Low Cost Housing ResearchesBuilding and Road Research Institute (U.

of K.)

PREPARED BY:

ZUHAL ELTAYEB AWAD

YUSIF TIBEN MUSA

December 2009

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Abstract This paper presents summary of the findings of someresearches on Low Cost Housing :-

- Low Cost Housing Study (1982).-Low Cost Housing Project (2006).-Factors and Building Elements Contributing to AffordableHousing for Urban Dwellers (2001).

The paper presents the outcome of the low cost housing study(1982) which is a construction project for the Khartoumregion. The project examined successively the plotting, thebasic core, extensions, assemblies and the low costsanitation systems.

The paper focuses on the low cost housing project (2006) andpresents the proposed pilot house type (3) with emphasison : plotting , the basic core, extensions, foundation type,walling units and roofing system.

The paper reviews the out come of the analysis andrecommendations of the study of the factors and buildingelements contributing to affordable housing for urbandwellers (2003).

The paper concludes with some outlines for important areaswhich need future research such as :

- Land utilization and adequate space utilization - Planning and Design of housing clusters and housing

units

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- Building elements (foundation, walls, roofs, etc) - Development and promotion of manufacturing of raw

materials - Promotion of the existing potentials of building

industry - Financial resources and lending policies for the low

income groups - Provision of adequate services

1- Introduction

Shelter is a basic need for human beings. The problem ofshelter in Greater Khartoum.- The capital of Sudan- isevident in the high need for housing and deficient supply ofhousing.The Building and Road Research Institute (BRRI) is concernedwith the housing problem and several researches have beencarried out to find solutions to that problem especiallyhousing projects for the low income groups.This paper presents summary of the findings of someresearches :-

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- Low Cost Housing Study (1982).-Low Cost Housing Project (2006).-Factors and Building Elements Contributing to AffordableHousing for Urban Dwellers (2001).

The paper examines the outcome of the low cost housing study(1982) which is a construction project for the Khartoumregion. The project examined successively the plotting, thebasic core, extensions, assemblies and the low costsanitation systems. The proposed sanitation systemsincludes;-

- Improved privy with a ventilated tank.

- Agua privy with a direct fall.

The paper focuses on the low cost housing project (2006) andpresents the proposed pilot house type (3) with emphasison:-Plotting, the basic core, extensions, assemblies, foundationtype, walling units and roofing system. The paper reviews the out come of the analysis andrecommendations of the study of the factors and buildingelements contributing to affordable housing for urbandwellers (2003).

The paper concludes with some outlines to guide futureresearch on low cost housing.

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2-Low Cost Housing Study (1982).The government of the Democratic Republic of the Sudan andthe Agency Cooperation et Management are established a lowcost housing study. The cooperation et Management signed acontract on December 23, 1982 with the Building and RoadResearch Institute (U. of K.) to participate in preparingthis study.The study includes:-

- Institutional and Financial Context.- Design layout devices of pilot schemes.- Low cost sanitation systems.- Roofing Systems.- Earth construction techniques.- The production of burned bricks in the Sudan and its

improvements.- Lime study.- Plaster in the Sudan.

Construction Project for the Khartoum Region

The project is an approach which may lead to numerousdifferent alternatives.This solution originates from the desire for compatibilitywith the proposed sanitation systems and making possible thedirect transfer of some of the urban management problems toa resident community by creating semi-public spaces, and forconsistency with the ways of life of the vast majority ofthe population.The project examined successively:-

- Plotting.- The basic core.- Extensions.- Assemblies.

Plotting

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The proposed layout of the plots must meet the followingrequirements:

- 10 to 20 plots must be grouped around a semi-publicinterior space accessed by narrow pedestrian ways.

- The size of the plots shall vary (180 to 220m2).- Each plot shall be accessible by a road suitable for

cars.- There shall be two entrances to a plot, one on the car

road and the other in the inner space.- The north-south aspect shall be preferred to provide

the optimal ventilation in relation to prevailingwinds.

- The sanitary blocks (toilet and shower) shall begrouped at the rear of the plot in the inner spaceside.

- The inner space shall be large enough to provide a playground for children or sports ground.

The study examined several layouts with their advantages andtheir drawbacks. The selected alternative (see fig. (1)) is the one whichseems to meet best the requirement for the least amount ofmoney and which because of its size is best adapted to theimplementation of a pilot project.

