Building construction
-
Upload
jonah-scott -
Category
Documents
-
view
187 -
download
35
description
Transcript of Building construction
CONSTRUCTION 2010
i
MAKERERE UNIVERSITY
FACULTY OF TECHNOLOGY
DEPARTMENT OF CONSTRUCTION ECONOMICS
AND MANAGEMENT
PROGRAM: BSc CONSTRUCTION MANAGEMENT
ASSSIGNMENT: CONSTRUCTION MODULE REPORT
NAME: KALULE ISAAC
REGISTRATION No: 09/U/625
STUDENT No: 209000864
INSTRUCTOR: Mr. RWENDEIRE IVAN
CONSTRUCTION 2010
ii
DECLARATION
“I hereby declare that I have read this thesis and in my opinion this thesis is
Sufficient in terms of scope and quality.”
Signature: ……………………………………………….
Name of Supervisor:
CONSTRUCTION 2010
iii
“I declare that this practical report entitle “CONSTRUCTION” is the result of my
own research except as cited in the references.”
Signature: ……………………………
Name: KALULE ISAAC
CONSTRUCTION 2010
iv
ACKNOWLEDGEMENT
It is really a hard task for me to complete this study without the help from those
people around me.
I would like to express my gratitude of thanks to Mr. Rwendeire Ivan who spent
time to guide and help us patiently on what should be included in this report. I
wouldn‟t never been able to get through this without your advice.
Besides, I would like to thank my parents and family for their support and
encouragement. It is meaningful and helpful to me. Lastly thank you to all my
friends who willing to help me and giving a full concern to me especially during
the discussions we together, thank you very much.
CONSTRUCTION 2010
v
TABLE OF CONTENTS
TITLE PAGE
TITLE PAGE i
DECLARATION ii & iii
ACKNOLEDGEMENT iv
TABLE OF CONTENT vi
1.1 Objectives 1
1.2 Introduction 1
1.2.1 Applications of construction 1
1.3 Building Construction 2
1.31 Principal factors of construction
1.4 Design process
1.41Building team
1.5 site works and setting out 6
1.5.1 Clearing site 6
1.5.2 Hoarding 6
1.5.3 Leveling 6
1.5.4 Setting out 7
1.6 Sub structure 9
1.61 Foundations 9
1.7 Super Structure 14
1.7.1 Walls 14
1.7.1.1 Walling materials 14
1.7.1.2 Block and brick bonding 14
1.7.2 Beams columns and slabs 15
1.7.2.4 False work and form work 16
1.7.3 Roofs 19
1.8 Scaffolds 24
1.9 Services 29
1.9.1 Drainage systems 29
1.9.1.1 Types of drainage systems 29
1.9.2 Septic tank 31
1.9.3 Stabilization ponds 32
2.0 Water supply 33
CONSTRUCTION 2010
vi
2.1Indirect water system 35
2.2 direct water supply 36
3.0 conclusion 38
References 38
CONSTRUCTION 2010
1
CONSTRUCTION
1.1 OBJECTIVES
To create an understanding of the basic component of a building,
documentation and materials quality and selection.
To explain the main components of a building structure, major sections,
elements and materials.
To understand the roles played by of the different parties involved in the
execution of a given construction projection.
1.2 Introduction
Construction is the process which involves assembling different structural
element in order to come with a stable structure backed up with the proper
planning, execution, and control of construction operations of a given projects .
1.2.1 Applications of construction
In civil engineering construction can be witnessed on a number of project
which among others include the following;
Highways/ roads/ bridges
Building construction
Dams
Railway lines
Retaining structures
Water resource engineering facilities
Airport runways/ air fields
Recreation facilities
1.3 BUILDING CONSTRUCTION
Building construction is a process which involves enclosing space (hoarding)
where construction of a given structure is going to be executed, in order to
create a favourable internal working environment, assembling both structural
and architectural elements while following the relevant documents (structural
CONSTRUCTION 2010
2
drawings, architectural drawings etc) and sustaining the structure throughout
its working life time by regular maintenance.
