Bhutanese Shingle Roof

The traditional roof of Bhutan is a broad, gently sloping roof of loose wooden shingles held down by stones. It sits on a timber frame lifted clear of the top of the walls, leaving a tall, open loft beneath that air can blow straight through. Seen from a distance, the roof seems to float above the house, which is why it is sometimes described as a "flying roof". The same type of roof traditionally covered farmhouses as well as the great fortress-monasteries (dzongs).

Construction

The roof frame is built of hardwood and bamboo and, like other traditional Bhutanese carpentry, is assembled without nails. The covering is made of pine shingles laid loose on the frame. Rather than being nailed, they are held down by laths laid across them at regular intervals, with stones placed on the laths. The Folk Heritage Museum in Thimphu, housed in a mid-18th-century farmhouse, notes that such roofs were designed to withstand severe winter winds.

Under the roof, the space between the top of the walls and the shingles is left open at the eaves. This ventilated loft is used for storage and for drying chillies and animal skins, and is insulated in places with bamboo mats and hay. Traditional roofs have decorated timber cornices but no rain gutters.

Dzong and temple roofs

Dzong roofs follow the same principle on a larger scale, with flared roofs over the inner temples and heavily decorated eaves. Buddhist temples (lhakhang) are often crowned by gilded copper roofs or roof ornaments. Timber shingles weighted with stones were the original covering of dzong roofs; Trongsa (Tongsa) Dzong keeps one of the few surviving shingle roofs, which was being restored in 2006-07.

Change

Almost all dzong roofs, and most houses, are now covered with corrugated galvanised iron instead of shingles, and metal shingles are increasingly chosen for their durability. The heavy use of timber leaves traditional buildings vulnerable to fire and decay.

The form of the roof is protected even where the material has changed. A royal decree of 1998 requires all buildings in Bhutan to have sloping roofs, along with traditional painted timber fronts and small arched windows, and the code of etiquette known as Driglam Namzha sets out traditional rules for dzongs and ordinary buildings.