides, made up of the left, right and
back walls, which are from 2' to 3'
thick. The front side is open. The
depth, both downwards and to the back
wall, will be determined by the size
of the anthill and the nature of the
terrain. The three closed sides act
as perfect insulating walls to hold
in the heat when the kiln is fired.
Advantages of anthill kilns are:
1) The clay is on-site; no transport
costs.
--
Figure 43
After smoothing down the clay pile,
it should be covered with grass, and
then sprinkled once again with water,
depending on how hot the weather is,
and also the season of the year when
the work is taking place. More
moisture is needed in the dry season.
The pile should be allowed to stand
and to ferment for 7 to 10 days, and
then broken down and mixed thoroughly
again. Next, it is piled up again
into the same kind of pile, covered,
and allowed to ferment again for a
few more days, or until one is ready
to use the clay.
At this point, one is ready to set up
a moulding bench and to begin the
moulding process, described in an
earlier section.(See page 10).
After moulding, the bricks should be
dried in the sun for at least two
weeks.
After drying is completed, stack the
bricks in the excavated anthill,
58
2) Use less fuel and labor, thereby
reducing cost, effort, and procurement and transport of fuel.
3) Bricks are thoroughly burned due
to reduced heat loss, compared
with man-made kilns.
4) Considerable reduction in labor
costs for making bricks, because
the pit created by digging for
clay becomes the kiln.
Some disadvantages of anthill kilns:
1) It is impractical to make a kiln
from an anthill if there is a lack
of nearby water. If there is no
water, there is no way to mix.
2) Limited volume of brick production
depending on the size of the anthill (up to 10,000 bricks usually)
ANTHILL KILN
/
c/
,FRE
LHAMf3ER-
r’
Figure 44
Figure 45
59
LOCALLY AVAILABLE PAIN!l!S
AND PAINT
COLORS
4) Mix until the substance is a thick
blood-like consistency.
Paint from the soil:
5) Using either a hot or cold mixture, paint on surface with
brushes.
Local paints have been used in Uganda
and in many parts of Africa for several hundred years. There are two
ways to find, make and use local
paints : (a> from the soil itself, or
(b) from certain plants. However,
only two plants, the sweet potato and
cassava are in much use as sources of
paint in Uganda today.
Most of the soil colors for paints
are found in hilly, semi-arid areas.
The reason for this is that the excessive moisture near rivers and lake
beds makes soil color differentiation
and extraction very difficult.
Yellow, white, black, pink and red
are the most commonly known and used
soils. These are to be found in the
dryer hilly regions. Most of the
desirable colored soils for paint
pigments can be found at depths of
from 10’ to 30' underground. The
top 10’ or so are usually the subsoils, sand, gravel and different
variations of clays. The colored
soil.or soft-r:uzk~:ll be abundant
after the digging pit has been cleaned out and the colored rock removed.
The different colors come at various
levels and depths. Most of the rock
will be either yellow, brownish, rust
or whitish in colour. After extraction, the stone or soft-rock must be
pounded in a soft, talc-like powder.
Under normal climatic conditions, a
coat of this paint will last several
years before repainting is necessary.
Paint from plants:
As stated above, paints from cassava
and sweet potatoes are most commonly
used today. Both of these are root
plants and must first be pulled from
the ground after reaching their mature state. After they have been
harvested, clean the soil from the
roots and dry the plants in the sun,
usually from 1 to 2 weeks.
Making paint from plants:
1) Crush the roots to a powder until
there are no lumps.
2) Ready one gallon of cold or cooled
water; must be clean and clear.
3) Add 4 kilos of the well-crushed,
powdered root powder.
4) Bring to a boil. (Substance will
be blood-thick).
5) After 30 minutes of boiling, add
l/3 gallon of banana juice*, and
continue boiling for 15 minutes.
6) Let liquid cool. After cooling
you are ready to paint.
Making paint from soil:
Wing
1) Boil 5 gallons of clean, clear
water.
2) Add 1 pound of salt.
3) Then add 2 Karai of the powdered
stone and soil, the color of your
choice.
60
banana juice:
Collect two bunches of sweet bananas,
and allow them to become over-ripe.
Put freshly cut banana leaves on the
ground and start to crush the bananas. The crushing process should be
done with a handful of green grass in
each hand. The grass will collect
the juice, which can then be squeezed
from the grass into a container.
The banana juice acts as an adhesive
which is necessary to hold and bind
the materials in the paint together.
If a very sticky adhesive is desired,
allow the juice to sit in the container for several days before blending it into the paint mixture.
In place of banana juice, rotten banana stems can also be used as a
binder, again by squeezing to extract
the juice. If there are no bananas
in the area, sugar cane can be substituted, Boil it, let the juice dry,
then crush and boil with water.
Local Paint Brush: Palm tree leaves
can be used to make a paint brush.
1) Cut several green leaves from the
tree. Crush with stones until the
leaves are very stringy.
2) Put into cold water and soak for 3
to 5 days, until soft.
3) Take out of the water and squeeze,
and then roll until it sticks together.
4) Wash or rinse in cold water.
5) After washing, dry out the leaves
for several days under the sun.
6) After drying, form into a brush,
cutting the leaves to the desired
length.
7) Tie on to a piece of wood, which
is the handle, and begin painting.
61
CHAPTER IV
BASIC MATHRMATICS AND CALCULATIONS FOR COWXRUCTION
MATHEMATICS
Fundamental Ideas in Geometry:
Many of the basic ideas in geometry are used by people every day. A contractor uses geometry in dividing his site into slabs, in figuring concrete
and in planning a roof. The contractor continually makes use of geometric
principles. He knows that he cannot turn a five-sided nut with an ordinary
wrench. He is familiar with the circle, the square and various geometric
forms as they enter into tools and land usage. When he does carpentry, he
uses geometry constantly. Every use to which he puts his square depends upon
geometry. We see geometric forms of utility and beauty on every side, in
forms of nature, in buildings and bridges and in the field. In the study of
geometry we are concerned with these forms in classifying and naming them, and
in applying the facts of geometry in a definite and systematic manner to
practical problems that arise in our work.
Angles:
Two straight lines that meet at a point form an angle, See Figure 46. The
idea of what an angle is, being a simple one, is hard to define. One should
guard against thinking of the point where the two lines meet as the angle.
This point is called the Vertex of the angle.
The two lines are called the Sides of the angle. The difference in the direction of the two lines forming the angle is the magnitude, or size, of the
angle. An angle is read by naming the letter at the vertex and at the ends of
the sides. When read in the latter way, the letter at the vertex must always
come between the two others. Thus, the angle in Figure 46 is read "the angle
B" , "the angle ABC", or the "angle at B."
The symbol < is used for the word angle.
angle ABC and <A for angle A.
In this way we write <ABC for
If one straight line meets another so as to form equal angles, the angles
are Right Angles. In Figure 47, the angles ADC and BDC are each right angles.
If a right angle is divided into 90 equal parts, each part is called a Degree.
It is usually written 1".
B
/
Oit
Figure 46
4
Figure 47
63
Applied Geometric Formula for Area and Volume:
The importance of a geometrical form in the study of practical mathematics
is determined to a great extent by the frequency of its occurrence in application. In construction work, the rectangle is more frequently seen than other
forms. There are also several other geometric shapes that are important. The
following shapes and formulas have been identified as useful to builders.
Area of a Rectangle:
Find the area of a rectangle 6 feet x 3 feet.
h=LXW
A = 6 ft. x 3 ft. = 18 sq ft.
<
----
L
6’
Figure 48
Area of a Parallelogram:
Find the area of a parallelogram.
H=
2 ft. and L = 5 ft.
/f----p;
A=HxW
A=
2 ft. x 5 ft. = 10 sq. ft.
I
w
-
+----Y
Figure 49
Area of a circle:
Find the area of a circle with a 3 ft. radius.
A=
Pi (3.1416) x r2
A = 3.1416 x 3' x 3' = 28.2744 sq. ft.
Figure 50
64
Surface of a Sphere:
_Find the square feet of surface area on a sphere 4 ft. in diameter.
S = 4 Pi (3.1416) x R2
D=R
7
= Pi x D2
= 12.57 R2
4=2R
2
S = 12.57 x 2 ft. x 2 ft. = 50.28 sq. ft.
Figure 51
Volume of a Sphere:
Find the volume in gallons of a spherical water container.
diameter is 14 inches.
"=4PixR3
'j
=
1 PI x D3
Inside
= 4.189R3
6
;
!
i
R=D
-2
=14=7
2
i
v=
.'\
/I)
4.189 x 7 x 7 x 7 = 1436.8 cu. inches.
1 gallon = 231 cu. ins.
V gallons
= .1436.8
231
Figure 52
= 6.22 gallons
Find the area of a trapezoid:
5 ft. across the bottom.
A=L+L
--
7 ft. across the top.
2 ft. in height.
xH
2
A=
7' + 5' x 2' = 12 sq. ft.
2
Figure 53
L
--
5'
65
Area of a Triangle:
-Find the area of a triangle with a base of 4 ft. and height of 3 ft.
1
A=
BxH
2
A=
2
1 x 4’ x 3’ = 12 = 6 sq. ft.
2
Volume of a Cube:
Figure 54
Find the volume of a cube 3 ft. on each side.
V =LxLxL
v = 3’ x 3’ x 3’ = 27 cubic ft. (1 cubic yard)
Figure 55
Volume of a Rectangular Prism:
Find the volume of a rectangular prism with a width of 3 ft., height of 3
ft., and length of 6 ft.
V=
3’ x 3’ x 6’ = 54 ft3
Figure 56
66
Circumference of a Circle:
Find the circumference of a circle with a 3 ft. radius.
C = Pi x D, or 2 Pi x R
x
2 x
C
ft.