1.3.1 PRINCIPAL FACTORS OF BUILDING CONSTRUCTION
Capital
This is measure of the accumulated financial strength of an individual, firm,
or nation, created by sacrificing present consumption in favor of investment
to generate future returns above investment costs. Capital plays different
roles in the execution of the proposed project which among others include
the following; payment for both structural element (like reinforcing steel
bars, aggregates, cement etc) and architectural element (like tiles, fitting,
paint etc), payment for service offered by the different parties (like
engineers, surveyors, casual labourers etc) involved in the execution of the
proposed project
Land
Land refers to the space or ground on which the proposed project is to be
executed whose ownership is clearly shown by legal document like land
titles.
In Uganda there are mainly four categories of land ownership viz;
i) Customary land
Customary land is land which is owned by indigenous communities
and administered in accordance with their customs, as opposed to
statutory tenure usually introduced during the colonial periods.
Common ownership is one form of customary land ownership.
ii) Leasehold land
This is land which is owned by the government or a landowner and
then leased to a tenant for a fixed period of time.
iii) Milo land
This is form tenure where land ownership is in the hands of tribal or
clan leaders and under this category land is administered by the local
land boards.
iv) Freehold land
Here ownership is in perpetuity, and a certificate of title is issued.
CONSTRUCTION 2010
3
Labour
This refers to human. Labour may either be skilled (this constitutes technical
effort forwarded towards the execution of the proposed project by engineers,
quantity surveyors, land surveyors, etc) and unskilled (this constitutes casual
and physical effort forwarded towards the execution of the proposed project
mainly by foremen, clerks of works, porters etc)
Other factors which affect building construction among others include:
Intended purpose of the proposed building, material availability, topography,
available infrastructure, security, space etc.
1.4 DESIGN PROCESS
The design process includes the active and continuing participation of users, code
officials, building technologists, cost consultants, civil engineers, mechanical and
electrical engineers, structural engineers, specifications specialists, and consultants
from many specialized fields. The illustration in figure 1below shows a simplified
layout of the design process:
Figure 1 (adapted from: /www.mfe.govt.nz/publications/sus-dev/integrated-whole-
building-design-guidelines/html/images/figure1.gif)
CONSTRUCTION 2010
4
Preparation for the project can be led by many players but generally comes
from the user/client who identifies the need for building on the basis of
quantifiable requirements for space and budgetary capacity to undertake the
activity. A needs assessment often accompanies this planning activity—it
can describe existing space use; develop realistic estimates of requirements,
both spatial and technical; and arrive at a space program around which
Once the Pre-design activities are complete, the architect or other prime
consultant, in consultation with his or her team of sub-consultants, may
produce initial graphic suggestions for the project or portions of it. Such
suggestions are meant to stimulate thought and discussion, not necessarily to
describe the final outcome.
Gradually a design emerges which embodies the interests and requirements
of all participants while also meeting the overall area requirements which the
project budget will have established during Pre-Design activities. The
resulting Schematic Designs produced at this stage show site location and
organization, general building shape, space allocation, and an outline
specification which makes an initial list of components and systems to be
designed and/or specified for the final result.
It is often useful to have a cost estimate performed by a professional cost
estimator called a quantity surveyor at this point. Cost estimations is done by
preparation of a bill of quantities. They are prepared by a “taking off”
process in which the cost of a building or other structure is estimated from
measurements in the architect's drawings. These are used to create a cost
estimate such as in regard to the square area in meters of walls and roofs, the
numbers of doors and windows, and systems as heating, plumbing and
electrics. An example of a bill of quantity is as illustrated in figure 2 :
The approved definitive design documents are developed into
comprehensive construction drawings and specifications that are submitted
to the concerned authorities for endorsement or approval of the proposed
project. The approval is effected by issuing of a building permit.
After approval, a cost estimate (bill of quantities) can be used for the
selection process of the building company or contractor a process known as
tendering or bidding. Tendering may either be open or restricted
CONSTRUCTION 2010
5
i) Open tendering: Bidding process that is open to all qualified bidders and
where the sealed bids are opened usually in public for scrutiny and are
chosen on the basis of price and quality. Also called competitive tender or
public tender.
ii) Restricted tendering or bidding: Invitation to bid (ITB) sent only to
selected contractors who have been pre-qualified through a screening
process.
