HABITATINTL. Vol. 4, No. 3. pp. 285-290 Pergamon Press Ltd. 1980. Printed in Great Britain

The Case for Traditional Housing in Tropical Africa

PATRICK MORIARTY

Caulfield Institute of Technology, Melbourne, Australia

INTBODUCl-ION

Tanzania is a tropical country on the East Coast of Africa, with an area of about 900,000 sq. km. The population of approximately 16 million is over 90% rural, with most of the inhabitants still engaged in near-subsistence agriculture. Tanzania -and indeed tropical Africa in general -is fortunate from a housing viewpoint in having such a large percentage of its population rural, as housing needs are more easily satisfied there than is possible in the urban centres. In rural areas, the materials for traditional housing types are still widely available, as are also the skills needed to fashion them into a dwelling.

In common with most of the countries in tropical Africa, Tanzania has only recently (1961) emerged from European rule. During this period, stretching back into the 19th century, Africans came into contact with Western housing styles and materials; some as labourers building houses, others as servants cleaning or guarding them or merely as residents of-or visitors to- the towns. The European housing styles in Tanzania were very different from local ones for a variety of reasons, but one important consideration must have been the following: to justify their “civilising mission” -a colonial (or trusteeship) authority can hardly afford to find much of value in local technology.

For whatever reason, this contact with the transplanted Western housing styles had a profound effect, given the prestige universally accorded to dominant new technology. Not only was the effect felt on the physical form of a small but increasing number of dwellings throughout the country, but more importantly for the majority who could not afford to build with the new materials, on their ideas as to what constitutes a good house, and thus on their aspirations for the future.

PRESENT STATE OF BUILDING TECHNOLOGY IN TANZANIA

Before the coming of the Europeans, all housing in Tanzania was built solely from locally- available materials, such as mud, poles, thatch and stone. These materials are still the most commonly used, but the picture is changing, especially in urban areas, as is evident from Table 1.

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Table I. Building materialsfor housing in Tanzania

Building National Component Material Urban % Rural % Average %

Foundation No foundation 40 93 90 Stone, concrete, etc. 60 7 10

Floor Earth 34 92 89 Concrete, stone, etc. 66 8 11

Wall Poles and grass 16 36 35 Poles and mud 28 44 43 Mud bricks 16 16 15 Burnt clay bricks 8 2 3 Cement-based blocks, concrete, stone, etc. 32 2 4

Roofing Thatching I3 73 70 Mud 1 12 II Metal sheeting 77 I3 I6 Concrete, tiles, etc. 9 3

Source: Adapted from Edvardsen and Hegdal. 1971.1

Earth is clearly still the dominant material used for walls, foundations and floors. Even in urban areas, dwelling walls are still more commonly constructed from the traditional material than from the more recent burnt clay bricks or cement-based blocks.

The great majority of urban dwellings are roofed with corrugated iron sheets, and even in rural areas metal sheet roofing is fairly common - nationally 16% of dwellings are so roofed. It is also evident from Table 1 that metal sheet roofing is the first housing innovation usually made: in rural areas, for example, although 13% of houses have metal sheet roofing, only about 4% use modern wall-building materials. In fact a house in either urban or rural areas with a traditional roofing material such as grass thatch combined with a modern wall material such as cement-based blocks is a very unusual sight.

THE WESTERN INFLUENCE ON AFRICAN HOUSING STYLES

The impact of European housing technology has changed African housing designs, or at least, housing aspirations, in two major ways: first, in the choice of building materials and, secondly, in the physical form of the dwelling.

(a) Materials

The previous section documented the extent of the use of modern materials in one tropical African country, Tanzania, and showed that it was especially prevalent in urban areas, where cash incomes are far more common than in rural areas. Most dwellings, however, even those in urban areas, still contain elements of traditional housing materials or construction.

The materials used in European dwellings differ from those used in African housing chiefly in being highly engineered and durable materials, with the result that the production of these materials is highly energy-intensive. Chapman2 has analysed the fuel costs for a three-

‘Edvardsen, K. I. and Hegdal, B. “Rural Housing in Tanzania: Report on a Prestudy”, National Housing and Building Research Unit, Research Report No. I, Dar-es-Salaam, 1972.

ZChapman. P. Fuel’s Paradise. Penguin, London, 1975.

The Case for Traditional Housing in Tropical Africa 281

bedroom semidetached 100 sq. m. brick house in the UK. The total fuel cost is about 3.7 x IO5 MJ thermal, with over 80% of this figure used for materials manufacture, and the remainder used for construction of the house itself. Bricks are the most important consumers of fuel, with steel and the cement-plaster-concrete group of materials also important fuel consumers. The durability of these materials gives the dwelling a long useful life, and the high strength materials enable two-storey dwellings to be constructed without changing the materials used. Also, two-storey construction enables land requirements to be minimised. In Tanzania, at least, two-storey dwellings are not common, but the trend towards the use of high energy-cost materials, especially cement and metal sheets, is evident from Table 1 above.