=
57
of
Parallelogram,
Square:
=
a
b
A
A
by
by
Triangle:
%
a
2A
by
b
2A
by
where
A=
=
(a
b
c)
Triangle:
c =
a=
a2
2
v
b=
+b2
C
- b2
C2
-a
2
Trapezoid:
A
2
=l(a+b)xh
67
Circles:
A=
C=Pixd
1 Cr
2
d = C divided by Pi
A=
r2
C=2xPixr
A=
.+
d2 = 0.7854 d2
2r = C divided by Pi
Segment of Circle:
('/2
WI
2h
r=
w=
2
2
=
h2
h x (2r - h)
Ring:
Ar = A - a6 = Pi x R2 - Pi x r2
= (R2 - r2> = Pi x (R + r) (R - r)
Concrete Nixes and Calculation of Cubic Yardage
It is often necessary to repair broken concrete, to build a wall, or to
apply concrete to a surface. These activities require some knowledge of making
concrete: which is a mixture of cement, sand and gravel. The cement is the
bonding agent which hardens and holds everything together.
A good mixture for slab blocks or sidewalk repair is 1:2:3. This means
one part cement, two parts sand and three parts gravel. Concrete retaining
walls which support slopes, or stem wall in subfoundations, will require a
mixture of 1:2:2 (one part cement, two parts sand and two parts gravel).
The aggregate size used will depend on the type of work to be done.
Generally, aggregates should not be larger than l/4 the thickness of the
concrete slab to be constructed, but normally 3/8" to 1" gravel is used.
In concrete that is subject to severe wear, to weathering or to weak acid
or alkali solutions, 5 gallons of water per sack of cement should be used.
For concrete that is to be water tight, or subject to moderate water and
weather, use six gallons of water per sack of cement. For foundations, walls,
footings and massive concrete construction, seven gallons of water for each
68
sack of concrete is suggested.
dry.
It is assumed that the sand and aggregate are
A cubic yard is the measure used for concrete. Thus, the amount of concrete required for a given job will be computed on the basis of the total
number of cubic yards in the job.
A Problem to Practice With:
A foundation is to be poured for a building. The outside dimensions are to
be 20 feet by 50 feet. The foundation is to be 6 inches thick, extending 18
inches above a 30 inch wide and 6 inch deep footing. As an aid against overturning, the footing can be extended 18 inches beyond the outside of the
foundation.
How many cubic yards of concrete will be required?
aggregate size that should be used?
What is the maximum
Procedure:
1.
Draw a cross section diagram of the foundation as illustrated:
I-
yi?'
-I,
3~+-T
Figure 58
2.
Determine the aggregate size. The thickest cross-section is six inches.
l/4 x 6 = 1 and l/2 inches. Aggregate should not exceed this size.
(3/a" to 1" gravel is more typical).
3.
Determine the number of cubic feet in the footing section:
(23’ + 23’ + 48’ + 48’)~ +”
4.
Determine the nulllber
of cubic feet in the foundation section:
(20’ + 20’ + 49’ + 49’) x +’
5.
5 ft2
= 177.5 cubic feet.
= 13s ft. x 7
x g
x
18”
= 138 ft. x 3 ft2 = 103.5 cubic feet.
12
Total the two sections and compute for the total number of cubic yards of
concrete required:
177.5 + 103.5 = 281 cubic feet
281 cubic feet
27
= 10.4 cubic yards.
69
Calculating Strength for Wooden Beams:
There are three classes of beams illustrated.
and Cantilever.
They are Continuous, Simple
The Simple Beam (Figure 59) is supported at each end by a bearing wall.
Figure 59
The Continuous Beam (Figure 60) is supported in its' center. This type of
beam is always supported at one or more places along its length.
l
Figure 60
The Cantilever Beam shown in Figure 61 is rigidly supported at one end.
Figure 61
70
The strongest beam shown per foot of length is the continuous type. For
each of these beams the formulas below are used to determine the correct
dimensions.
Type of Span
Concentrated Load
At Center of Span
Uniformly Distributed Loads
Continuous
BM=lWL
6
BM=lWL
12
Simple
BM=lWL
4
BM=lWL
8
Cantilever
BM = WI,
BM=lWL
2
BM = Bending Moment of Span
W = Load in Pounds
L = Length of Span in Inches
Wood is of such variable quality that a safety factor'of 6 is usually used.
The average safe fiber stress (SFS) for most wood in use is 1200. Woods with
knots and other defects would have a lower figure.
BM
= SM (Section Modulus)
SFS
The section modulus of a rectangular beam is SM = 1 bd2
6
where b = the breadth of the beam in inches, and
d = the depth of the beam in inches.
BM
-=
SFS
lbd2
A Problem to Practice With:
A house is built of brick. One room is left open with an 11 foot width
opening. The space above the opening is enclosed in a cut stone wall 16
inches in thickness and 5 feet high. If the beam for this opening is made out
of seven inch material, what is the depth thickness required?
Procedure:
1.
Determine the weight of the load on the beam.
W=
-16" x 11' x 5' x 172 lbs. of !brick
-2
12"
ft.
W=
12,607.6 pounds, or approximately 12,600 pounds.
t--------/// +
Figure 62
2.
Refer to formulas on preceding page; select formula for a simple beam
with a uniformly distributed load and solve for BM (bending moment).
BM=
1WL
8
BM = 1
8
x 12,600 lbs. x 11 feet x 12 inches per foot.
BM = 207,900 inch-pound.
3.
Use 1200 for the safe fiber stress in bending for wood material. Dividing the bending moment (BM) by the safe fiber stress (SFS) for the
material gives a figure from which the size and shape of the beam can
be determined. This term is called the section modulus (SM). This
relationship is expressed by the formula:
BM
SFS
= SM
The formula for the section modulus of a rectangular beam is:
SM=lbd'
6
(b = breadth of beam in inches; d = depth in inches).
Thus, substituting in,
Or,
72
207,900
1200
=
173.25
RM =
SFS
1 bd2
6
= 1 bd2
6
Using b as 173.25 = 1 x 7d2
6
d2 = 173.25 x 6
7
d
=
d
=
= 148.50
the square root of 148.50
12.18 inches.
The dimensions of the beam are 7 inches width, and 12.18 inches depth.
73
SYHBOLS AND ABBREVIATIONS:
........... at
11
........... inch
C ........... degrees Celsius (centigrade)
cc .......... cubic centimeter
cm .......... centimeter
cm/set ...... centimeters per second
d or dia .... diameter
F ........... degrees fahrenheit
kg .......... kilogram
km .......... kilometer
m ........... meter
ml .......... milliliters
mm .......... millimeters
R ........... radius
@
USEFUL NUNBERS:
1 CU. ft. of water weighs 62.5 lbs. (approx.)
1 gal. of water weighs 8 l/3 lb. (approx.)
1 gal. = 231 cu. in.
1 cu. ft. = 7 l/2 lb. (approx.) or better, 7.48 gal.
1 in. = 25,4001 mm.
1 ft. = 30.4801 cm.
1 m. = 39.37 in.
1 kg. = 2.20462 lb. (avoirdupois).
1 liter = 1.05668 qt. (liquid) = 0.90808 qt. (dry)
1 qt. (liquid) = 946.358 cc. = 0.946358 liter, or cum dm.
1 qt. (dry) = 1101.228 cc. = 1.101228 liters, or CU* dm.
Pi - = 3.1416 = 3 l/7
UEIGBTS:
1
1
1
1
1
1
74
pound
lb.
short ton
short ton
metric ton
pound
=
=
=
=
=
=
16 oz.
453.5924 grams
2000 lbs.
907.2 kilograms
1000 kilograms
0.45359 kilogram
UEIGETS OF SUBSTAMZS:
Product:
Approximate Net Weight
In Pounds per Cubic Foot:
125
150
150
165
172
100
42
165
82
57
Brick Work
Cobblestone
Concrete
Flint Rock
Granite
Gravel
Gasoline (petrol)
Limestone (solid)
Limestone (ground)
Oil lubricating
Sand
Sand Stone
Water
1 foot
1 yard
1 mile
110
147
62.3
12 inches
3 feet
5280 feet
AREANEASURENENT:
1
1
1
1
1
1
1
1
1
hectare
acre
acre
acre
sq. mile
sq. mile
sq. mile
sq. kilometer
sq. kilometer
2.7109 acres
0.40468
hectare
4840 sq. yards
43560 sq. ft.
640 acres
259 hectares
2.59 sq. kilometers
0.381 sq. miles
100 hectares
75
CEAPTERV
pLANNINGANDMNe
INTRODUfXION
The planning of a building project,
and the management of the whole construction process from the initial
design to completion of the actual
structure, are very important. Lack
of knowledge of the elements of planning and management often lead to unnecessary problems. Accordingly, the
Kiteredde Construction Institute provides course work and practical field
experience for its trainees in these
subjects. The entire course cannot
be reproduced in this manual, but an
outline of its basic components might
serve as useful guidelines for builders and for other technical training
institutions. The material which
follows is designed for KC1 trainees
and graduates who are interested in
or engaged in the management of their
own small construction firms.
The statement was made at the start
that one purpose of this manual was
to serve people in areas where few if
any imported or manufactured materials are available. This remains true,
but it is important for KC1 students
and graduates to have a broader knowledge of the construction field, in
addition to knowing how to use local
materials well, and hence additional
elements are incorporated into the
curriculum and into practical work.
SECURING AUTRORITP
1. All local authorities who have any
responsibility for buildings and construction should be acquainted with
the project. The application to plan
and build should state the purpose of
the project , what the building is to
be used for, why it must be built,
its general size and location, and
what funds or financial arrangements
have been secured. Final permission
in writing should
basis
tions
be secured
on the
of approved
plans,
specificaand cost estimates
before
any
expenditure is made.
2.
Be sure
of
all
necessary
govem-
ment permission before
entering
into
any financial obligations. Almost invariably
this will
require
an official
government
stamp or signature
of
approval
on the plans or in a letter.
3. Inform yourself
in advance about
municipal or district building laws,
conditions,
fees,
inspections,
sanitation
and lighting.
Consider
the
costs
and compensation
for land purchase,
and the costs
and requirements
regarding
survey fees.
Paths or roadways through
a site are sometimes objectionable,
and the builder
must be
acquainted with the laws respecting
the opening or closing of thoroughfares.
issues
One must also
regarding
land
be aware
titles.
of
all
4. Financial
ability.
Consult
with
those who have erected
similar
buildings.
Compare prices
and conditions.
