“Alternate and Appropriate Locally Available Housing Construction

Materials: The Case of Zimbabwe”

Chiedza Manyepa – B. Arch. Studies (Hons), B.ArchDepartment of Architecture, National University of Science & Technology,

Box AC 939, Ascot, Bulawayo, Zimbabwechiedzamanyepa@gmail.com / cmanyepa1695@nust.ac.zw

Lookout B. NdlovuMechandra Consulting Engineers, Zimbabwe

lbndlovu@gmail.com

Introduction • Lots of factors affect housing delivery

process• Eg legal security and tenure, availability of

services, materials and technologies, facilities and infrastructure, affordability, habitability etc

• Focus of paper on two related issues– Affordability – Materials and technologies

Introduction (Contd) • lack of adequate and durable housing is seen as one

of the most pressing problems facing humanity• Main reasons are

– the growing population,– rapid urbanization in towns,– rising costs of construction materials– large gap between supply and demand– inappropriate housing policies– land delivery and planning bottlenecks– lack of finance– low affordability among the majority – recurrent droughts leading to diversion of funds to relief

operations.

Introduction (Contd) – excessive building regulations, by laws, standards and

codes. – Increased inflation leading to a decline in construction

activities– Inflation leads to an increased raw-material price. – government economic reforms geared towards privatizing

economies.• Interventions have achieved little success• Focus been on using conventional building

materials, skills and equipment. • The resulting shelters are available to a few,

culturally inflexible, environmentally destructive, energy intensive and expensive.

Introduction (Contd) • The reality is that Zimbabwe does not have adequate

capital resources to construct houses using the conventional materials.

• Therefore strategies and technologies that will allow prospective householders to build within the limitations of their own resources must be adopted

• Low cost housing should be looked at.

Background to study • The problem of housing in Zimbabwe is further

exacerbated by• Economic and political turmoil over the last two

decades.• Land reform program, new farmers and the governing

authorities are facing great challenges in setting up decent structures.

• The new areas often lack the basic social amenitieslike schools and hospitals.

• Operation Murambatsvina / Drive out Filth victims still trying to build

Background to study (Contd) • Since the formation of the Government of National Unity

in 2008, the shortage of materials has eased out.• However their high costs and low affordability are still

major challenges.• Government housing policies and programmes skewed

towards urban housing.• Conventional and modern housing components or their

constituents are ‘imported’, their prices are beyond the reach of many, their manufacturing plants and transportation consumes lots of energy and are also characterized by high carbon emissions in their production

Low cost housing• Shelter crisis requires new solutions, new policies, new

tools, new measures and efforts• Low cost housing is one of the measures promoted. • Options explored in low-income housing by various

organizations include;– Review of standards– reducing dimensions of buildings. – provision of unserviced sites and land,– availing building mortgages and other financial assistance to

both prospective house owners and service providers

Low cost housing (Contd) – rationalized building procedures and standardized designs, – promotion of performance based standards for traditional

materials and alternative material.– use of local appropriate materials and technology (ICS and

others).• After independence, the Government of Zimbabwe

took an active role in provision of low cost housing• Some of the programmes it was involved in include;

• Warren Park D in 1985.• Government Construction Units (GCU) within the MPCNH

Low cost housing (Contd) – Kuwadzana Extension development - joint venture between

Zimbabwe Building Society (ZBS), a local private building society and GS Holdings.

– Partnership with USAID through the PSHP embarked on mass production of housing units in urban areas in a five year program.

• These interventions brought about some positives.• Primarily to reduce the overall costs.• Increased affordability levels from 23% to 70% of

the total urban dwellers at that time.

Low cost housing (Contd) • However low cost housing should not be about reduced

size, quality, and standards to ensure affordability.• It should be about efficient design, use of appropriate

construction materials and techniques to reduce the overall cost but retain all the comforts of the conventional building systems.

• In essence low cost should not necessarily imply low value, it means affordable. Low cost really means high value in terms of money.

Low cost housing (Contd) • Building materials absorb most of the cost in

housing construction, closely related to construction techniques and labour. In a normal housing unit, building materials account for abou60% of the basic input and the cost component often goes up to between 70 and 75% for low-income group houses. Therefore, costs of building materials is what is rendering house construction of adequate size and quality well beyond the poor and low income earners.

