Roofing in East Africa

Across East Africa, from the Kenyan coast to the highlands of Ethiopia and the Great Lakes, the roof that dominates towns and villages is the corrugated metal sheet, known throughout the Swahili-speaking region as mabati. It has largely replaced the grass and leaf thatch that covered most rural houses within living memory.

Traditional roofs

Traditional houses across the region were usually round or rectangular, with walls of poles, mud and wattle, and conical or pitched roofs of grass or palm thatch. Round houses with conical thatched roofs, structurally similar to the Southern African rondavel, with radial rafters meeting at an apex, were widespread. On the Swahili coast, coral-stone houses had flat roofs on mangrove-pole joists, and rural coastal houses used makuti thatch of coconut palm leaves. Pastoralist communities such as the Maasai built low houses of branches and mud with flat or gently curved roofs plastered in mud and dung.

Mabati

Corrugated galvanised iron, patented in Britain in 1829, spread through East Africa in the colonial era and after independence. It is light, quick to fix and easy to transport, and it allows rainwater harvesting. It is widely used in informal settlements and has become a marker of a "modern" house in rural areas. Regional manufacturers now roll galvanised and zinc-aluminium-coated steel, in corrugated, box-profile and tile-effect forms, often pre-painted.

Drawbacks are well known: thin sheets make houses very hot by day and cold at night, rain on metal is loud, and corrosion is a problem near the coast or where rainfall is acidic.

Other modern roofs

Reinforced concrete flat roofs are common on urban apartments and commercial buildings. Clay and concrete tiles, and stone-coated steel tiles, are used on middle- and higher-income houses.

Climate

Much of East Africa lies near the equator but at altitude, with two rainy seasons and strong sun. Good overhangs, insulation or ceilings beneath metal sheets, and secure fixing against storm winds are key design concerns.