Be sure there
is enough money to complete
a sizeable
unit of the work before bringing
a crew of workmen to
the job.
Secure written
authority
for
purchasing
necessary
materials,
for
wage expenditures
and other costs,
and written authorization for expenditures
up to a specific
limit
or
ceiling.
Once authorizations
and
funding
are secured,
considerable
caution
needs to be exercised
to keep
within
understood
spending
limits.
As
actual
construction
a general
rule,
activities
should cease before
all
the money is used up, because
there
are many additional
expenditures
connected with the process
of closing
down a construction
job.
5. Consider
the reactions
of associneighbors
and others.
Although
ates,
they may have no legal
authority
to
hinder
the project,
they may feel
that the building
project
is offen-
77
sive to them or an inconvenience, and
may take actions which disrupt or delay construction efforts. It is important to identify potential problems in advance, and to work out the
necessary understandings prior to the
start of construction.
The following
calendar
or schedule
can be used as a guide to enable one
to see at a glance
the full
scope of
building
activities,
and to have all
the materials,
personnel
and preparation ready and moving along the work
path on a timely basis.
Scanning the Future
General Building Calendar
1 o One may not be able
to
build
very
much at one time. One can, however,
envisage and draw up a complete set
of buildings for a project, and then
build permanent units, one at a time
if necessary, until ultimately an
organized, efficient, attractive and
durable project has been developed.
2. The Unit System. It is much more
satisfactory to plan a properly appointed house or building, and to
build it section by section, as time
and money allow, over a period of
time. This is preferable to restricting the main plan at the outset by
planning something inadequate, which
requires
additions,
alterations
or
even abandonment, and can never be
brought
to perfection
completion.
or
satisfactory
3. Permanence.
Determine
that every
building
is designed
to be permanent.
To this end, lay out the whole site
with a 25 year perspective in mind.
Sketch
in
every
possible
building or feature.
additional
If it is nec-
essary
to live in some smaller
building until
the main dwelling
is erected, put up a garage,
workshop,
kitch-
en block or other outbuilding in its
proper place,
struction.
and of
permanent
con-
Survey of Operations
Start
to plan early.
The planning
process
includes policy, the design,
the method, the proper season, the
schedule,
the builder’s
arrangements,
orders
for materials
or gathering
them oneself,
and many other factors.
78
Necessity
for the project
to be
thoroughly
established.
Government approval.
Financial
ability.
Conference
of interested
parties.
Rough sketch.
Proper drawings
and specifications
Estimates.
Final authority
to go ahead in
writing
from Government or appropriate
authority.
Orders for all materials,
labour
and transportation.
Contracts
awarded.
Lumber sawed or purchased.
Bricks made.
Work and storage
sheds erected.
Make scaffold,
frames,
doors,
windows and built-in
cabinets
or
furniture.
Local materials
gathered.
Building
site
cleared.
Construction
begins:
Layout
Excavation.
Footings
and foundation
walls.
Concrete
mortar ant coursing.
Door and window frames set in
walls;
arches built.
Main walls built.
Begin roof frame.
Roof frame erection.
Ceilings
made and erected.
Plumbing,
wiring,
built-in
cup,.
boards,
etc.
Inside
plaster.
Doors and windows fitted
and
hung.
Concrete
floors,
verandahs,
steps,
foundation
pointing.
Interior
trim, screens.
Painting
and glazing.
Grading and drainage.
Inventory,
salvage,
completed
records, wind up and completion of
entire building project.
objective should be to design and
erect efficient, durable buildings
economically.
Policy
A wrong policy or attitude will produce trouble or difficulty in any
construction enterprise sooner or
later. It is suggested that a building policy be formulated, with the
following as a guide:
’ Efficiency. Efficiency means that
the completed structure can adequately serve the specific purpose or purposes for which it was designed. It
should have sufficient room for all
activity, and for furniture, equipment, special features, storage and
other needs. The plan should be
arranged so that all occupants will
have any and all reasonable convenience. Health should be safeguarded
by providing sufficient cubic air
space, ventilation, shade, privacy,
quiet, and protection from insects
and dampness. The builder should beware of curtailing the efficient:?of
a structure by overemphasizing o:
misapplying economy.
.
I
2. Durability. Ruskin says, “When we
build, let us think that we build
forever.” Most of us are not in a
position to build forever, but we can
at least build durably. Although we
may not be able to afford granite,
marble, bronze, or elegant tilework,
we should not on the other hand be
satisfied with shacks and huts for
dwellings, or inferior structures for
schools or health aid posts. There
should be sufficient durability to
withstand weight and stress, decomposition and weather, wear and abuse,
infestation by insects and invasion
by animals or man. Thus in terms of
structural integrity, a builder must
resist the temptation to save a few
shillings at the expense of the basic
strength of the building. It is false
economy to cut below sound construction and practical efficiency. The
4. Form and Finish. This means making
the most out of what is available and
necessary, and finishing the job as
attractively as possible. Good finish
work enhances the value of a building
property by giving it a pleasing appearance , as well as by preserving
it. Proper colours also contribute to
restfulness, light, coolness and general satisfaction.
Seeking Advice
There are many costly pitfalls and
problems in the planning and erection
of a building. Since the construction of a house or other building is
the major expenditure in a lifetime,
for many of us, we should make every
reasonable effort to secure the advice of an experienced builder. When
we must build without the benefit of
such advice, we should:
1. Carefully plan everything that
we make or build.
2. Make all changes and m+.stakes
on paper.
3. Place all the basic ideas on
paper for the benefit of those who
will have a part in the project, before, during and after construction.
Any building is an investment as well
as a utility. By thorough planning,
and the use of good materials, labour
and construction methods, one can
avoid unnecessary expense, inefficiency and dissatisfaction. As a general rule, mistakes in design and
construction are readily visible and
apparent, are costly, and tend to be
permanent.
Selecting a Site.
It is unwise to make the final decision on a building design until the
site has actually been secured, and
all its important features are known.
79
A house which is satisfactory on one
site, may not necessarily be as good
or as acceptable on another site. One
should gather and assess information
about the conditions on and around
the proposed site in all seasons with
respect to its suitability for:
1. Health: Temperature, humidity,
altitude; the time, force or value,
and the direction of winds; soil
erosion; swamp; rainfall; the prevalance of disease; proximity to unsanitary conditions in nearby places
over which you have no control; depth
of soil; the presence of large rock
masses which radiate heat; the presence and value of trees; whether the
site is on a hill or situated on a
plain or in a valley; its proximity
to other buildings, and the character
of those buildings.
2. Work: Accessibility to and from
other people, centres of population
and appeal, government favour; proximity to places of work and other
jobs.
3. Building Conditions: Enquire
about supplies, labour, weather,
building by-laws, restrictions and
plans for future developments. On
occasion an area is found which is
quite unsuitable For a building or
a compound.
4. Environment-: This is particularly
important in areas which have been
built-up or which are crowded. The
proximity of the proposed site to
congested areas, or to institutions,
roads, rivers, heavy lorry traffic,
dust and air pollutants, and other
features should be examined.
Business Detail
Estimates: If a completed building
costs more than originally expected,
it is generally due to the lack of
estimates, or the lack of care or experience in their preparation. An
80
outline guide for estimates should
include :
I.
II.
III.
VI.
V.
VI.
VII.
VIII.
IX.
X.
XI.
The Compound or Site
Lumber
Wall Materials
Cement
Roofing
General Hardware
Imported Goods
Local Building Materials
Building Equipment and Tools
General Wages
General Expenses
I. The Compound or Site
1. Clearance, grass, bush, trees,
rocks, buildings.
2. Wells, digging, preparation of
bottom, top, sides of well.
3. Roads, entrance to compound or
site, access.
4. Grading, cutting down knolls,
filling holes, terracing.
5. Draii;age,ditches, culverts,
bridges.
6. Equipment for digging,cleaning,
hoisting, climbing, clearing.
II. Lumber
1. Production, sawmill or sawyer
contract, saws, file, carriage.
2. Uses:
a. Temporary dwelling and furniture.
b. Equipment, ladders,scaffold, saw
benches, brick making moulds, tables,
hardware, racks for materials.
c. Shop, tool sheds, workbenches,
material shelters.
d. Frames, doors, windows, wall
ventilators, built-in cupboards,
battens, door and window stops.
e. Roof, posts, verandah and wall
plates, rafters, ties, struts,
purlins.
3. Ceiling.
f. Ceilings, joists, support beams,
trap doors and frames.
5. Miscellaneous: stove pipes, sinks,
brackets, shelves, funnels, weather
strips, furniture reinforcement,
ventilators, chimney caps, roof
flashing.
g. Doors, windows, shutters, screen
frames.
h. Miscellaneous: beams, sills, lintels, trusses, stairs and steps.
i. Furniture and equipment.
III.
Masonry
1. Stone for footings, foundation
walls and main walls, verandah and
floor.
2. Brick for all purposes in all
buildings; manufacture and transport.
3. Concrete block construction. Cement, sand, water, machine manufacture or rental, contract, transport of blocks, curing.
4. Other types of wall, materials
and labour.
IV.
Cement and Lime
AI
4. Doors and windows.
VI. General Hardware
1. Common nails for equipment, tool
boxes, stores, benches, brickmaking
or block-making equipment, lodgings,
scaffold, bracing, frames, doors and
windows, roof framing, ceilings and
furniture. Old nails for driving into
brick wail:? to hold plaster. Special
nails for furniture. Galvanized nails
for roofing. Tacks for screens.
2. Screws for hinges, hasps, locks,
frame ties, fittings.
3. Bolts for roof, roof iron,equipment.
4. Hinges for doors, windows, traps,
screens, cupboards, hooks and eyes,
door bolts and locks.
5. Handles and knobs for doors,
drawers, shutters.
1. Floors.
2. Foudations, footings, pointing.
6. Bale or strap iron for frame ties,
ceiling supports, trusses, roof ties,
repairs, ladders.
3. Plaster.
4. Miscellaneous: window sills,
platforms, well tops, steps, water
tanks.
5. Lime for plaster, whitewash,
mortar.
V.
Roofing
7. Wire, mosquito screen for doors
and windows, ventilators and food
storage.