After the general contractor is selected construction commences and it is
done with the whole of building team collectively participating.
Figure 2 (adapted from; www.ajk.ie/pages/products/images/clip_image006.jpg)
CONSTRUCTION 2010
6
1.4.1 THE BUILDING TEAM
Building is essentially a team effort in which each member has an important role to
play. Figure 3 shows the organization structure of a typical team;
BUILDING OWNER
ARCHITECT
CONTRACTOR CLERKS OF WORKS QUANTITY SURVEYOR
CONSTRUCTION MANAGERS SURVEYORS ESTIMATORS BUYER ADMINISTRATOR ENGINEERS SITE AGENT
GENERAL FOREMAN COSTING
TRADES FOREMAN ACCOUNTING
OPERATIIVES OFFICE STAFF
Figure 3
1.5 SITE WORKS AND SETTING OUT
When the site has been taken over, the task of preparing for and setting out the
building can be commenced. These operations can be grouped under four
categories viz:
1. Clearing site
2. Hoarding site
3. Establishing levels
4. Setting out the building
CONSTRUCTION 2010
7
1.5.1 Clearing site
This may involve demolition of existing buildings, the grubbing out of bushes
and trees or existing tree stumps and removal of soil to reduced levels.
1.5.2 Hoarding
Hording involves enclosing the site using iron sheets of inferior gauge or
fencing using wire mesh. The law requires that building sites should be hoarded
before construction commences. The hoarding needs to be accurately
constructed in order to provide protection to the public, resist impact damages,
resistance anticipated by wind pressure and adequately lit at night.
Figure 4 shows the typical hoarding details.
1.5.3 Leveling
Levels can be established using the following methods;
1. Cut and fill
2. Cut
3. Fill
CONSTRUCTION 2010
8
Figure 4 (adapted from construction technology handbook by R. chudley an R. Greeno 5th
edition page 86)
1.5.4 Setting out
This task is usually undertaken once the site has been hoarded, cleared of any
debris or obstruction and any reduced level excavation works are finished.
Accurate setting out is of paramount importance and should therefore only be
carried out by competent persons and all their work thoroughly checked. This
involves setting out the building outline followed by setting out trenches
1.5.4.1 Setting out the building outline
The first task in setting out a building out line is to establish a baseline to
which all the setting out can be related. Usually the longest side of the
building is chosen for convenience. Figure 5 illustrates this.
CONSTRUCTION 2010
9
Figure 5 (adapted from construction technology handbook by R. chudley 8th
edition page111)
1.5.4.2 Setting out trenches
The objectives of this task are:
To establish the excavation size, shape and direction and
To establish the width and position of the wall.
The outlines of the building will have been set out and using this out line,
profile boards can be setup to control the position, width and possible depth
of the proposed trenches. Profile boards should be set up at least
2.000metres clear of the trench position so as not to obstruct the excavation
work. Figure 6 illustrates this.
CONSTRUCTION 2010
10
Figure 6 (adapted from construction technology handbook by R. chudley 8th
edition page112)
1.6 SUB-STRCTURE: FOUNDATIONS
Sub structure is the portion or part of the building below the ground level. It
normally includes foundations and the ground floor slab. The purpose of the
sub structure is to firmly anchor the building to the ground, transfer and
distribute all the loading to the ground.
1.6.1 FOUNDATIONS
The function of any foundation is to safely sustain and transmit to the
ground on which it rests the combined dead, imposed and wind loads in such
a manner so as not to cause settlement or other movements which may
impair the stability and/ or damage to any part of the building.
CONSTRUCTION 2010
11
1.6.1.1 FOUNDATION TYPES
There are four types of foundation types namely: strip, pad, raft, and pile. These
foundation types are either used individually or in combination on a building
project.
STRIP FOUNDATION
This type involves construction of a plinth wall on mass concrete along the
trenches. The trenches are normally dug where actual walls of the super structure
are erected. The details of strip foundations are shown in figure 7.
