Roofing in Southeast Asia

Southeast Asia is tropical, with heavy monsoon rains, high humidity, intense sun and, in the Philippines and Vietnam especially, typhoons. Traditional roofs across the region are steep, with deep eaves and well-ventilated roof spaces, usually over timber or bamboo houses raised on stilts.

Traditional forms

• Indonesia - roofs are central to cultural identity, from the horned gonjong of the Minangkabau rumah gadang, thatched in sugar-palm fibre, to the boat-shaped bamboo roofs of the Toraja tongkonan. Clay tile is now very common: about 90% of houses on Java use clay roof tiles, a practice that spread among commoners only in the late 19th century under Dutch colonial encouragement.
• Philippines - the bahay kubo has a tall, steep roof of nipa, cogon or anahaw thatch, sometimes laid as halved bamboo (kalaka). Colonial-era bahay na bato used curved Spanish tiles and later galvanised iron.
• Thailand, Laos and Cambodia - tapered flat clay tiles have been used since at least the 9th or 10th century, and traditional houses are raised on stilts, often to head height, in flood-prone river and canal settlements.
• Vietnam - ancient stilt houses had roofs that curved up like a boat or down like a turtle shell, and imperial palaces used glazed tile roofs in white, blue, yellow and green, while ordinary northern houses were timber or thatched.

Modern roofing

Corrugated and profiled steel sheet, often zinc-aluminium coated and pre-painted, is now the most widespread roofing across the region's towns and villages because it is cheap and fast to install. Concrete and clay tiles are common on suburban houses, and reinforced concrete flat roofs are standard on urban shophouses, tube houses and apartment blocks. Many traditional roofs, including those of rumah gadang and tongkonan, are now re-covered with corrugated metal.

Climate considerations

Key design concerns are rapid rainwater shedding, generous overhangs, ventilation of hot roof spaces, insulation or reflective coatings under metal sheet to reduce heat and rain noise, and secure fixing against typhoon winds.