Advantages

- Good ventilation of all plots.- Simple design of the plots plan.- Direct access for cars of all plots.- Savings on sewage network.- Good dimensions of the inner space.

Drawbacks

- Risk of monotony on a larger scale.- Considerable size of public spaces.

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This solution is the one answering best the requesteddemands in terms of economy. The fourteen plots are groupedaround the inner space which is accessible by means ofnarrow pedestrian passages (3m large). Ten of these plotstype A (10x20) (see fig. 2 &3) are facing North-South and four of them Type B (12x18) (see fig. 4 &5)

Plot surface : 64%

Private or semi-private surface : 81%

Density : From 160 to 250 people/hectare.

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Proposed layout of plots

Fig (1)

Fig (2)

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House plantype (A)

Views house type (A) Fig (3)

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House plantype (B)

Fig (4)

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Views house type (B)

Fig (5)

The Test Houses

The test house includes a basic core which can be easilyexpandable by the addition of one other room or more.

The basic core

It includes:-

- A block with a surface of 32.20m2 consisting in thesala and one adjustment room slightly set off.

- A water block at the rear of the plot with toilet andshower (surface : 2m2).

- A fence (2m high) with two accesses.

The layout of the basic core meets the climatic cultural andeconomic requirements:-

- Transversal layout in relation to prevailing winds(North-South).

- A few or no openings on the East and West facades forprotection against the sun.

- Direct access for visitors to the reception area.- Intimacy provided by the physical separation of the

reception areas and the areas for family activities.- At the rear of the plot separate access for the family,

leading to the common inner area.- At the rear of the plot free space for family

activities.- Possibility to park a car near the access on the road.- Direct access for visitors to the toilet.- Basic core laid out with common walls.- Construction of common walls to facilitate a future

expansion.- Water supply located at the rear of the plot (toilet, shower)

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The sale and bedroom block

- The sala is a covered area with a surface of 20m2

(5.9x3.42) with large openings and where most familyactivities take place. The adjacent room with a surfaceof 11.70m2 (3.42x3.42) will be used as a bedroom orreception room.

The block is built with lime stabilized earth blocks onburned brick foundations and it has a flat roof – apossible alternative is a single-pitch roof made ofasbestos-cement. The openings are built according to abearing-out system in order to save on lintels. It isalso possible to build relieving arches. The heights havebeen determined in accordance with the thermal comfortrecommendation.

The water block

This block is located at the rear of the plot it includesa toilet and a shower. The proposed sanitation systemsare:

- Improved privy.- Aqua privy.

The Extensions

The design of the basic core makes it possible to buildan other room or more for future enlargements. Example :

I. Basic core + one kitchen (2.18 mx2.80 m) the totalsurface 40.3m2.

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II. Basic core + one kitchen + two bedrooms (11.70 m²)the total surface is 52m2.

III. Basic core + one kitchen+ two bedrooms (11.70 m²) thetotal surface is 63.7m2.

These extensions are built with lime stabilized earth blocksand they have an asbestos-cement single-pitch roof.

As in the case of the basic core the openings are builtaccording to a bearing-out system.

It must be noticed that a one storey vertical extension maybe considered. It would provide two additional bedroomsabove the basic core.

Low-cost Sanitation System

The proposed system has to meet certain conditions: thesystem must be cheap, not public, require little or no safewater, operate even in case of improper use, require littlecontrol, not need a cesspool, catch all waste waters, treatthem appropriately so as to avoid any risks for users andnot need mechanical equipment.

It is difficult to meet all these conditions simultaneously.It will therefore be necessary to take certain options andto favor certain aspects taking into account the specificproblems of Khartoum.

The proposed systems are:

- Improved privy with a ventilated tank.- Privy with a set-off and ventilated tank (single and

double).- Aqua privy with direct fall.

Discharge of the outflow through a soak away. Discharge of the outflow through an absorption

field.

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Improved privy with a ventilated tank.

This system is similar to the pit latrine largely in use inpopular neighborhoods.The differences are basically thefollowing:-

- Installation of a ventilation system with a diameterof 15-20cm; fitted at the end with wire netting. Thissystem is intended for odour exhaust and catchinginsects.

- The shed must be roofed and fairly dark so that theinsects coming inside may be attracted by the lightcoming from the ventilation system and trapped into thewire netting.

- The cesspool shall be of a reasonable depth 3-8mapproximately. It is necessarily emptying the cesspoolperiodically once every 5 years.

