Roofing in West Africa

West Africa spans the arid Sahel, the savanna and the humid coastal forest belt, and its traditional roofs reflect that gradient: flat earth roofs in the dry north, thatched conical and pitched roofs in the savanna and forest zones. Today corrugated metal sheet and reinforced concrete dominate new construction.

Sahel: earth roofs

In the Sudano-Sahelian zone, from Mali and Burkina Faso to Niger and northern Nigeria, buildings are made of earth using the banco technique of sun-dried bricks and earth plaster. Roofs are flat or slightly domed, built of timber and mud; the eastern Hausa tradition uses more timber than the western one. The Great Mosque of Djenné in Mali, rebuilt in 1906-1907, has a mud-covered roof of rodier palm timber, with vents capped by removable fired-clay bowls and ceramic spouts that carry rainwater clear of the walls. Its walls and roof are replastered each year by the community.

Savanna and forest: thatch

Further south, round and rectangular houses traditionally carried conical or pitched roofs thatched with grass or palm leaves over timber or bamboo frames, steeply pitched to shed heavy rain.

The shift to metal

Corrugated metal sheet is now the most common roof across the region, valued for low cost and speed but criticised for heat gain and dependence on imports. Long-span aluminium and coated steel sheets and stone-coated steel tiles are popular on new houses in coastal cities.

Earth alternatives

Since 2000 the association La Voûte Nubienne has promoted the Nubian vault, an earth-brick vault built without formwork or timber, as a roofing alternative in the Sahel. It reports more than 8,500 buildings completed and more than 4,900 masons trained across seven countries.

Concrete

Reinforced concrete flat roofs and slabs are standard on urban multi-storey buildings and many houses, often built incrementally with rebar left exposed for future floors.

Climate

Heavy rainy-season downpours, intense sun and harmattan dust all affect roof performance and maintenance.