Application
These are more suitable for most subsoils and light structural loading such as those
encountered in low to medium rise domestic dwellings where mass concrete can be
used.
Figure 7 (adapted from construction technology handbook by R. chudley an R. Greeno 6th
edition page 208)
PAD FOUNDATION
CONSTRUCTION 2010
12
These are foundations with reinforced concrete bases and columns. The columns
are usually rectangular or circular in shape. Pad foundations are either combined
(with one column fixed on one base) or combined (with more than one column
fixed on one base) Figure 8 gives details of both isolated and combined pad
foundation
Application
Pad foundations a usually applicable in storied building where the structure is
susceptible to heavy loads.
Figure 8 (Adapted from: building construction handbook 6th edition by R. Chudley an R. Greeno
page 191)
CONSTRUCTION 2010
13
PILE FOUNDATION
These can be defined as a series of columns constructed or inserted into the ground
to transmit the load(s) of a structure to a lower level of subsoil.
Application
Piled foundations can be used when suitable foundation conditions are not present
at or near ground level making the use of deep traditional foundations uneconomic.
The lack of suitable foundation conditions may be caused by:-
1. Natural low bearing capacity of subsoil.
2. High water table giving rise to high permanent dewatering costs.
3. Presence of layers of highly compressible subsoils such as peat and recently
placed filling materials which have not sufficiently consolidated.
4. Subsoils which may be subject to moisture movement or plastic
Classification of foundations
Pile foundations can either be friction or end bearing depending on the way they
transmit the loads to the sub soil. Figure 9 show detailed information of both
friction and end bearing foundations.
Figure 9 (Adapted from: building construction handbook 6th edition by R. Chudley an R. Greeno
page 205)
RAFT FOUNDATION
These are used to spread the load of the superstructure over a large base to reduce
the load per unit area being imposed on the ground. Figure 9 illustrates typical
details of a raft foundation.
CONSTRUCTION 2010
14
Figure 9 (Adapted from: building construction handbook 6th edition by R. Chudley an R. Greeno
page 203)
Application
This is particularly applicable where low bearing capacity soils are encountered
and where individual column loads are heavy.
CONSTRUCTION 2010
15
1.7 SUPER STRUCTURE
Sub structure is the portion or part of the building above the ground level. It
normally includes the walling, windows, doors, beams, slabs, columns, and the
roof.
1.7.1 WALLS
These are structures of bricks, stones, or blocks used to enclose (external walls),
divide (partition and party walls) or support a building. Walls can be constructed
from different materials and using different bonding for the case of brick and block
walls
1.7.1.1 WALLING MATERIALS
The different materials that can be used in the construction of a walling unit among
others include the following:
Bricks
Mortar
Concrete
Steel
Mud and wattle
Grass and wattle
Timber
Stones
1.7.1.2 BLOCK AND BRICK BONDING
Bonding refers to an arrangement of bricks or blocks in a wall, column or pier laid
to a set pattern to maintain an adequate lap.
Purposes of Brick Bonding
1. Obtain maximum strength whilst distributing the loads to be carried
throughout the wall, column or pier.
2. Ensure lateral stability and resistance to side thrusts.
3. Create an acceptable appearance.
FORMS OF BONDING
There are mainly four forms of brick bonding used in construction and these
include the following:
CONSTRUCTION 2010
15
Stretcher bond; this involves laying all courses of stretcher. Figure 10
illustrates this form of bonding.
Figure 10 (adapted from: /sites.google.com/site/building4today/_/rsrc/1267550154565/B4T-
Brick-Stretcher-custom-size-364-264.jpg)
Header; this involves laying all courses of header. Figure 11 illustrates this form
of bonding.
Figure 11 (Adapted from;
/sketchup.google.com/3dwarehouse/details?mid=be22f126cbf9071afb2ff900498c5c8d)
CONSTRUCTION 2010
16
English Bond; formed by laying alternate courses of stretchers and headers
it is one of the strongest bonds but it will require more facing bricks than
other bonds. Figure 12 illustrates this form of bonding.