(b) Physical form

The design of houses has perhaps been altered more than the materials used, if only for the reason that the modern materials are expensive, whereas design changes need not be so.

In the first place, the shape of dwellings has altered: for example the traditional hemispherically-shaped hut of grass and poles, with no clear distinction between walls and roof, is giving way to rectilinear construction, with mud increasingly displacing grass as the wall material. (The mud itself is being replaced, albeit slowly, by cement-based blocks3) One important reason for this change in dwelling shape may be that it is perceived as being more “modern”, but the chief reason appears to be that the hemispherical shape cannot be easily adapted to metal sheet roofing, as can the hipped roof of the earth- or block-walled houses.

Another important difference between European and traditional African housing has led to another change evident in present-day African housing layout. In European dwellings (whether in Europe or Africa), all rooms are placed under the one roof. This makes sense in a cold climate, since heat loss is reduced by minimising external wall area, and heat generated during cooking or water-heating can be used to warm the entire house. The compact design, as well as the use of two-storey dwellings -also thermally efficient -saves space in urban areas.

In tropical Africa, especially in the coastal regions, it can be argued that it is better for the cooking area to be separate from the living and sleeping areas, because of the heat generated. Similarly the placing of the toilet indoors makes sense in a cold climate and if water-borne sanitation is provided, but pit-latrines are best sited at some distance from the main dwellings. In general, in hot humid climates a dwelling compound composed of several buildings will allow for maximum ventilation. However the high cost of modern materials will be a strong force in grouping all building under the one roof, as this allows savings on the cost of exterior wall construction.

A final difference should be mentioned. In Dar-es-Salaam a number of two to four-storey flats have been built. The result is that the area immediately around the one-storey bungalow, which is used during the day-time just as intensively as the dwelling interior, is lost for upstairs occupants. The effective living area of their dwelling has thus been reduced. Again, a sensible adaption to a cold climate transfers badly to the humid tropics.

3Edvardsen and Hegdal, op. cit.

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EVALUATION OF TRADITIONAL HOUSING

It should be made clear that in Tanzania and elsewhere in tropical Africa there are both well-constructed and poorly-constructed dwellings built from traditional materials. It would be a mistake to condemn traditional housing as inadequate for meeting minimum shelter needs from observations in slum areas of cities, just as it would be mistaken to condemn modern materials and construction methods by observing only slums in the West. There are houses built of traditional materials in which the foundations and drainage are inadequate for the site, the walls off vertical, and the thatching carelessly constructed. It is the well- constructed houses which demonstrate the potential for using the traditional materials and associated skills.

The traditional building materials in Tanzania, grass or palm thatch, stones, earth and bush-poles are all familiar and locally-available building materials, requiring only very simple equipment for their preparation and use in construction. Further, they require no input of fossil fuels, relying on renewable solar inputs to dry mud blocks and grow the thatching material and bush-poles. From this it follows that construction with these materials is very cheap and thus available to all Tanzanians.

Further, these materials are not necessarily only temporary solutions. Earth, at least, can be used as a permanent wall material provided simple precautions are taken during various stages of construction.4 For example in Dodoma, in central Tanzania, the author inspected a mud-block house 35 years old, the home of one of his students. The rainfall over these years (at about 1000 mm/year), had only removed about one centimetre of the earth wall (measured by comparing the lower blocks with blocks under the protected eaves), which is of minor importance in a wall over 30 cm thick. There is even less reason for replacing interior walls of earth construction with cement-based blocks (or other modern materials), as in a well- constructed dwelling interior walls will not suffer any change in moisture content, and thus will not deteriorate at all. Thatching does suffer from lack of durability, although this problem is probably not as serious as it may first appear. A well-constructed roof thatch may last 7 years. The repair and eventual construction of a new thatch can be done in the slack season, when agricultural work tapers off.5 This work can be seen as analogous to the maintenance and painting that needs to be done to a Western-style house. Furthermore, increasing the roof slope and increased compaction and thickness of the thatch can greatly increase both impermeability and durability.