Privy with a set-off and ventilated tank

The operation of this system is fairly similar to that ofthe previous one. The proposed system uses two tanks whichare set off in relation to the seats. The first tank is useduntil it is full. It is then tightly closed and the secondtank becomes in use. It takes about one year to fill eachtank. When the second tank is about full, the first one isemptied (either manually or mechanically). The wastes aredischarged in a land fill. The first tank is then used againwhile the second one is closed. The two tanks are thus usedby turns.

The tanks are set off in order to provide for easieremptying as well as to prevent the shed from collapsing, asit is already occurred in the Sudan.

Aqua Privy

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Before installing this system, it will therefore benecessary to launch an information campaign for thepopulation. However, it has been included in proposalsas it is the only one which makes its possible, for alow cost, to channel the effluent to an absorptionfield after settling and pre-treatment.

This solution is interesting, because it uses theweather conditions instead of the purifying power ofthe soil. This is particularly interesting as regardsblack soil for cotton growing.

3- Low Cost Housing Project (2006)

This study of Low Cost Housing is prepared in response to arequest by Savings and Social Development Bank. The studycovers planning and Design of Three types of houses:

Type (1) : Compact design with vertical development .

Type (2) : Compact design with possibility of verticalextension.

Type (3) : Scattered design with horizontal development.

The Pilot House Type (3)

The house type (3) is a semi-detached house designed for thelow income group. The paper will focus on housestype ( 3 ) and it will examine successively.

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Plotting

The lay-out of the plots has to meet the followingrequirements.

- The cluster contains 64 plots with two symmetrical openspaces (30.4m x 40m) (see fig (6) ).

- The size of the plots are the same (13.2x20) 264m2.- Each plot shall be accessible by a road suitable for

cars-10m wide, inner corner plots opening onto anotherpedestrian road-8m wide and outer plots opening onto alarger open space.

- There shall be one entrance to a plot on the car roadand the corner plots have two entrances.

- Each two houses have shared walls of the built area.- All plots are North-South to provide the optimal

ventilation to the built area.- The sanitary blocks (toilet and shower) shall be

grouped at the front of the plot.- There shall be one soak away pit for each two houses

located in the road.- The inner open space shall be large enough to provide a

play ground for children.

The core unit

- The houses type (3) which intend to build on theselected sites in Khartoum and other parts of Sudaninclude a basic core unit, water block, a kitchen andwall fence. The core unit can be lived in immediatelyand can be expanded in future by the addition of otherspaces (a room, a sala, a veranda) See Fig (7&8).

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Fig (7)

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House plantype (3)

Views house type (3)

Fig (8)

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The core unit includes

- A main block with a surface area 37.5m2, consisting ofa sala (4.8m x3.6m) and one adjacent room (4.5m x 4.5m)forming L shape.

- A kitchen at the rear corner of the plot with a surfaceof 8.7m2.

- A water block (toilet + shower) at the front side ofthe plot with surface of 5.4m2.

- A fence 2.20m high with one access.

The localization of the basic core meets the followingclimatic, cultural and economic requirements:

- The lay-out in relation to prevailing winds (North –South).

- No openings on the East-West sides for protectionagainst the sun.

- Direct access for male visitors to the reception areaand rear access for females and family members andvisitors.

- Physical separation of the reception areas and theareas for the family activities.

- Free space at the front of the plot for guestentertainments at early mornings and evenings.

- Free space At the rear side of the plot for familyactivities.

- Construction of shared walls between each two houses.- Direct access for visitors to the toilet.- Water supply located at the front of the plot for the

water block and extended to the rear side of the plotfor the kitchen.

The main block

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- The main block consists of a sala and a room . The salawith a covered surface area (4.8 m x 3.6 m ) 17.28m2

where most family activities take place. The adjacentroom with a surface area of (4.5 m x 4.5 m) 20.25m2 maybe used as a reception.

This block is built with stabilized earth on reinforcedconcrete. strip foundation and it has a ribbed roof. Theopenings are semi-arch and made from steel. The heights are3.0m.

The water block

This block is located at the front of the plot. It includesa toilet and a shower. Sanitation is improved aqua-privy.Each two houses share one soak-away pit outside of the plotsSee Fig (9 ).

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The Kitchen

The kitchen has a surface area of (3.6 m x 2.7m) 8.72m2 .Itis located at the rear corner of the plot and has two sharedwalls with other two plots.

The extensions

The design of the basic core makes it possible to buildother spaces for future extensions. For these extensions wepropose possible lay-outs which meet the requirementsalready mentioned. The extensions may be built in stages.