8. Water system, pipes, taps, fittings, tanks.
9. Expanded metal or woven wire for
concrete reinforcement; thief guards
for windows.
1. Sheet metal formant coursing.
2. Roofing, including ridging,
gutters, down pipes, facing.
10. Rod iron for concrete lintel
reinforcement, water tanks, roof
frame pins, shutter fasteners.
81
General Wages
11. Electrical supplies of all kinds.
x.
12. Fire and lightning protection
equipment.
1. Excavation fill, carriage of rock
or mud from a distance, general labouring on the building, clean up.
13. Health and sanitation necessities.
2. Masons.
14, Paints, oils, varnishes, stain,
filler, turpentine, colours and pigments, lime, cement paint, glass,
putty, tar, points, sandpaper,
brushes for all purposes.
VII.
Imported or Purchased Goods
1. Construction lumber, wall boards,
doors, windows.
3. Carpenters.
4. Concrete work.
5. Plumbing.
6. Sheet metal work.
7. Electrical work.
8. Painting and decorating.
2. 111 house hardware.
XI.
3. Furnishings, curtains, blinds,
rugs and mats.
4. Equipment, pump, building tools
and garden tools.
VIII.
2. Sand for all purposes.
3. Water for mortar, concrete, sand
washing, concrete curing, plaster.
4. Carrying receptacles for mortar,
cement, water, mud.
5. Mats and poles for temporary
shelters.
6. Lumber (timber) for scaffolding
and roofing materials.
Building Equipment
1. Picks, shovels, hammers, axes,
crow bars, buckets, wheelbarrows,
sand screens, trowels, level, stringline.
82
1. Government fees, expropriations,
survey, licenses.
2. Builder's expenses, travel,
equipment, accommodations.
Local Building Materials
1. Rock for foundations.
IX.
General Expenses
3. Transportation of materials
and workmen.
4. Build or rent quarters for
workmen.
If possible, secure a copy of cost
estimates of a building similar to
the one being planned. A review of
these estimates and actual costs will
bring out many items which should be
factored into the new building plans,
and which may not have been included
in the initial estimates. The comments of the experienced builder regarding costs, as well as the conditions which helped or hindered the
other construction job, could be
very helpful in thorough planning.
A building similar to the one being
planned, or exactly the same, in a
different locality or on a different
site, may have cost considerably more
One should gather as much
or less.
information as possible about actual
building costs in the locality where
the building project is planned.
Orders
The order is the final quantities
list, giving only the particulars
necessary to a business transaction
in the purchase of materials.
To get the best service from your
supply dealer, state for instance
that 20 pieces of 2” x 6” are required for scaffold, 20 for frames,
20 for roof, 10 for doors, 10 for
furriture, so that the right grade of
lumber for each type of work will be
supplied, if possible.
Write every order, for record purposes at least, including orders for
trucking and for water, mud, stone,
sand, and other materials. Then check
up afterward and see that the full
amount delivered is shown under the
heading "materials ordered". Whether
the material is ordered or not, paid
for or contributed, write it down.
Always keep a copy of your orders.
Contract8
Here again an experienced builder's
advice is invaluable. Too many contractors are unable to give a fair
figure or tender of the work. If you
bid too low and one accepts your tender, there will be financial loss and
bad feeling, or possibly there could
be fraud and hard feeling the other
way. It is poor business ethics to
take advantage of an inexperienced
and financially hard-pressed subcontractor or artisan by accepting a
palpably low bid and trying to hold
him to it.
Conversely, of course, contractors
may try to take advantage of inexperienced builder-owners. Hence it
is better for all parties if quantities and qualities of materials, and
cubic content of concrete and masonry
work are submitted to the contractor.
It is also well to have at least two
subcontractors bid for one job. The
lowest tender is not necessarily the
best. Nor is the highest bid a guarantee of good work. The best contractors are the best guarantee, and
the best measure of a contractor's
quality is previous work performed
and the reports from his clients.
The contract, in writing, should
always include:
1. The name of the final authority
on the job, the one from whom the
contractor takes orders and who is to
interpret the plans and specifications for the owner. There should be
also the name of a mutually satisfactory third party to adjudicate in
case of difference of opinion between
the contractor and the building superintendent mentioned above.
2. The interpretation of drawings
and specifications. Generally the
figures on the drawing are to be followed. State who is financially responsibile if the contractor makes
the wrong interpretation of two posible meanings, when two different interpretations are possible. He should
seek interpretation if he is in doubt
and pay for misinterpretation if he
goes ahead on the wrong line.
3, The contractor's responsibility
with respect to care of materials,
equipment, and bad workmanship.
4. What amounts are to be paid as
the work progresses, when they are to
be paid, and on what basis. In this
connection it is well to have the
contractor's requisition for Saturday's wages in your hand on Friday
night.
83
5. Bonus, if any, for completing the
job by a certain date, and converselY9 a penalty clause for going beyond
a certain date.
6. Extra work. Any alteration or
addition to the plan after the contract has been awarded. One solution
is to agree on paying the contractor
10% or 15% on the cost of such addition or alteration. But the order
for the extra work must be in writing, each party having a copy.
7. The contract may also have to
include some arrangements about the
kind of labour employed. Certain
groups may have been found to be
troublesome.
Accounting
It is excellent practice to have an
account book for each building in
which to record every expenditure and
every item used. In other words, a
record of the true cost. This record
will be of assistance to yourself and
other builders later on. Make remarks
which will throw light on the conditions under which you carried out the
project.
If all dates are properly entered,
the account will show the amount of
time taken for the whole job. There
should be a record of how long the
foundations, walls, roof, and concrete work have taken in the process.
The pay book itself may well be in
duplicate, showing each man's pay
day. The copy of this can be sent to
the mission office. The account
should show the quantities, grades
and costs of all materials. Finally
make a list, with costs, of all leftover materials and equipment. Complete the whole project in every detail as soon as possible and wind up
all accounts.
Care of Materials
1. Lumber: Lumber should be
stacked on strong, straight cross
pieces about 2'6" apart so that when
the pile is completed it will be held
in its original straight position. If
the lumber is very green it should be
stacked with considerable air space,
but not in such a way that the lumber
will warp.
Protect the wood from sun, rain, pilfering. The ends of the sticks tend
to split. It may be necessary to
hang a mat or old cloth over the end
of the pile and soak it occasionally.
It pays to be on hand to supervise
the drawing of stock. See that wood
suitable for each job component is
taken, otherwise the best will be
taken first, and the final tasks will
be carried out with wood of lesser
quality. See that the pile is left in
a neat condition. If sticks get left
here and there during the day, have
them picked up and stacked again.
They will soon warp if they are left
out in the open.
2. Cement: This material is so
susceptible to moisture that it is
very difficult to keep it strictly
dry through a rainy season. Keep it
off the floor and in the driest room
available. If it has to be kept over
the rainy season, attempt to seal it
in absolutely waterproof containers.
Cement absorbs moisture from the air.
A little period of exposure may not
do much harm to cement in ordinary
containers, but a whole wet season
would be fatal. When cement granulates it deteriorates in quality,
whether it can be reduced to powder
again or not.
3. Hardware must be kept dry in
proper receptacles. Nails should be
kept sorted and under lock and key.
See that the nail boxes are stocked
each morning. This will help you to
keep a check on the quantity being
used.
4. Door and window frames should
be well braced, stacked on a level
floor, or on bars, and protected.
5. Mud bricks can be made ahead of
time. If there is no danger of rain,
they may be neatly stacked around the
building site within easy reach of
the labourers serving the masons. If
there is danger of rain damage, pile
the bricks as compactly as possible,
cover them, and drain the base of the
pile by an encircling trench.
6. Roof iron is not only expensive
but mishandling seriously interferes
with its usefulness. Hence every precaution should be taken to have it
carefully handled from the suppliers.
It must not be thrown down on end,
either in the bundle or in separate
sheets. If carriers bring it by head
load, ensul:eif at all possible
against their stealing the banding
iron, or bending the sheets double to
make handy head loads. This latter
practice results in distortion of the
corrugations and makes a tight joint
roof almost impossible.
operations as needed, without fail.
Lack of water as well as other materials, for even brief periods, adds
heavily and unnecessarily to labour
costs. If necessary secure drums or
make some other provision for a constant supply throughout each day.
Always have water in good supply
throughout each day. Always have
water in good supply before the water
carriers go home each night.
Labour
Selection of Labour: The following
factors should be kept in mind when
making a selection of labour.
1. Season. All seasons are not
equally suitable for building operations for various reasons. There are
the busy seasons when labour is in
short supply, the wet season when
travel is difficult, and seasons when
housing is scarce. At times feasts,
fasts, observances and other religious customs interfere with building
programs.
If transportation is uncertain for
any cause at the critical period, be
sure that everything is brought to
the site well ahead of time.
2. The Number Employed: This
should depend upon one or more of the
following: the urgency of the particular project; the amount of time at
the builder's disposal; his ability
to handle a work crew; distance from
which a crew must be brought; the
possibility of sharing this cost of
transport with someone else in the
more or less immediate neighbourhood;
the equipment on the job to keep the
men busy if they did come; and the
number of local labourers available
at the time of building is an item to
be considered, especially in respect
to supplying the masons at all times
with all the materials they require.
When time is not a vital factor, the
work force brought from any considerable distance must be cut down to a
minimum.
Make provisions for an adequate
supply of water for all building
3. The Various Types of Labour
Employed: Try to have a crew which
Care in design through preparation
and adequate supervision are essential in keeping down building costs.
Everything that can be brought and
prepared for use before the building
crew comes will help to get the job
off to a gbsd start. All the lumber
should be on hand. If possible, all
scaffold, benches, shelters, frames,
doors, windows, lintels, arch forms
should be prepared by the time the
workmen arrive.
85
is accustomed to your speech and to
your methods. This applies particularly to those who are kept busy
building. Following this have a
nucleus of at least one good mason
and one good carpenter who have been
with you previously. It is better to
have at least four masons who can
build plumb corners, and two carpenters who are experienced with doors
and windows, and two who are good at
roofs. Mason apprentices should be
restrIcted to one for every four
bricklayers. Carpenter apprentices
are more acceptable and may be employed at a rate of one to every
three or every two of the skilled
men. Usually labourers are not imported but occasionally the local
labourers are so unused to cement
mixing and kindred jobs that one or
two strong, experienced and reliable
men may profitably be brought in.