Figure 12 (Adapted from:/sites.google.com/site/building4today/_/rsrc/1267550153936/B4T-
Brick-English-custom-size-406-307.jpg)
Flemish Bond; formed by laying headers and stretchers alternately in each
course. Not as strong as English bond but is considered to be aesthetically
superior uses less facing bricks. Figure 13 illustrates this form of bonding.
. Figure 13
CONSTRUCTION 2010
17
1.7.2 BEAMS, COLUMNS AND SLABS
1.7.2.1 BEAMS
These are horizontal load bearing members which are classified as either main
beams which transmit floor and secondary beam loads to the columns or secondary
beams which transmit floor loads to the main beams. Figure 14 illustrates typical
details of beam.
1.7.2.2 COLUMNS
These are the vertical load bearing members of the structural frame which
transmits the beam loads down to the foundations. They are usually constructed in
storey heights and therefore the reinforcement must be lapped to provide structural
continuity. Figure 15 illustrates typical details of column.
1.7.2.3 SLABS
Reinforced concrete slabs are mainly of two type namely hollow (which comprise
of maxpans commonly known as “kajjansi”) and solid (which are made from
concrete and reinforcements)
Figure 16 illustrates typical details of rectangular and square solid slab.
1.7.2.4 FORM AND FALSE WORKS
Concrete when first mixed is a fluid and therefore to form any concrete member
the wet concrete must be placed in a suitable mould to attain the desired shape, size
and position as it sets. These moulds are called formwork.
Formwork is supported by temporary structures known as falsework.
Falsework refers to temporary structures or elements used to support formwork in
order to hold the concrete components in place until it has sufficiently advanced to
support its self. Figures 17 and 18 illustrate typical details of a beam and column
formworks respectively.
1.7.3 FINISHES
Finishes include all final surfaces provided to roofs internal and external walls,
floors, stairs and ceilings to render the structure habitable as per the needs of the
client. The figure below illustrates details of tile floor finish
Common finishes include:
Plastering
CONSTRUCTION 2010
18
Painting
Tiling
Terrazzo
Asphalt or bitumen
CONSTRUCTION 2010
19
Figure 14 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 380)
CONSTRUCTION 2010
20
Figure 15 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 384)
CONSTRUCTION 2010
21
Figure 16 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 377)
Figure 17 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 395)
CONSTRUCTION 2010
22
Figure 18 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 396)
1.7.3 ROOF
Roofs can be classified as being either;
1. Flat: pitch from 0o to 10
o. Figure 19 below illustrates typical details of a flat
roof. or
2. Pitched: pitch over 10o. Pitched roofs can further be sub-divided into the
following forms
Lean to roofs
Monopitch roofs
Gamble end roofs
Hipped end roofs
Mansard or gambrel roofs
Figure 20 and 21 below illustrates typical details of these forms of pitched roofs. or
CONSTRUCTION 2010
23
Figure 19 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 435)
ROOF STRUCTURE
A roof is in a very exposed situation and must therefore be designed and
constructed in such a manner as to:-
1. Safely resist all imposed loadings such as snow and wind.
2. Be capable of accommodating thermal and moisture movements.
3. Be durable so as to give a satisfactory performance and reduce maintenance
to a minimum.
ROOF TRUSSES
These are triangulated plane roof frames designed to give clear spans between the
external supporting walls. They are usually prefabricated or partially prefabricated
off site and are fixed at 1800mm centres to support purlins which accept loads
from the infill rafters. Figure 22 below illustrates typical details of a roof truss.
CONSTRUCTION 2010
24
Figure 20 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 436)
CONSTRUCTION 2010
25
Figure 21 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 437)
ROOF COVERING MATERIALS
These among others include the following;
Iron sheets
Tiles
Slates
Timber
Grass
CONSTRUCTION 2010
26
Figure 22 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 441)
CONSTRUCTION 2010
27
1.8 SCAFFOLDS
These are temporary working platforms erected around the perimeter of a building
or structure to provide a safe working place at a convenient height. They are
usually required when the working height or level is 1500mm or more above the
ground level.