Example:-

(I) Basic core plus one room (20.25m2). The total surfaceis 71.9m2

(II) Basic core plus one room plus a sala (20.5m2) and averanda (8.7m2). The total surface is 1022.2m2.

(III) Basiccore plus one room plus a sala plus a veranda plusanother room (14.4m2). The total surface area is115.5m2

Foundation Type

Foundation is the most important structural compound ofbuildings and if not properly designed; the life time of thebuilding will be tremendously reduced.

Foundation type for any building depend mainly upon the following aspects:

(i) The sub-soil conditions.

(ii) Type and amount of loadings.

(iii) The environmental conditions.

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Under normal condition (non-problematic sub-soils), andlight loads, the strip-foundation type is the best option toadopt. The strip foundation shall be rigid enough and ofsuitable size to transfer safely the loads due to buildingto the underneath soil strata without successivedeformations or settlement. Also the strip foundation shallbe situated at sufficient depth to avoid seasonalfluctuation of the ground moisture. Concrete on grade stripfoundations (beams), stepped masonry strip foundation (rock,brick blocks) build with cement sand mortars; or with dryrocks strip foundation (foundation trenches filled withcompacted rocks and granular material) are the mostconvenient types of footings or load bearing walls .

The reinforced concrete strip foundation had goodperformance records , can withstand aggressive environmentalconditions and transfer evenly the exerted loads, canwithstand large deformations however its cost is relativelyhigh.

The masonry stepped strip footing is suitable where firmsubsoil strata are encountered. It is relatively cheapcompared with reinforced concrete strip, if properly sizedand can transfer loads safely, but its construction needsskilled labour, sound masonry units (rocks, blocks bricks)shall be sound to absorbent water. This type of foundationcan not withstand large deformations.

The dry rock strip foundations although intended to absorbthe swelling pressures of the soil beneath, but individualrocks tends to rotate or fracture, under loads, thusinducing movement to the wall above leading to wallcracking. Also in case of a localized wetting of the soilbeneath, the individual rocks can sink independently causinglocalized arch like failure for walls. Needless to say thatamong all of the case studies of wall building failures

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conducted in the BRRI, the dry rock fill foundation was themain contributor to these building failures .

During the study of the project of the low cost housing theoption of the reinforced concrete strip foundation wasselected to be suitable for most of sites despites its costimplications. Some modifications were made to the stripfoundations to improve their performance in sites whereproblematic soils (expensive soil) are dominant .

The construction technique for strip foundation is rathersimple straightforward and needs less formwork, but certainprecautionary measures are needed to be taken for optimumutilization of materials and better performance of thefooting , these include the following:-

(i) The foundation trenches (excavation) shall extend wellbelow the active zone of the expansive soil, and belowthe loose top soils.

(ii)The bed of the trenches in site of expansive soils,shall be overlaid by a cohesive compacted non-expansivesoil layer to act as a cushion between the natural soiland the strip foundation.

(iii)The materials used (concrete) and workmanship adoptedshall be of good quality.

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Walling units

Stabilized soil bricks will be the walling units for theproposed housing project due to availability of main rawmaterial ( in situ-soil) and because it is easy to produceand to build with and expected to be cheaper in comparisonwith other building materials.

Materials Used In Production of Stabilized Soil Bricks

Many types of soil can be used in production of stabilizedsoil bricks provided that it contains appreciable amount offines (silt and clay). The type of soil in other hand,determines the type of stabilizer, in sandy soils cement isthe suitable stabilizer, whereas lime is suitable forclayey soil.

The following table gives some indicators for particle sizedistribution of soil which are thought to be suitable forproduction of stabilized soil bricks.

- Gravel 0 – 40%

- Sand 25 – 80%

- Silt 10 – 25 %

- Clay 8 - 30%

Technology for Production of Stabilized Soil Bricks

Different types and sizes of stabilized soil bricks can beproduced where blocks (290 x 140 x 100 mm) and bricks canbe produced, only by changing moulds.

Good production depends on thorough dry mixing of soilalone and then soil and stabilizer. Water is added asmixing is proceeding.

The type of soil and stabilizer determine the quantity ofwater added, but it is generally slightly drier as than

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optimum moisture content (o.m.c) for sandy soils andslightly wetter than (o.m.c) for clayey soil.

The percentage of cement is generally between 4 – 8% byweight of soil weight where as the percentage of lime lyingbetween 6 – 12% by weight of soil weight.