Ethnic group wrangling may be serious
enough to restrict the labourers on
any job to one group. That is, labourers and artisans on a job may be
best drawn from one group, or labourers from one and artisans another.
Labour Agreements
When labour is first engaged, a fair
idea should be given to the prospective workmen about the location of the
job; the purpose and status of it;
its estimated duration; the general
wage level and hours of work; sick
pay, overtime and travel pay, if any;
whether or not a man may bring his
wife, and on what terms; in a work
crew of 5 to 6 men, it is frequently
necessary and useful for one of the
wives to cook for the group; the food
supply issue should be addressed with
the work crew, and some satisfactory
arrangements should be worked out to
avoid having workers upset on the job
because of the absence of the kind
and quality of food to which they are
accustomed; rental and lodging arrangements must be worked out for all
workers, and particularly when men
86
are already paying rent on their own
homes. The best rule is to show the
workmen that they can expect to be
fairly treated, and make clear that
they should expect to produce a quality effort in return.
Labour Relations
It is important to be well informed
about the labour viewpoint, temper
and climate before the job begins.
One should become familar with the
labour laws of the district and the
country as a whole. A misunderstanding of the regulations and customs,
or the occurrence of an incident related to the job, can lead to widespread and long-lasting trouble. In
many past cases, such episodes have
resulted in harmful testimony, and
have at times adversely affected the
labour market and labour relations
over a wide area, and have seriously
disrupted the construction project.
Thus, it is important to be judicious
and careful about discipline, such as
dismissing a worker abruptly for a
minor offense. It may be wiser to
separate the man from the other workers by placing him in a different job
for a time, and then if circumstances
so indicate, release him on pay day by
telling him his services are no longer needed. Be sure he receives the
correct amount of pay, and if it
seems advisable, he might be given a
small gift on departure as a gesture
of good will. One should never resort
to physical force, nor lay hands on a
workman if it can be avoided. In serious cases where physical restraint
is necessary, let the other workmen
attend to him.
In most areas it is not justifiable
to set one single price for a specific trade. Wages vary considerably
between trades and from one district
to another. One need not pay the
highest wages, but the contractor or
builder nearly always loses in the
long run, in various ways, if wages
are set at the lowest end of the
scale, and if the poorest workmen are
hired.
Remember that mixing concrete all day
by hand is very heavy work, and it
can be a mistake to try to force a
hustling pace over extended time periods. Willing workers should be allowed to have a breathing spell occasionally.
Before work commences, some mention
should be made of the conduct expected. Many of the men, if not all, will
have been accustomed to very different working conditions as well as
leisure time regulations. Loss and
waste due to deliberate disobedience
of an order should be made up, as far
as possible, by the man responsible.
Pay should be cut for deliberate
idleness, excessive lateness and for
quitting early. The incident in question should be pointed out to the man
at the time, an entry made in the pay
book, and a fine deducted on pay day.
Since this tends to be a distasteful
experience for the worker, he should
be given an opportunity to make up
the time through overtime work.
In a well managed project, the work
day starts on time, and each day's
work ends on time. Be punctual.
Absolutely no building materials
should be appropriated for the private use of the workman. There is a
tendency for them to pick up scraps
for personal use, but such scraps are
worth money and have many uses, not
only during the specific construction
operation, but the next one and the
one after that, If one of the workers
wishes to make use of scrap material,
he should ask for it, and failure to
do this ought to be punishable. A
good practice to minimize temptation
is to pick up all cuttings, nails and
other useable scraps daily or as often as is practical.
Occasionally artisans at work 01~a
project will be asked by outsiders to
do piece work for them after hours.
It is considered disadvantageous for
an employer, (a) if the work is being
done at the work site or compound, or
(b) if the carpenter, for example, is
sharpening his tools on employer time
and using nails and other materials
from the project to carry out this
extra work for someone else. It is
important for a manager to have some
control over such practices, since it
affects his project directly. The
manager should request or demand that
each artisan keep a clear record of
all extra pay or monies received for
extra work of this kind while employed on the project, from the date of
hiring until finally released.
It should be made known at the start
of the project that thieving and
burglary will be dealt with severely.
Such negative activities as fighting,
gambling, drinking, quarreling with
food vendors on the compound or work
site, or bringing a woman to the compound, should be forbidden at the
very start of the project. Also, carousing, fighting and other objectionable behavior in relation to the
townspeople should be discouraged.
Discourage advance payments, or salary advances, especially after the
workmen have had one pay day. Have
the pay made up in advance, and have
it carefully checked, so that when
the wages are handed out on pay day
each man will receive the correct
wages for the work performed, and
there will be a minimum of misunderstanding, disagreement and argument.
Pay the workmen every shilling that
is due to them, from the start of the
project until the final payday. The
arrival of pay day is an important
event for the workmen, and an important moment in the life of the
project. It should be carried out
smoothly and well, and should be a
positive, happy event.
87
Supervision of Labour
Proper technical direction can be a
problem and needs constant attention.
It is difficult to obtain satisfactory performance or results without
a strong foreman or one person's full
time supervision of labour. Someone
in a position of responsibility and
authority must be on hand to order
and check on materials, to employ
local labour, and to attend to all
the details of correspondence, cash
flow, time, wages and other duties at
the work site.
Invariably the cost of wages goes up
there is inadequate supervision.
This is due in part to inexperience
and lack of clear insight into the
whole
process by members of the work
force, and due in part to a natural
tendency to let down when left alone.
Often the artisan may not know what
to do next, or may not clearly understand the instructions he has been
given, particularly if working for a
new employer or supervisor. In an
attempt to avoid many unnecessary and
costly mistakes due to misunderstanding, the following techniques have
been developed and widely used with
good results. They are not intended
to reflect negatively on artisans or
labourers in any part of the world,
and in fact have the effect of improving rather than disrupting labour
relations.
when
The Building Superintendent's Five
Commandments
1. Tell the workman what is wanted
several times, very plainly, and only
tell him one thing at a time.
2. Show the workman what is wanted.
Put your hand on the material, mark
it if necessary, and demonstrate the
procedure by actual example, so that
there can be no question about what
is intended.
88
3. Stand by the workman, or visit him
frequently, to see if he is carrying
out his instructions, or if he is unclear about exactly what needs to be
done. This ia particularly important
if this is a new job or new procedure
for the workman.
4. Avoid asking questions which can
be answered by simple direct observation or investigation. An employee
may tend to try to please by giving
what he thinks to be the answer indicated by the question, but he may
misrepresent the facts in order to
try to satisfy the supervisor's
question. An experienced supervisor's direct observation can save
time and eliminate confusion.
5. When a component of the project or
a piece of work is finished, it can
be a good practice to declare it to
be complete, and move the workman or
team on to the next task. The purpose is to avoid wasting valuable
work time by overworking a specific
task, and to avoid the possibility of
unintentional damage to a portion of
the project which has already been
declared satisfactory.
In approaching the role of supervisor
it is important to state clearly,
repeat again, and re-emphasize that
orders given have a clear purpose and
must be carried out as given. Orders
should not be changed because the
workmen have a different opinion. At
the same time, a good supervisor will
assure his workmen that if they do
have a different opinion, and if they
do think that an order is faulty,
then they should call the supervisor's attention to it. If they are
correct, and the original order is
flawed, the supervisor should thank
them for pointing out the problem and
should revise the order. As a general rule, the piece work principle
should be followed, since it tends
to be mutually supportive and helpful.
Direction or Manipulation of Labour
Thorough preparation of the entire
project as a whole, and for each
particular component and job, will
pay rich dividends in efficiency and
is well worth the time and effort.
Have all equipment, materials and
supplies ready for the workmen every
time they come to the job site. When
the workmen have made a good start on
one section of the work, the next
stage of operations should be thoroughly prepared so that there will be
no loss of time or efficiency when
they complete the first section and
are ready to move ahead with the
next.
Keep each artisan employed within his
own skill field to the extent possible. In other words, let labourers
prepare scaffolding, rather than
having skilled masons do it. Perhaps
one of the masons should supervise.
As a general rule, do not allow a
carpenter to spend time doing what
his apprentice can do, and do not let
an apprentice waste time doing what a
labourer can do. In the same vein, it
is often the case that a simple piece
of apparatus can be employed to hold
material that is usually held by a
labourer, thus freeing the labourer's
hands to carry out other tasks.
In cement work, careful forethought
and constant supervision is needed
to prevent confusion, delay and
waste. The supervisor must keep every
part of the operation moving forward
smoothly and efficiently.
Simple interest is usually calculated
at a certain precentage rate per
year. The base on which the interest
is calculated is called principal. In
reckoning interest, time has to be
taken into account. The simple interest on a sum of money for one year
at a certain rate is the prinicipal
multiplied by the interest rate. For
a two year period, it is twice as
much. For any period of time, it is
the interest for one year multiplied
by the number of years.
P stands for Principal. I stands for
Interest. R stands for percentage
Rate. T stands for Time in years.
This gives us the following formula
for calculating simple interest:
I =PxRxT
Problem:
A contractor borrows $750.00 from a
money lender for two years and seven
months. The money lender is charging
8% interest. How much money will the
contractor have to repay?
Procedure:
1. The time period is 31 months, at
30 days to a month for 12 months.
2. Substitute values into formula:
I = $750 x 8% x 31
12
3. Solve for I (Interest) by cancellation:
I = 750 x 8 x 31
100 x 12
Calculating Simple Interest
Discussion: Interest is money that
is paid for the use of money, and as
a contractor or builder, one needs to
know how it works.
I = $155.00 total interest to be
paid.
Answer: The contractor will pay back
a total of $905.00, which is the
original principal of $750 plus the
$155 in interest.