1.8.1 TYPES OF SCAFFOLDS
These include among others the following.
1. Putlog Scaffolds; these are scaffolds which have an outer row of standards
joined together by ledgers which in turn support the transverse putlogs
which are built into the bed joints or perpends as the work proceeds, they are
therefore only suitable for new work in bricks or blocks. Figure 23 shows
typical details of a putlog scaffold
2. Independent Scaffolds; these are scaffolds which have two rows of
standards each row joined together with ledgers which in turn support the
transverse transoms. The scaffold is erected clear of the existing or proposed
building but is tied to the building or structure at suitable intervals. Figure 24
shows typical details of an independent scaffold.
3. Mobile Scaffolds; otherwise known as mobile tower scaffolds. They can be
assembled from pre-formed framing components or from standard scaffold
tube and fittings. They can be easily transferred from on part of the building
to another due to presence of caster wheels at its bottom. Figure 25 shows
typical details of a mobile scaffold.
4. Truss-out Scaffold; this is a form of independent tied scaffold used where it
is impracticable, undesirable or uneconomic to build a scaffold from ground
level. The supporting scaffold structure is known as the truss-out Figure 26
shows typical details of a truss out scaffold.
CONSTRUCTION 2010
28
Figure 23 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 122)
CONSTRUCTION 2010
29
Figure 24 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 123)
CONSTRUCTION 2010
30
Figure 25 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 127)
CONSTRUCTION 2010
31
Figure 26 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 132)
CONSTRUCTION 2010
32
1.9 SERVICES
1.9.1 DRAINAGE SYSTEMS
Drains; these can be defined as a means of conveying surface water or foul water
below ground level.
Sewers; these have the same functions as drains but collect the discharge from a
number of drains and convey it to the final outfall.
1.9.1.1 TYPES OF DRAINGE SYSTEMS
There are main two types of drainage systems namely:
Combined and separate drainage systems.
1. SEPARATE DRAINAGE SYSTEM
This is the most common drainage system in use where the surface water discharge
is conveyed in separate drains and sewers to that of foul water discharges and
therefore receives no treatment before the final outfall. Figure 27 below illustrates
this type of drainage system.
Figure 27 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 132)
CONSTRUCTION 2010
33
2. COMBINED DRAINAGE SYSTEM
This is the simplest and least expensive system to design and all forms of discharge
are conveyed in the same sewer. Figure 28 below illustrates this type of drainage
system.
DISADVANTAGE
The whole effluent must be treated unless a sea outfall is used to discharge
the untreated effluent.
Figure 28 (adapted from construction technology handbook by R. chudley and R. Greeno 6th
edition page 661)
CONSTRUCTION 2010
34
1.9.2 SEPTIC TANKS
How it works?
The septic tank system work by separates wastewater to separate into layers. The
bacteria present in the tanks decomposes the solid wastes that have settled to the
bottom of the tank thereby transforming most of the wastes in solids and gases.
The outflow pipe in the tank drain out the access liquid in the drainage system. The
outflow, through a series of subsurface pipes is distributed throughout the drain
field. Here effluent undergoes final treatment as the soil absorbs and filters the
liquid whereas rest of the materials is broke down by the microbes. Figure 29
below illustrate the plan and section of a septic tank.
Figure 29 (adapted from google.com/images/septic tank)
CONSTRUCTION 2010
35
1.9.3 STABILIZATION PONDS
Categorization Of Stablisation Pond
Stablisation or stabilization pond can be categorized as follows;
Aerobic Ponds
An aerobic pond throughout its entire depth has varying concentration of oxygen.
Anaerobic Pond
Anaerobic pond is devoid of any oxygen except in the top at the air liquid
interface.
Facultative Pond
Facultative pond is a combination of both aerobic and anaerobic pond. That is, in
its top zone it is aerobic whereas it is anaerobic at its lower zone
The amount of oxygen present in the pond depends upon the following factors:
Temperature
Organic loading
Sunlight
Maturation ponds
Maturation ponds are the ponds that receive effluent from a facultative pond. They
are shallow, with less vertical stratification and are well oxygenated.