The forming pressure should be high in order of 150 -180bar , wherever pressure is high the density of producedbricks will be high and accordingly less waterpermealituy , become the goal of stabilization( compression and additional of stabilizer) is to increasewater resistance of soil . After production, the bricksleft for curing for period not less than 14 days, knowingthat the sufficient period for stabilization is 6 months.

The most suitable environment for curing is the hot humidenvironment; this is why curing under direct sun and underplastic sheets will rise both temperature and humidity

Properties of Stabilized Soil Bricks

4.1 The most important property of stabilized soil bricks isits resistance to water (immersion, capillary action,sprinkling etc)

4.2 To have reasonable compressive strength when wet andthat wet strength in half dry strength.

4.3 Variations in dimensions should be kept to the minimum.

Roof System

Roof is the building element that offers the users or occupantsof the building, the necessary shelter against the sun rays andlights, wind and storm, rainfalls and snowfalls, dust falls, andthe day and summer heats and the nights and winter colds for thisreason any person who possessed a shed is considered protected.

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Different types of roofs and roof materials are known to be used for buildings these are:-

(i) Traditional ( local) roof, straw and mud roofs, (Baladi)(ii) Corrugated sheet roofs.(iii) Timber boards roofs (iv) Jack arch roofs.(v) Ribbed slab roofs(vi) Reinforced concrete, slab roofs(vii) Ferocement roofs.

a) The traditional / local roofs are constructed from the nearby forest /farms materials. It is composed from a main beam,timber pole, joist and secondary beams , wood purlins,overlayed by palm leaves, straw and a layer of mud andplastered with zibala, mortar of animal residue and finestraw. Such type of roofs although are easy to construct butthey have short life time, needs periodic maintenance andconsidered hazardous to environment.

b) The corrugated sheet roofs are lighter offers betterappearance to roofs, especially slopes roofs, easy to erect,needs less maintenance. Different materials are used for thecorrugated sheets, such as iron asbestos, etc. Thecorrugated iron roof sheets are the most widely usedespecially in urban areas, however these roof sheets aregood conductors to heat and colds, rendering the interiorenvironment of the building unfriendly for this reason, somemodification or improvement are needed, such as sandplasting the sheets or simply by adding a false ceilingbelow. Obviously such modification increases the overallcost of the roof element. The asbestos roof sheets proved tohave hazardous effect on human health and is no longer used.In the Building and Road Research Institute (BRRI), a

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research was conducted to use kenaf fibers and cementmortars for the production of the corrugated roof sheets.The researchers concluded that it is visible and possible toproduce such roofs sheets. One of the BRRI workshops(Carpenter workshop) in addition to a primary school of ElHag Yousif were roofed with these sheets a pilot project forthe industry and the interested bodies and persons.

c) The timber board roofs depends mainly on timber products(boards, joist..etc.) needs treatment against insects, shallbe water proofed by overlaying them with waterproofingstreets, have less life time for all these reason such roofsare scarcely used these days and even if used they aretemperate nature.

d) The Jack Arch roofs (English Arch) are well known roof typessince the nineteen century. The were used before theconcrete inventions. Jack Arch roof composed of hot rolledsteel joist as main beams and brick vaults supported by thebeams. These type of roof have a good performance recordsand is suitable in aggressive environments and can supportupper floor loads. However, its construction technique needsspecial care.

e) Ribbed slab roofs (one way or two way) normally used inlarge span slab where it is necessary to reduce own weightof the slab to control deflection. The ribs are fromreinforced concrete and the voids between ribs are filledwith bricks (hollow or solid) and overlayed by a reinforcedconcrete topping. The rubbed slab can be designed as a flooror roof and needs formworks and shuttering to construct it,it offers good interior appearance and living environment.

f) Reinforced concrete slab roofs/floors are mostly and widelyused in multi storey structures. The reinforced concreteslab needs also formworks and shuttering to constructs andit offers good interior appearance and living environmentand can resist higher live loads.

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g) The ferrocement roofs were studied in Sudan (SUST). Thesetype of roofs are classified as shell roof (vaults ordomes). The shell is constructed form expanded wire meshformed into the desired shape and them covering that meshwith cement /sand/aggregate mortar. These types of roofs areonly suitable for a single storey building and needsformworks and skilled labour.

A cost study was carried out in the BRRI for the different typeof roofs and the results of the study are shown presented below.