CHAPTERVI
BASIC SKILLS AND OCCDPATIONAL PROFILES
INTRODUCTION
The main objectives of the Kiteredde Construction Institute are to train
young men in the techniques of construction, to place them in jobs in the construction industry and in public works assignments, and to train them in basic
business and management skills to enable them to create and operate small contracting firms successfully.
The preceding chapter outlines some of the management components which are
covered in course work for those trainees interested in forming small construction firms. In addition to course work, trainees are given practical experience in the field through working with small construction firms and enterprises
managed by the Bannakaroli Brothers and the Kiteredde Construction Institute.
These firms are comprised of trainees, recent graduates who are known as “Old
Boys”, and more experienced construction professionals who have worked with the
Bannakaroli Brothers for a number of years. In addition, selected graduates
of the program are brought back on contract as graduate assistants to manage
or assist with specific building or training projects, which gives them
further opportunities to enlarge their skills.
This chapter deals with the standard occupational and skill profiles which
the Kiteredde Construction Institute adopted from the IL0 as a base-line for
skills measurement in 1980. These profiles serve as a performance-based set of
criteria for the assessment of actual technical competencies, and supplement
the basic vocational/technical training criteria established by appropriate
Ugandan and East African education authorities.
The specific skills and profiles listed here provide a practical check-list
for vocational trainers, institutions, trainees, graduates and construction
supervisors. They are included in this manual primarily as a set of guidelines
for KC1 trainees, graduates and others, as an aid to continued learning and to
encourage the continual upgrading of technical skills.
Occupational Profiles
Occupational profiles are listings of tasks and performance levels to be
attained by trainees during the course of their studies at the Kiteredde Construction Institute. Under each course title is a series of code numbers and
titles which refer to occupations as defined in the International Standard
Classification of Occupations (ILO, Second Edition, Geneve, Switzerland, 1968).
The purpose of this reference is to indicate the occupations for which
graduates of KCI’s training programs would qualify as a result of the training
received. Thus, the profiles serve as an important source of information to
candidates for admission to the school, to their parents and to other advisors
helping candidates with their plans for entering vocational training. At the
time of graduation, students have a realistic idea of the occupations for
which they are qualified, and prospective employers have an indicator by which
to measure the suitability of the graduate for specific positions.
91
The profiles list tasks which are either (a, common to several
different
occupations, or (b) related only to one occupation. Alongside
each task is a
performance level which is attained as a measure of the trainee's
success
in
meeting the performance objectives of the training program.
The tasks listed are built into the learning sequences of the training
program, so that the skills, knowledge and attitudes which are required for
successful performance are tested out and mastered in a logical
and progressive
around
sequence. The learning objectives for each course element are built
the detailed skills and performance criteria, and these detailed objectives
provide the indicators for evaluating learning achievement. Evaluation is a
measure of trainee performance of occupational tasks under the conditions
described, and up to the levels indicated. Graduation from the Kiteredde Institute indicates that the trainee has met the standards of performance
established by KC1 in consultation with the appropriate vocational
and technical
training authorities of the Ministry of Education.
A certificate is attached to the graduate’s diploma detailing the proficiencies achieved, and this can be presented to prospective
employers
as
evidence of the graduate’s qualifications for employment.
The profiles are reviewed annually by the staff of the Kiteredde
Construction Instiutute, assisted by external evaluators, to examine the need
for refinement and modification both in terms of changing job markets and
and manpower needs, and to appropriately reflect changes in the curriculum.
KC1 began in 1980 wth a basic six month intensive training program followed
by
job placements. Over the past few years the program has been extended,
first
to nine months to conform to certification requirements of the Ministry of Education, and more recently has been extended to two years. In the current
model, trainees receive nine months of instruction at KCI, and then devote
more than a full year to practical on-the-job training in the construction
industry, before returning to KC1 for advanced coarse work prior to graduation. Trainees are evaluated during the working internship portion of the
program by their employers and supervisors, and through follow-up visits by
KC1 staff.
Presently the Kiteredde Construction Institute offers
course work and
practical skills training in Masonry, Drafting, and Carpentry. The demand for
Cabinet-Making from the nearby rural and small urban areas has led to planing for additional course work, equipment and facilities to establish a
Cabinet-Making (Carpentry-Joinery) component to fulfill these expressed needs.
At the present time, trainees are admitted to all of the instructional areas,
rather than specializing in one, the purpose being to give each graduate a
firm grounding in a range of skills and to enhance his employability through
versatility. The small business management course is provided for promising
trainees and graduates with specific aptitude for and interest in forming contracting firms.
92
Performance Standard Key
A.
Ability to perform the task
B.
Ability
c.
Ability to identify the need for the performance
to execute it.
D.
Ability to instruct others
to
perform the task
under
direct
upon
receiving
in
the
supervision.
a work order.
performance
of
of
a task
and ability
a task.
Hasonry
A student completing training under
qualified to apply for a position under
titles:
g-51.20
g-51.40
g-51.50
g-52.30
g-52.40
g-55.10
this profile
any one of
will
be eligible
and
the following
occupational
Bricklayer (Construction)
Stonemason (General)
Tile Setter
Reinforcing Iron Worker
Cement Finisher
Plasterer (General)
General Occupational Description:
Lays bricks, hollow tiles and similar
building
blocks
to construct
walls,
partitions, arches, interior fireplaces and chimneys and other structures.
Builds stone work such .s walls, piers and abutments;
lays walks and consets tiles
to surface
walls and floors.
structs other types o stonemasonry;
surfaces
of concrete
Forms and pours reinforced concrete structures. Finishes
structures. Applies one or more coats of plaster
to walls
and ceilings
of
buildings to produce a finished surface.
Task Listings
1.
Examines plans and other specifications
of structure to be erected.
2.
Spreads mortar with trowel on building blocks
and lays them in rows, designs and shapes.
3.
Taps block with trowel to align it and to
embed it firmly in mortar.
4.
Checks vertical and horizontal alignment of
structure With level and plumb-line as work
progresse6. (May fix brick or terra cotta
veneer to face of masonry structure, form
ornamental brickwork designs, and alter and
repair existing brickwork).
Performance
Standards
A
c
B
D
Masonry Task Listings (continued)
Performance Standards
A
5.
r
0.
Selects cut stone and shapes it preparatory
to setting with chisel, hammer or other
shaping tools.
Spreads mortar with trowel over foundation
cr laid stone.
7.
Sets stone in mortar bed by hand or with
lifting device, and tamps into place with
hammer.
8.
Pills vertical joints between stones
with mortar and finishes them with pointing trowel. (May specialize in a particular
type of stonemaaonry and be designated
accordingly. May fix stone facing to
structure of brick or concrete).
9
1 a
Can plan and lay out on paper the materials
lists, time and labor schedules, and costs,
for all of the above.
10. Calculates numbers of different tiles
required.
11. Soaks tiles in water to prepare them
for setting.
12. Applies plaster coat and layer of
mortar to wall and sets tiles according to pattern.
13. Cuts tiles at corners and edges to
somplete surface to be tiled.
14. Taps tiles into place or slides
leveling board over their surfaces,
tapping them with board to level
surface and to increase bond between
tiles and cement.
15. Aligrs rows of tiles, using spirit level
and straight edge.
LG, Wipes newly laid tile surfaces with filling
materials to fill joints, and cleans surfaces.
17. Assembles or constructs shuttering, and fixes
it in position.
94
B
C
D
Masonry Task Listings (continued)
Performance Srtandards
A
18. Cuts, shapes, assembles and fixes
reinforcing rods or mesh in shuttering.
19. Prepares concrete by hand or in a concrete mixer, or signals to helper to
deliver ready-mixed concrete.
20. Pours concrete into shuttering, distributing it, tamping it or settling it.
21. Levels and smooths surface of concrete.
22. Removes shuttaring when concrete is dry,
and smooths rough edges.
23. Cuts ridges, bumps and projecting wire
from concrete surface with chisel and
hammer,
24. Patches holes and broken corners by
wetting them, spreading cement mortar
into them, and smoothing surface with
trowel or float.
25. Removes
surface
mixture
rubbing
blemishes and uneven parts of
by wetting OX applying liquid
of sand, cement and water, and
with abrasive block.
26. Finishes surface by &;ing
with damp brush.
27. Smooths and shapes curface of freF!lly
poured concrete with straight edge and
float for fine fini,qh.and with edging
tool to shape corners.
28. Applies first coat of plaster to surfuce
with trowel; levels and smooths it.
29. Scratches surface to provide bond for
finish coat, and shapes plaster border
along sides of surface to provide guT6e
for finish coet.
30. Spreads finish coat between borders,
leveling it with rod, and smoothing
it with trowel; finishes corners and
angles with angle float.
B
C
D
Masonry Task Listiq
-
(continued)
31. Calriea out interior ornamental
plastering, and plafters outside
surfaces of buildings.
32. Cleans tools and repairs them when
necessary.
96
Pmformmce
Standard
-
A
C
B
D
Carpentry
A student completing training under this profile will be eligible and
qualified to apply for a position under any one of the following occupational
titles:
9-54.10
9-54.20
9-54.20
9-54.70
Carpenter (General)
Construction Joiner
Concrete Shutter
Bench Carpenter
General Occupational Description:
Cuts out, assembles, erects and repairs structural and other woodwork at
workbench and on construction site. Assembles and installs wooden frameworks
of buildings, flooring and other heavy-framed woodwork, such as pouring chutes
and scaffolding at building sites. Builds, assembles, places in position and
dismantles rough wooden structurr (shuttering), Fits, assembles and installs
wooden internal and external fixtures of buildings such as doors and window
frames, facing and panelling. Cuts out, shapes, fits
and assembles
wooden
mainly
at
the
workbench,
both
for
making
new
articles
and
repair!ng
parts,
used ones.
Carpentry
Task Listing
Performance Standards
A
1.
Works from plans, sketches or from
instructions received.
2.
Selects wood and other materials to
be used.
3,
Marks out reference points according
to pattern or plan to facilitate cutting and shaping.
4.
Cuts and shapes wood by hand or machine
tools, performing such operations as
sawing, grooving, planing and sanding.
5.
Assembles wooden parts using glue, screws
nails and other means.
6.
Erects and repairs prepared work pieces
such as rafters, wooden floors, partitions,
windows, door frames, and staircases.