CONSTRUCTION 2010
36
2.0 WATER SUPPLY
An adequate supply of cold water of drinking quality should be provided to every
residential building and a drinking water tap installed within the building. The
installation should be designed to prevent waste, undue consumption, misuse,
contamination of general supply, be protected against corrosion and frost damage
and be accessible for maintenance activities. Figures 30 and 31 show a typical
layout of a domestic water supply.
Figure 30 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 660)
CONSTRUCTION 2010
37
Figure 31 (Adapted from: building construction handbook 6th edition by R. Chudley an R.
Greeno page 661)
CONSTRUCTION 2010
38
2.1 INDIRECT WATER SUPPLY
An indirect water supply system is the most common type found in modern houses.
The mains water comes in via a rising main and directly feeds at least one cold tap
at the kitchen sink with „potable‟ water (i.e. water which is fit for drinking,
cooking etc) and may also feed a washing machine, a shower and an outside tap
etc. The rising main also feeds a storage tank at a high point in the building from
where the water is fed to all the other taps etc using gravity. Figure 32 illustrates
this form of drainage
Figure 32 (Adapted from; /www.practicaldiy.com/plumbing/water-supply/indirect-
water-supply.php)
The items identified in the illustration above (NOTE that the central heating has
been omitted for clarity) of an indirect water supply are:
1. Water company stopcock
2. Householder‟s stopcock.
3. Draincock
CONSTRUCTION 2010
39
4. Storage tank with a ballcock float valve to control the water stored
5. Gate valve which can isolate the cold water feed to the hot water tank.
6. Gate valve which can isolate the cold water to the WC and taps etc.
7. Hot water cylinder.
8. Gate valve which can isolate the hot water to the taps.
9. Storage tank overflow pipe
10. WC overflow pipe
11. Inline valves to isolate water feeds to washing machine or dishwasher etc.
Advantages of an indirect water supply
It does overcome the problem of furring, therefore suitable for hard water
areas.
It reduces the risk of back syphonage and hence limiting contamination.
It provides a reserve of water should the mains supply fail or be cut off.
Disadvantages of an indirect water supply
This system requires more pipework than the direct system
2.2 DIRECT WATER SUPPLY
A direct water supply system is one where the raising main feeds directly the cold
water taps and a multi point water heater.
The mains water comes in via a rising main and directly feeds all the cold taps and
a multi point water heater - so all the taps and other water feeds are at mains water
pressure. Figure 33 illustrates this form of drainage
Advantages of a direct water supply
The main advantage is that drinking water is available from all cold water
outlets.
Disadvantages of a direct water supply
These systems are suitable only for areas with high level reservoirs with a
good supply and pressure.
Lack of reserve in case of supply cut off.
CONSTRUCTION 2010
40
Risk of back syphonage due to negative mains pressure and a risk of reduced
pressure during peak demand periods.
Figure 33 (adapted from /www.practicaldiy.com/plumbing/water-supply/direct-
water-supply.php)
The items identified in the illustration above of a direct water supply are:
1. Water company stopcock
2. Householders stopcock
3. Draincock.
4. Stopcock.
5. Gate valve which can isolate the cold water feed to the multi point water
heater.
6. Gate valve which can isolate the hot water from the multi point water heater
to the taps etc.
7. Multi water heater.
8. Inline valves to isolate water feeds to washing machine or dishwasher etc.
9. WC overflow pipe.
CONSTRUCTION 2010
41
3.0 Conclusion
During the four days of the practical part of this module different aspects with
in this scope of construction have been undertaken in and have yielded a
positive impact on my career development within the field of building
construction.
References
Construction technology hand books by R. Chudley and R. Greeno:
Editions 5th
,6th
, and 8th
www.practicaldiy.com/plumbing/water-supply/direct-water-supply.php
www.practicaldiy.com/plumbing/water-supply/indirect-water-supply.php
www.mfe.govt.nz/publications/sus-dev/integrated-whole-building-
design-guidelines/html/images/figure1.gif
www.wbdg.org/design/engage_process.php
Building technology hand book R. Chudley and R. Greeno 8th
edition