Low cost housing (Contd)

• Because construction materials contribute a greater fraction of the total cost, it is necessary to develop and promote appropriate materials from locally available resources.

Appropriate Construction Materials

• ICS an institution within the framework of UNIDO has a new materials division.

• looks at the utilization of local materials, as well as wastes in housing and building sectors

• It partakes in capacity building in design, manufacturing, testing, and evaluation of these materials, and has thus initiated inter-regional co-operation amongst a number of developing countries.

• In the same manner, the Building Centre Movement (BCM) has spearheaded the transfer and use of technologies in housing construction in India.

•

Appropriate Construction Materials (Contd)

• In the same manner, the Building Centre Movement (BCM) has spearheaded the transfer and use of technologies in housing construction in India.

• It has set up more 385 building centres throughout the country since 1986.

• The initiative has achieved great success in developing and commercialization of alternate building materials from waste and local sources.

• One example is the utilization of fly ash in clay fly ash bricks, fly ash paints, fly ash polymer composites, fly ash concrete blocks, pulverized fly ash cement and in lightweight aggregate. (Rai and Prasad, 2006)

Appropriate Construction Materials (Contd)

• Another success story is the promotion of bamboo as a green building material.

• It has varied applications such that it is now called the ‘in India.

• Bamboo composites have applications in transport, packaging and furniture. In housing it has been applied in; partition walls and ceilings, door and window shutters, bamboo laminates for floors and roof coveringi.e. corrugated bamboo mat board, bamboo columnsset in concrete footings, bamboo trusses or rafters supporting bamboo purlins and in wall infill panels.

Appropriate Construction Materials (Contd)

• In the African Sub-continent, examples are• Sisal fibre as reinforcement of gypsum in East Africa• Bamboo fibre roofing sheets in Nigeria . • Sisal cement roofing tile projects have been in

Tanzania and Kenya. Rice Husk Ash cement is also used as alternative cement for Kenyan building industry

• This shows that locally available materials and waste have the potential for applications in building components manufacture.

Appropriate Construction Materials (Contd)

• Regionally, there is research underway in Botswana to establish a framework for developing performance based codes in Botswana, South Africa and Zimbabwe

• The University of the Witwatersrand and Hydraform have achieved reasonable success in the use of earth, ‘sludge’ precipitated at the water treatment plant, fly ashand bottom ash for the production of masonry elements

• The Hydraform technique has recently been approvedfor application in Bulawayo.

Promoters of Appropriate Materials and Technology in Zimbabwe

• Practical Action – demonstrated low–cost energy efficient technologies as

alternatives to fired farm bricks. – explored a range of stabilized earth plasters.

• Scientific and Industrial Research Development Centre (SIRDC) – adopted the rammed earth technology and the Micro Concrete

Roofing (MCR) tiles for commercializing the projects locally– Have developed standards and registered with the Standards

Association of Zimbabwe.– In partnership with DFID they stabilized Kalahari sands with

fly ash & cement for Blair pit latrine construction in Tsholotshoand Lupane districts.

Promoters of Appropriate Materials and Technology in Zimbabwe

• Ministry of Local Government, Public Works and Urban Development (Hlalani Kuhle at Whitecciff farm)– SIRDC - rammed earth technology model house– Practical Action - stabilized soil model house– Forestry Commission - wooden model house

• Habitat For Humanity in Zimbabwe (HFHZ)– Built houses from baked brick, with a concrete floor and

concrete tile roof as a replacement of of mud walls and thatch• Zimbabwe Women Construction Association (ZWICA)

– Brick making and tile making using coal combustion waste among other materials.

Promoters of Appropriate Materials and Technology in Zimbabwe

• In spite of the energies spent on evolving appropriate and cost effective technologies

• The initiatives are not finding much application and successin the field.

• Technologies are applied without taking consideration of local climatic conditions and cultural values.

• The subdued enthusiasm, is because technologies promoted are not local.

• Emphasis has been on adopting technologies from other countries or regions developed in a different context to that locality’s own conditions.

Promoters of Appropriate Materials and Technology in Zimbabwe

• This calls for research on appropriate materials that areavailable within the locality.