7.
Maintains and sharpens own tools.
8,
Performs related tasks in conjunction
with other trades.
B
C
D
97
Carpentry Task Listing (continued)
Performance Standards
A
9.
Makes concrete shuttering.
10. Marks out, cuts and adjusts wood to
be assembled in shuttering partitions,
or assembles shuttering from prefabricated wooden parts.
11. Assembles shuttering parts on site and
screws, nails, or clamps them together.
12. Plans and iays out on paper all materials
lists, time and labor schedules, and costs
for all of the above.
13. Places stays between shuttering partitions
to give structure necessary rigidity.
14, Aligns shattering with bob and plumb-line.
15. Patches holes in shuttering.
16. Dismantles shattering when concrete has
set ,zndcleans off adhering concrete.
17. Fitting, assembling, installing and repairing of wooden facing, panel fixtures,
and fittings in woodwork or on site. (May
assemble sections from ready-cut pieces,
and may specialize in particular product
and be designated accordingly).
98
B
-C
D
Cabinetmaking
A student completying training under thi; $tofile will be eligible and
qualified to apply for a position under the following occupational title:
8-11.20 Cabinetmaker
General Position Description:
Makes completely and repairs wooden articles such as cabinets and furnlture, using hand tools and woodworking machines.
Cabinet-Making Task Listing
1.
Studies irawinge of articles to be made
and marks off outline of parts on wood.
2.
Shapes parts by operations such as cutting,
planing and turning.
3.
Trims joints to make them fit together
snugly.
4.
Glues joints, fits parts together, and
clamps them until glue is dry.
5.
Drives nails, dowels or screws through
joints ts reinforce them.
6.
Fit sub-assemblies and other parts
together to form completed unit.
7.
Finishes articles, attaches trim,
applies veneer, stain or polish, and
installs hardware such as hinges and
drawer pulls.
8.
Repairs and refashions high-grade
articles of furniture.
9.
Fits, assembles and repairs wooden
facing, panels, fixtures and fittings
in woodwork on site.
Perfomance
--.--
Standards
A
C
B
D
10. Plans and lays out on paper all materials
lists, time and labor schedules, and
costs for all of the above.
99
Drafting
At the present time the Kiteredde Construction Institute is not providing
the level of training in this skill area to qualify its graduates under the
usual occupational titles of:
o-32.40 Civil Engineering Draftsman
o-32.50 Architectural Draftsman
The level of drafting skills being provided enables the students to make
basic drawings for the construction of houses, sheds, agricultural buildings
and other structures. The students are able to read plans, follow them, and
learn to draw to scale.
General Occu_pationalDescription:
Prepares working plans and drawings for construction based on designers
sketches and specifications, and prepares charts and working drawings for
other purposes. Prepares drawings for the construction of houses, school
buildings, farm buildings and other basic structures.
Draftlug - Task Listiq
Performance Standards
A
1
A .
Prepares work plans and drawings for
simple buildings based on designer's
specifications.
2.
Reads blueprints and translates these
into working plans.
3.
Calculates dimensions, angles, beam
strengths, truss strengths, walls
and carrying walls and factors them
into building design and drawings.
4.
Makes blueprints and drawings of
designed buildings and building
site based on designer's specifications.
100
B
C
D
APPENDIX I
GLOSSARY OF TERM
Adobe :
A sun-dried block of mud, and a binder.
Air-dried:
The conditio:lof lumber (usually 12 to 20% moistur.
content) reached by exposing it for A sufficient period
to the prevailing atmospheric conditions.
Air drying:
The process of drying green lumber to expose it to prevailing at:nosphericconditions.
Banana Juice
(for paint):
By squelzzingor boiling down ripe bananas and &terns,the
juice can be used as an adhesive binding agent to put
together traditional local paints.
Bearing Walls:
Outside walls of a building bearing the weight and
stress of the roof structure.
Binder:
Adhesive characteristic of an element used to bond
dissimilar materials.
Bond :
Anything that binds, ties or fastens building materials
together chemically or mechanically.
Block:
A moulded rectangular rectangular prism larger than a
brick; typically adobe oz concrete.
Brick:
A moulded rectangular block of clay, baked until hard,
or sun dried for use in construction.
Casehardening:
A condition of stress and set in dry wood in which the
outer fibers are under compressive stress and the inner
fibers under (rensilestress, the stresses persisting
when the wood is uniformly dry.
Cell :
In wood anatomy, a general term for the minute units of
wood structure having distinct cell walls and cell
cavities. Includes wood fibers, vessel segments and
other elements of diverse structure and function.
Cement :
A construction adhesive , powdered, calcined rock and
clay materials that form a paste with water and set as a
solid mass.
Check :
Synonyms : Cracks, drying check, checking. A separatiou
of the wood fibers within or on a log, timber, lumber or
other wood product resulting from tension stresses set
up during drying, usually the early stages of drying.
103
C lay:
A fine-grained firm natural mdterial, plastic when wet.
A)
B)
Cl
Ant-hill clay.
River Bank clay.
Swamp clay.
Coffee husks:
By-products of coffee used (when dried) for starting
kiln fires and for crop fertilization.
Concrete :
A construction material consisting of gravel, pebbles,
broken stone or slag in a mortar or cement matrix.
Conditioning, a!r: In drying wood the movement of air by either natural or
mechanical means.
Forced circulation:
mechanical means.
The movement of air by
Country Kiln:
A basic brick or block kiln used in the countryside, not
permanent.
Damp Proof
Course :
Moisture barrier substructure, typtcally a richer mixture of mort.ar.
Decay:
Rot, or the decomposition of wood substance by
Advanced (or typical) de?z:
The older stage of
decay in which the destruction is readily
recognized because the wood has become punky, soft
and spongy, stringy, pitted or crumbly. Decided
discoloration or bleaching of the rotted wood is
often apparent.
Incipient decay: The early stage of decay which has
not proceeded far enough to soften or otherwise
perceptibly impair the hardness of the wood. It
is usually accompanied by a slight discoloration
or bleaching of the wood.
Defect:
Any irregularity or imperfection in a tree, log, or
lumber which reduces its volume or quality or lowers its
durability, strength, to utility value. Defects may
result from knots and other growth conditions and
abnormalities; from insect or fungus attack; from
milling, drying, machining or other processing
procedures.
Degrade :
A loss in adjudged quality which drops lumber to a lower
commercial grade.
104
Density:
The weight of a body per unit volume, usually expressed
in pounds per cubic foot or grams per cubic centimeter.
In wood, density changes in terms of moisture content.
Dipping :
Process of submerging lumber in a vat containing
fungicides or other chemicals, or used engine oil, to
prevent stain or decay, to impart water repellency,
and protect from termites, or to color the product.
Discoloration:
Synonym : Stain. Change in the color of lumber due to
fungal and chemical stains, weathering, or heat
treatment,
Drying of Timber:
Storage of processed timber. After several weeks,
moisture will evaporate from the timber.
Footings and
Foundation:
Substructure of a building or structure on firmest
possible soils to spread building weight over larger
area or down to soil bearing.
Frog:
Indentation in face of brick; brickmoulders mark.
Fungi :
Low forms of plants consisting mostly of microscopic
threads that traverse wood in all directions, converting
the wood to materials fungi use for their own growth.
Fungi cause decay and staining of lumber.
Grade :
A classification or designation of the quality of
manufactured pieces of wood, or of logs and trees.
Grain:
The direction, size, arrangement, appearance or quality
of the fibers in lumber. When used with qualifying
adjectives the term de:;lgnatesthe orientation of fibers
and/or growth rings in lumber.
Cross grain: Lumber in which the fibers deviate from
7
line parallel to the sides of the piece. Cross
grain may be either diagonal or spiral grain or a
combination of the two.
Diagonal grain: Lumber in which the annual rings are
at an angle with the axis of a piece as a result
of sawing at an angle with the bark of the log. A
form of cross grain.
Edge grain: Synonym : Comb grain, edge-sawn, quarter
grain, quarter-sawed, rift grain, rift sawed,
stripe grain, vertical grain. Lumber that has
been sawed or split so the wide surfaces extend
approximately at right angles to the rings,
exposing the radial surface.
105
End grain: The snds of wood pieces that are cut
perpendicular to the fiber direction.
-Flat grain: Synonym: Flatsawn, plain grain, plainsawed, slash grain, tangential cut. Lumber sawed
or split in a plane approximately perpendicular to
the radius of the log. Tumber is considered flatgrained when the annual growth rings make an angle
of less than 45 degrees with the surface of the
piece.
Straight grain: Lumber in which the fibers and other
longitudinal elements run parallel to the axis of
a piece.
Green lumber:
In general, lumber just cut from freshly felled trees.
In accordance with the American Softwood Lumber
Standard, lumber above 19 percent moisture content.
Grout:
Thin concrete mixture used to fill voids, such as the
interior of concrete blocks.
Hardwoods:
Generally one of the botanical groups of trees that have
broad leaves, in contrast to the conifers 31:softwoods.
(The term has no reference to the actual hardness of the
wood.)
Header:
Top framing member over a window or door opening.
Heartwood:
The inner layers of wood in the growing trees that have!
ceased to contain living cells and in which the reserve
materials, e.g., starch, have been removed or converted
into resinous substances. It is generally darker in
color than sapwood, though the two are not always
clearly differentiated.
Hoe!Gimbe:
A tool with a flat blade and a long handle used for
weeding, cultivating and breaking up the soil.
Impurities
(in clays):
Small stones, grass and other natural materials naturally mixed in pure clay.
Jamb:
Side and top members of window or door frame.
Joint:
A point or position at which two or more things aze
joined.
Joist:
Floor framing member for wooden floor. A horizontal beam
set from wall to wall to support the boards of a floor
or a ceiling,
106
Karai:
A basin used in East Africa for construction purposes,
16" wide by 5" in height. Volume equals 4.5 US Gallons
or 10 liters.
Lintel:
The horizontal beam over the top of a door or window.
Level:
A flat horizontal surface or plane at right angles to
the plumb or vertical angle.
Lime:
Calcfum oxide used as an adhesive or binding agent in
mortar mixes.
