Roofing in the Middle East and Gulf

Across the Arabian Peninsula, the Levant, Mesopotamia and the Gulf, the defining roof is flat. Flat roofs are an ancient form, characteristic of Egyptian, Persian and Arabian architecture, and remain the norm for new buildings in the region today.

Why flat roofs dominate

In hot, dry regions with little rain, a roof does not need a steep pitch to shed water. Masonry and concrete roofs keep out solar heat thanks to their mass and are economical where timber is scarce. Flat roofs also provide valuable outdoor space: for sleeping on hot nights, drying crops and laundry, and, today, for water tanks, air-conditioning plant and solar panels.

Traditional construction

Traditional flat roofs were made of timber poles or palm trunks spanning between thick walls, covered with layers of palm fronds, mats or reeds and then compacted earth or gypsum plaster. Spans were limited by the length of available timber, which in turn limited room widths. Where timber was even scarcer, rooms were roofed with masonry vaults and domes of mud brick, baked brick or stone.

Windcatchers

Tall ventilation towers, called barjeel in the Gulf and badgir in Iran, rise above flat roofs to catch breezes and vent hot air. In traditional Gulf merchant houses they were one of the main means of cooling before air conditioning. Windcatchers are seen as part of the shared architectural heritage of Iran, the Gulf and Egypt.

Modern practice

Reinforced concrete slabs with insulation and waterproofing are standard. Common waterproofing systems include bituminous and modified-bitumen membranes, single-ply membranes and liquid-applied coatings. High solar radiation and roof temperatures demand UV-stable materials, light or reflective surfaces and insulation, often placed above the waterproofing in inverted roof assemblies. Drainage falls are essential because ponding water accelerates deterioration; good practice aims to clear standing water within 48 hours.

Rain and dust

Although rain is infrequent, intense storms can overwhelm poorly drained flat roofs. Dust and sand abrasion also shorten the life of exposed membranes and coatings.