In Andhra Pradesh’s coastal areas, where cyclones are common, the locals build circular mud houses that can withstand winds of up to 250km per hour. This vernacular architecture technique of Andhra uses locally-available construction materials and is eco-friendly, sustainable and low-cost.
Called Chuttillu, which means a circular house in Telugu, these structures are built by farmers and fishermen in the cyclone-prone areas of the East Godavari district. This local architecture minimizes carbon footprint as only local materials are used for construction.
Chuttillus are constructed close to each other in a circular formation so that the cyclonic winds that often hit the coast bounced off tangentially away from the cluster.
Design of Chuttillu
These traditional homes have a thatched conical roof and a circular house plan with concentric walls, making them cyclone resistant. The concentric pattern gives rise to an inner safe space for the family and an outer transitional space, which has a grain storage area on one end and the kitchen at the other end.
The inner rooms are used as an attic for storing valuable assets in times of floods and cyclones. The width between the two consecutive walls is around 1.5 metres. Small openings are made on the outer wall for ventilation of the kitchen and storage area.
The outer wall holds the conical roof at an angle of around 45 degrees from the horizontal to ensure that rainwater does not stay on the roof. The roof is thatched with palmyra leaves and other locally available materials like unused fisherman’s nets. Sometimes tyres and heavy earthenware are tied to maintain pressure over the roof.
Due to the slope and thatching, the roof comes down very low on all sides including the entrance. This roof overhang protects the mud walls from rain.
Outside the main housing area, there is a small alternative cooking area for summers, called the vantsala, a battery for chickens and a shelter for the bullock cart called the aedul bandi jaaga.
The round structure and high-pitch roof of the house add to the aerodynamic feature of Chuttillu. The houses have two openings – one in the front and the other at the back.
In the case of a cyclone, the high-pitch conical roof is difficult to uplift and allows the wind to pass over it while the two openings allow the release of pressure.
The external pressure and suction acting on the structure get evenly distributed due to its circular configuration, preventing damage.
Chuttillu houses are, in many ways, similar to Bhunga houses built in Gujarat’s Kutch region, which is prone to earthquakes. During the devastating Bhuj earthquake in 2001, the Bhungas were not damaged. Since chuttillus are built close to one another, they allow the strong winds to flow tangentially across them.
Construction of chuttillu
A Chuttillu is raised on a mud plinth on which circular dimensions are marked with hands using rice paste or red ochre. The concentric walls are erected over the markings on the floor.
The houses are built using the wattle and daub construction technique where vertical wooden wattles or stakes are interwoven with horizontal twigs and branches and then daubed with clay or mud.
In Chuttillu, bamboo slits are woven with bamboo or casuarina posts and then daubed with mud.
For daubing, the cob wall technique is followed where mud is mixed with sand and straw. The balls of mud are placed closely in a row to build up the wall. Only about two feet of the wall can be erected in a day. It is allowed to dry completely before the next two feet are built the following day.
The walls are then given a lime wash for the finish.
Chuttillus have been included in the DakshinaChitra Museum of art and architecture where the structure has been recreated by the residents of the Haripuram village in Yellamanchilli Mandal of Visakhapatnam District in Andhra Pradesh.