Lime Mortar:
Binding agent for brickwork.
Limestone:
A shaly or sandy sedimentary rock composed chiefly of
calcium carbonate.
Load:
A supported weight or mass.
Mabati/
Metal sheets/
Roof Iron:
Standard metal sheets of various thicknesses and sizes
made of galvanized iron or aluminum for roofing.
Moisture content
of wood:
Weight of the water contained in the wood, expressed as
a percentage of the weight of the oven-dry wood.
Average moisture content: The percentage moisture
content of a single sample of wood which is
representative of a larger piece.
Core moisture content: The moisture content of the
inner portion of a moisture coi*i:ent
section which
remains after a shell one-fourth the thickness of
the section has been removed.
Determination of moisture content: The testing of
lumber to determine the amount of moisture
present. This is usually expressed in terms of
percent of the oven-dry weight.
Final moisture content: The average moisture content
of the wood at the end of the drying process.
Green moisture content:
in a living tree.
The moisture content of wood
Initial moisture content: The moisture content of
the wood at the start of kiln-drying or airdrying,
Mortar:
A mixture of cement or lime with sand and water ured in
brick and block laying.
107
Mou'd:
Standard hand held wooden frame of various sizes used
for moulding bricks and blocks.
Moulder:
.2person who physically uses the mould to make bricks
and blocks.
Mudsill:
Rot-resistant wood member attached to a concrete foundation wall. Floor joists rest on top of it.
Nail:
A slim pointed piece of metal, often with a head, hammered into wood or other material as a fastener.
Non-bearing C;all: Inside wall of a structure not bearing any weight or
stress from the roof.
On-center:
Equal spacing of constructive elements, i.e., every 2”
apart, or every 2" on center.
Papyrus:
A tall grasslike water plant of Africa used for/In
roofing material, and for wall structure in m;idand
wattle construction,
Parquet Flooring:
Wood, often of contrasting colors, worked into an inlaid
pattern.
Piles:
Heavy beams driven into the earth as a support for a
structure.
Plasticity:
Quality of or capacity of being shaped tirformed. A
material such as wet clay, which can be made into a
variety of shapes by applying pressure, is characterized
by plasticity.
Plate:
Top or bottom horizontal frame member of stud wall.
Plumb:
A weight suspended from the end of a line used to
determine true vertical.
Posts:
Stakes, set upright in the ground to serve as markers or
structural supports.
Pozzolanas:
Binding agent associated with cement, llr;,o.
Purlins:
Secondary members placed on top of rafters, providing
strength and area for nailing on roofing materials.
Rafter:
A sloping beam that supports a roof.
Rammer or Tamp:
A tool with a handle and wide head, 6" - 24" cubic
inches, used for tamping/compressing soil.
Rebar:
Metal bar used in reinforcing concrete structures.
Reinforcing bar.
108
Pe-infarced
concrete:
Concrete strengthened with steel bars or rods.
Rice Husks:
Harvest.edrice waste, used to fire brick, and used as a
masonry filler.
Ridge :
The line fnrmed by the junction of two sloping surfaces.
Ring beam:
A horizontal beam at the r !;lgaof a II~.Lto which the
upper ends of the rafters Bre atiachcd.
Riser:
-The vertical part of a stair’s step.
Run:
Horizontal element of a slope.
Sapwood :
The outer layers of the stem that in the living tree
contain living cells and reserve materials. The sapwood
is generally lighter in color than heartwood.
Screed :
Grade level forms set at desired height so concrete ca.n
be roughly developed by dragging a straight edge over
the surface.
Set:
Fix, to put into a stable position or fixed position.
Sheathing:
Various coverings or structures resembling a sheath.
Shrinkage:
The contraction of wood fibers caused by drying below
the fiber saturation point. Shrinkage is usually
expressed as a percentage of the dimension of the wood
when green.
Slope:
An inclined line, surface, plane or stretch of ground.
Softwoods:
Generally one of the botanical groups of trees that, in
most cases, have needlelike to scalelike leaves; the
conifers. (The term has no reference to the actual
hardness of the wood.)
Straight Edge:
A rigid object (metal or wood) with a straight edge for
testing or drawing straight lines.
Stress, drying:
An internal force exerted by either of two adjacent
parts of a piece of wood upon the other during drying
caused by uneven drying and shrinking and influenced by
set.
Compressive stress: The stress that develops in the
interior region of wood during the early stages of
drying, caused by the shrinking of the outer
shell; also the stress in the outer layer at a
later point in drying caused by the shrinking of
the interior.
109
Tensile stress: The stress that develops in the
outer layers of wood during the early stages of
drying when these layers are trying to shrink but
are restrained by the still-wet interior region.
Stringer:
Side member of stairway that supports risers and treads.
Stud:
Vertical structural member of wall in frame building.
Thatch:
Plant stalks (mostly grass) used for roofing.
Threshold:
Piece of material over which door swings.
Tread:
Horizontal board in stairway.
Trim (Interior,
Exterior):
To make neat or tidy by chipping or smoothing,
Trowel:
A flat-bladed hand tool used for shaping substances such
as cement or mortar.
Truss:
A wooden or metal framework used to support and brace a
roof.
Veneered wood:
A thin layer of material bonded to and used to cover a
surface (finished, glass).
Warp:
Distortion in lumber causing departure from its original
plane, usually developed during drying. Warp includes
cup, bow, crook, twist and kinks.
Water, bound:
Moisture that is bound by adsorption forces within the
cell wall; that is the water in wood below the fiber
saturation point.
Free water: Moisture that is held in the cell
cavities of the wood.
Wood:
The tissues of the stem branches and roots of a woody
plant lying between the pith and cambium serving for
water conduction, mechanical strength and food storage.
Wood chips/
sawdust:
Pieces of wood or dust from sawing or harvesting of
timber that can be used to start kiln fires.
110
APPENDIX II
REFERENCES AND ACRMOULEDGEMENTS
1.
Building Construction, by H. K. Dancy, published by International Technology Publications, 1978.
2.
Clay Moulding Manual, The Secretary for Trade, Industry and Tourism, Box
30366, Lilongwe 3, Malawi, 1976.
3.
Lorena Owner-Built Stoves, Ianto Evans, Volunteers in Asia Publications,
1979.
I
4.
Designs for Rural Construction in Pakistan, 1978.
5.
Building Construction, W. B. McKay, Volume 3, 1975.
6.
Village Technology Handbook, Volunteers in Technical Assistance (VITA),
1970.
7.
Agricultural Handbook No. 531, U.S. Department of Agriculture Forest
Service.
8.
Agricultural Mathematics for Peace Corps Volunteers, Development and
Resources Corporation, 1968.
9.
Air Drying of Lumber: A Guide to Industry Practices, Agricultural Handbook No. 402, U.S. Department of Agriculture.
10.
Daniel A. Adam, Architect, Alberta, Canada.
illustrations.
11.
Bannakaroli Brothers, Kiteredde, Uganda, Brother Leandro, Superior
General. Brother Borgia, Headmaster, Kiteredde Construction Institute.
Brother Cosma, Farm Planner and local building materials expert,
Kiteredde Construction Institute. Brother Constanso, Instructor,
Kiteredde Construction Institute. Brother Mpuga, Building Supervisor,
Nnaluddugavu Construction Industry, Kyotera. Brother Emiliano.
12.
Vincent B. Kayabula, Graduate of Kiteredde Construction Institute,
Group II (1982). Art work and drawings.
13.
Sigurd Hanson, East Africa Regional Representative, The Experiment in
International Living, and former Headmaster, Kiteredde Construction
Institute.
14.
Judith and Robert Rondeau, and Betsy Ballard, Design Graphics,
Brattleboro, Vermont, USA.
Artist and consultant for
15. Appropriate Building Materials, Swiss Center for Appropriate Technology,
(SKAT i/12),Varnbuelstrasse 14, CH-1900 St. Gallen, Switzerland.
16. Appropriate Technology Sourcebook, Vols. I and II, Volunteers in Asia,
Stanford, California, 1981.
111
The Kiteredde Construction Institute
The Kiteredde Construction Institute, Rakai District, Uganda, was founded
in 1980 by the Bannakaroli Brothers and The Experiment in International
Living, in a joint project made possible by initial funding from the United
States Agency for International Development. It was further assisted by generous assistance from the Canadian International Development Agency, the
Australian High Commission, Catholic Relief Services, and CODEL.
The primary purpose of KC1 is to train young men for skilled employment
in the construction industry, through both thoretical and practical training,
to teach them building techniques using locally available materials, and to
place graduates in jobs in the construction industry. In addition, students
and graduates are given opportunities to learn the skills of small business
management to enable them to form small construction firms and to manage them
successfully.
In addition to training in the construction of houses, public and commetcial buildings and other structures, KC1 students are given practical experience in agricultural construction, including animal shelters, food storage
facilities, water systems and wells, and other rural applications.
The faculty and students have built their own classrooms, dormitories and
other facilities out of local materials. They have worked together to open
up new farm acreage annually, and to rebuild the poultry flock and cattle
herd in an effort to make the institution as nearly self-sufficient as possible in producing its own food supplies.
In its fifth year of operation, KC1 is now concentrating on continuing to
upgrade the quality of training and the working internships it provides for
its students and graduates, and is strengthening its capacity to carry out
an increasing volume of extension and outreach training for other technical
schools and other communities in Uganda. The purpose of this effort is to
share KCI's knowledge of clay-moulding, construction, training and the use
of local materials with others.
The Experiment in International Living
The Experiment in International Living CEIL), founded in 1932, is one of
the oldest and largest international educational exchange organizations in
the world. It is a registered private voluntary organization, carrying out
technical assistance, education and training projects, and refugee assistance
programs in Asia and Africa. EIL's School for International Training is an
accredited graduate and undergraduate college which specializes in preparing
individuals for careers in teaching, training, program management, intercultural communications, the management of human service agencies and public
and private organizations in the U.S. and abroad, and in international technical assistance.
Since 1979, EIL has participated fully in the design and development of
the curriculum, training programs and approaches to training at KCI, and continues to be actively involved in the work of this growing Ugandan vocational
training institution.
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