Item Type of Roof Roof Cost ratio totraditional

1 Local/traditional 1.02 Corrugated iorn sheet 1.03 Ferro-cement 1.254 Corrugated sheet plus false

ceiling1.4

5 Ribbed slab 2.26 Jack Arch 2.47 Reinforced concrete slab 2.9

During the study for the savings and Social Development Bankprojects, the option of the ribbed slab roof was chose for thefollowing reasons:

(i) Easy to construct.(ii) Offers good appearance and interior environment.(iii) Durable i.e. long life time.

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(iv) Can support floor live loads if vertical extension isintended.

(v) Relatively of low cost if combared with R.C. slab orjack arch.

4- Factors and Building Elements Contributing toAffordable Housing for Urban Dwellers (2001).

The study covers aspects related to the cost of housing inits different parameters whether planning, design, andconstruction, building materials or finance. The main objective of the study is to analyse the cost of different building elements and components to identify the most promising areas in which appreciable cost reduction could be

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achieved since cost of housing is greater than to be met by the urban poor.

The study is based on the local conditions and it dealt with single storey load bearing buildings due to the fact that multi story buildings are affordable to the high income segment of the population. For the purpose of the analysis a model dwelling unitdesign is worked out from the most popular house design since design is adebatable issue. The model dwelling unit is then divided into construction stages i.e. sub-structure and super- structure.

Building elements in each stage were further divided into components and each component is assessed in terms of cost of materials labour and over- heads set in a form of analysis table.

From this table the cost of different elements and components were compared so that the most critical cost items could be identified. Then critical cost parameters wether materials. Labour or over- heads were discussed and comments regarding the required intervention that may bring their cost down are stated.

The analysis carried out in the study revealed that buildingmaterials were found to be the bottle neck in the process ofhousing unit construction. A maximum cost reduction could beobtained with optimum utilization of labour, materials and equipment as chief production factors.

Standardization is an important principle inrationalization and requires that the dwelling unit shouldbe built of standardized components. This can apply todimensions, materials used, composition of materials,characteristics etc. This will make mass production ofhousing possible thus reducing cost per housing unit.

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The analysis also revealed that the most costly elements inthe construction of the dwelling unit were found to beroofs and walls respectively. It is important to findmethods to modify the existing types and also to seek toinvent suitable alternatives for them at an acceptablecost.

Concerning sanitary systems the analysis discovered thatthe septic tank and cess-pool system proved to be the mostexpensive on site disposal systems. The use of sharedcommunal discharge system, such as, shared septic tanks andcess-pools for a number of dwelling units can result in aconsiderable reduction of cost of such a system but thisrequires some institutional arrangements, such as, permitsfrom local authorities. The traditional pit latrin is found to be the cheapest onsite disposal system, yet it is not the ideal one. Its costcould still be modified through the decrease of the depthof the pit but this will necessitate the improvement ofmaintenance service.

Concerning sewer system, the analysis discovered that theintroduction of a shallow sewer system might be an adequateoption since its cost can be shared by a number of plots(e.g. 20 plots for a single sewer).The system is mostsuitable for housing schemes rather than individual housingunits. One of the privileges of this system is that itcollects all waste water from the household solving theproblem of wastewater.

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Conclusion

The process of housing provision is a complex process , itinvolves many activities ( eg the provision of land ,planning, design and building of housing unit).Many factors govern this long process, in order to providecomprehensive low cost housing projects, research workshould study better utilization of all those factors.

Here are some out lines for important areas which needfuture research: -

- Land utilization and adequate space utilization,research should be tend to optimize the size of plotsand adopt optimum standards of services.

- Planning and Design of housing clusters and housingunits should be oriented towards reduction of space(open areas, streets and plots).

- Building elements (foundation, walls, roofs, etc)should be thorough studied in order to be developed.

- Development and promotion of manufacturing of rawmaterials to substitute imported building materials.

- Promotion of the existing potentials of buildingindustry in the formal and informal sectors.

- Availability of Financial resources and lendingpolicies for the low income groups.

- Provision of adequate services (water supply, sewage,sewers, electricity, cabbage collections.

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References:

- Ministry of finance & economic planning. Low cost housing study – final report- book 1. January 1984.

- Abdalla Salah Eldin Abd Elrazic. Factors & building element contributing to affordable housing for urban dwellers – the case of Khartoum. August 2001.

- B.R.R.I Study of low cost housing for Saving & Social DevelopmentBank. Final report. September 2007.

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