Kerala Sloping Roof

Traditional buildings in Kerala, on the south-west coast of India, are recognisable by their roofs: long, steep slopes with deep projecting eaves that make the buildings look low and broad. The form is a response to one of the wettest climates in India, where the south-west monsoon brings intense rain for months each year, combined with strong sun for the rest of the year.

Structure

Kerala roofs are carried on timber. The roof frame rests on wooden pillars and wall plates, and carpentry was guided by an indigenous body of knowledge known as Thachu Shastra, the science of carpentry, which treated timber with great care. Laterite stone was widely used for walls, but the roof itself was a timber structure.

Key features include:

• Steep pitch to move water off quickly.
• Projecting eaves that keep rain and sun off the walls.
• Gable windows (mukhappu) at the ends of the roof, which ventilate the roof space when it is used as living or storage area.
• Inward-sloping roofs around the central courtyard of the nalukettu house type, where four halls surround an open court that admits rain and light.

Coverings

Most buildings were originally thatched with palm leaves, while clay tiles were mostly reserved for palaces and temples. During the British period, Mangalore-pattern interlocking tiles replaced older pan tiles and much of the thatch, and they became the typical covering of Kerala houses through the 20th century. Temple roofs sometimes carry copper sheet and copper finials.

Landmark example

Padmanabhapuram Palace, built in timber with sloping roofs, granite and rosewood and teak woodwork, is often described as the largest wooden palace in the world and is a major example of the style.

Relevance today

The principles of the Kerala roof, a steep pitch, generous overhangs and a ventilated roof space, remain directly relevant to building in any heavy-rainfall tropical climate, whatever covering is used.