• The bid to reduce the way ward exploitation of the earth’s resources has led to what is termed AppropriateTechnology in building industry. Other terms that have cropped up are needful and sustainable, alternative, green building and natural.

• It is from this dimension of appropriate technology that this paper wants to assist in tackling the housing problems in Zimbabwe in areas under similar socio-economic situation.

Identified Appropriate Materials• The choice of construction technology is not a linear,

simple, logical and orderly process where choice is based on technical appropriateness for sustainable use

• it is a complicated process affected by; – cultural, – social, – economic, – environmental and – political factors prevailing at the given time. • Therefore the material chosen or developed should

be structurally sound and satisfy most of the following

Identified Appropriate Materials– Benefit local economy by income generation; – Be affordable; – Socially acceptable; – Aesthetically satisfying; – Culturally acceptable; – Utilise locally available material; – Utilise local skills, man power and management skills;– Functionally effective.

Identified Appropriate Materials• Thatch roofing• Earthen construction• Waste based materials • Alternative green building materials• Fulfill most all the above demands at a comparative

cost to conventional materials.• Focus is on alternative materials and not traditional

materials.

Alternative Building Materials• Agricultural waste• Industrial waste• Mining waste• Available in Zimbabwe can be used for economic gain and more

so in low cost rural housing. • Plant fibre based materials another source • Zimbabwe has limited alternatives for roofing material in rural

housing. • This sub-sector will benefit from development of agricultural

waste. • The development of plant fibre based materials will be a real

innovation in Zimbabwe instead of just tinkering the existing methods of construction

Identified Appropriate Materials• These wastes include rice husks, bagasse, coffee

husks, sisal wastes, cotton seed husks, nut shells, saw dust and other wastes from cotton ginneries, coffee processing, paper mills, sugar factories, textile factoriesoil factories, polymer processing, sawing mills etc.

• These wastes produced at crop processing sites which can be easily collected and developed into constructionmaterials among other things to benefit of the locality.

• Mine wastes and sediments from large water treatment plants also come into mind.

• Coal combustion waste not just housing building but general construction should be explored.

Identified Appropriate Materials• It is already envisaged that fly ash will be used as

cement replacement in the construction of the Gwayi-Shangani Dam superstructure.

• In Binga the BaTonga have been using grain crops stalks for roofing for ages. Improved techniques can be applied all round to make them more sustainable..

Identified Appropriate Materials• The use of waste augurs well for the initiative of promoting

building materials produced from locally available renewablesources.

• Identification and evaluation of waste is the first step in considering their use in housing construction. There is needto undertake more research work on their properties (physical, mechanical, structural, performance and quality), development and standardization, technical performance.

• The results of further studies will form national guidelines and specifications on use of agricultural waste.

• The database should also comprise construction technologies, equipment and skills required.

Identified Appropriate Materials• As there is no inventory on these resources, the

creation of a data base is the first step in the positive direction for facilitation of research and developmental work.

• Information in this section indicating the vast scope and potential for the utilization of fibre waste based and industrial waste based resources

• It is hoped that it will go a long way in stimulating activity in promoting increased and more rational use of alternative building materials for low cost housing.

CONCLUSION• In the face of a growing population, inadequacy of

traditional materials and shortages of building materials, the emerging secondary raw materials in the form of waste based and plant fibre materials have an important role to play in the provision of low cost housing in rural areas.

• As agriculture is the main economic activity in the country, agricultural waste can provide a strong option as a source of affordable durable materials. Agro wastehas the potential of replacing or reducing the use of expensive materials such as cement and steel

CONCLUSION

• Focus should be on working on ensuring the appropriate and sustainability of the identified materials for improved housing.

• This is the effective utilization of waste products and at the same time acting on the improvement of the appropriate traditional housing construction materials.

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Acknowledgements

• Many thanks to the organizers of this conference, the SAHOUSING FOUNDATION Team, and Stacey Jonas for her patience with us while we prepared thisreport;

• Our families and friends;• The National University of Science & Technology;• The Bulawayo Home-Seekers Consortium Trust (BHSCT);• Government of Zimbabwe through its various Representatives• And All our Sponsors.

Thank you all for listening;and God Bless.