In any case, roof thatching needs to be compared with its chief competitor -which in tropical Africa is corrugated iron sheets. The advantages of metal sheet roofing appear formidable indeed. It is strong and light (and thus easily transportable and breakage- resistant), durable and impermeable. It is easy to fix to a roofing frame, which need only be light, locally-available bush poles. In fact, although a modem material, it involves less skill than is involved in constructing a good thatch roof. But the metallic crystal structure which is responsible for the high strength/weight ratio and durability of metal roofing sheets is also responsible for its major drawback (apart from its expense): metal sheets are very good

4Moriarty, P. “Earth Wall Construction: A Tanzanian Case Study”, International Conference on Materials

of Construction for Developing Countries, Bangkok, August, 1978. SMoriarty, P. and Svare, T. 1. “Housing Materials and Methods for Tropical Africa”, Euihfing Research ad

Practice, London: Vol. 4, No. 1, Jan.-Feb. 1976, pp. 28-35.

The Case for Traditional Housing in Tropical Africa 289

conductors of heat and the lightweight sheets have a very low heat storage, making them less suited climatically to the tropics than thatch roofing. Finally, thatch roofing escapes the steady hammering noise produced by heavy rainstorms beating on sheet metal roofing.

THE DFSIRABILITY

commonly-used traditional materials in Tanzania and elsewhere in tropical Africa lie in their low durability, while the chief problem facing the modern materials is their cost, whether measured in energy or in money terms. But, regardless of whether traditional or modern materials are used, or a mixture of both (which is common), it is argued here that the only realistic way of providing dwellings for all the people is by encouraging the of self-help housing.

Promotion of self-help housing has two main justifications.

satisfaction, but also reduces the one-sided dependence of ordinary people on various experts or government The of owner-constructed

multi-storey flat construction,

multi-storey flat include increased living space per household for the same or lower urban plot ratio as one-storey bungalow housing, and also the use of modern building technology in solving the “housing problem”. There are, how- ever, serious disadvantages, the main one being the high cost per unit area of floor space relative to one-storey construction, residential, of similar standards. Nor can the units’ cost be easily lowered, as the wall and floor-slabs must all be load-bearing, necessitates the use of high strength, high energy and high dura- bility modern materials (especially reinforced concrete) as well as sophisticated

construction. For taller buildings, lifts and possibly pumps to boost water pressure will be needed. In any case water-borne sanitation and provision for interior cooking are essential. The high costs of and maintenance mean that only housing needs of a minority can be satisfied in this manner.

Unlike self-built one-storey bungalow construction, multi-storey block cannot be extended or modified significantly

multi-storey housing to satisfy urban African housing needs implies that people are to be dependent on others for housing, as the traditional building skills would be rendered obsolete. In brief, is expensive and socially damaging: not only does it not make use of the skills, materials and

6Turner, J. F. C. “The Re-education of a Professional” in Turner, J. F. C. and Fichter, R. (eds.), Freedom to Build, Macmillan, New York, 1972.

‘Illich, I. Toolsfor Conviviulify, Calder and Boyars, London, 1973.

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methods locally available, but also social needs met by one-storey bungalows cannot be satisfied in multi-storey flats.

If it is agreed that dwellings as far as possible should be one-storey bungalows, even in urban areas, then there still remains the question of who should build them. Simply put, one- storey bungalow construction is easy enough for local people to either build them directly themselves, or, at the least, organise their construction. For one-storey construction, with the light roofing frame needed for thatching (or metal sheeting), safety considerations are not important, as they must be in multi-storey construction. It is important to realise also that even the new materials, cement-based blocks and metal sheet roofs, are amenable to self-help construction.

CONCLUSIONS

This paper has outlined the present state of housing materials and technology in Tanzania, a typical tropical African country, and shown the trend, especially in the urban areas, towards modem materials such as metal roofing sheets or cement-based building blocks. These new materials, which in contrast to traditional materials have a high energy cost, are one result of the impact of Western technology on housing in tropical Africa. The importance of Western technology is also evidenced by the shift towards rectilinear design of dwellings, with all living areas under the one roof.

Traditional housing, whether by necessity or choice, still forms the bulk of dwellings in tropical Africa. It has two key advantages: first, that it uses only renewable sources of energy and materials for construction, and, secondly, that it is built or at least supervised by the occupants themselves. These related advantages are so important for the provision of adequate housing, that it appears essential to encourage traditional housing, or some modified form of it which will largely fulfil these two criteria. This support could be provided in the following ways:

(1) Governments in tropical Africa must encourage the use of traditional materials and design by using them, where at all appropriate, in government buildings. Traditional building materials will get little support if governments still build multi-storey office blocks and housing schemes which necessitate the use of high-strength modern materials.

(2) The building research centres in these countries must work to improve the traditional materials and designs, if at all possible.

(3) New materials, if used at all, should be selected so that they are amenable to self-help con- struction, and should have as large a local input as possible. An example is cement-based blocks, where cement is the only non-traditional material; the aggregate and the labour to make and cure blocks can be supplied locally.