The Following article was published in the June 2015 Edition of Domus India, documenting the building traditions and systems of 5 different rural regions of the country. The full PDF of the same can be downloaded here. Also can be found at http://www.domusweb.it/en/local-editions/2015/06/15/india.html
4. District Birbhum, West Bengal
Latitude: 23.91N; Longitude: 87.53E
Height Above Mean Sea Level: 54 m
Average Annual Rainfall: 1572.9 mm
No. of Precipitation Days: 68
Max. Summer Temperature: 38-39 degree Celsius
Min. Winter Temperature: 25-26 degree Celsius
Primary Materials Used: Cob (Mud balls), Laterite Stone, Bamboo, Mahua Tree Wood, Bitumen, Rice Straw Thatch, Termite mound mud, Reed
Language of the Indigenous Builders: Santali, Bengali
The Santhal tribals are the natives of the Birbhum District of West Bengal and they are expert cob builders. They are the third largest tribe in India and reside in parts of West Bengal, Bihar, Orissa, Jharkhand and Assam as well.
Santhal houses are generally G+1 with the cob walls rising to 18’ in height. Red laterite stone found in this region is used in the foundation and plinth as it stronger and more impervious to water than mud. These are not dressed. Thereafter cob walls start and their thickness ranges from 18” to 24”. All houses have an upper storey or attic which is used for sleeping, etc. This is made using bamboo and Mahua tree trunk, topped by bundles of reed and a 3” mud layer which forms the top of the floor. Windows and openings are generally small. Staircases are made with bamboo and mud to form the profile.
Pitched roofs of a steep 45 degree pitch are extensively found here and it is dictated by the limitations of the roofing material- rice paddy straw thatch. Any lesser slope would not have been able to handle the rain. Even though some families have switched over to Corrugate G.I. sheets, the steep pitch is still continued. Roof structure is made with bamboo and the mahua trees. These are either tied together or nailed.
External walls are rendered with bitumen or tar only up to a certain height. Bitumen is a very good waterproofing layer and this is exploited beautifully by the Santhals. Further up, external walls are lime washed and this process is in sync with socio-cultural customs and practices. The Santhal are very artistic in their expressions and this is evident in some of the mud relief work that they do on their walls.
- Sunderbans, District North 24 Paraganas, West Bengal
Latitude: 22.13N; Longitude: 88.5E
Height Above Mean Sea Level: 0-5 m
Average Annual Rainfall: 1559.8 mm
No. of Normal Rainy Days: 65
Max. Summer Temperature: 32-33 degree Celsius
Min. Winter Temperature: 24-26 degree Celsius
Primary Materials Used: Wattle And Daub (Mud plaster on wood/bamboo frame), Mud, Sundri Tree Wood, Rice Straw Thatch, Bamboo, Jungle wood
The Sundarbans delta is one of the richest ecosystems in the world. The region contains
arguably the world’s largest remaining area of mangroves, and is known for its exceptional
biodiversity, including numerous threatened species such as the Bengal tiger and
several species of river dolphin. It was accorded status of World Heritage Site by UNESCO in 1987.
This rich forest does not have a long history of inhabitation. In the early nineteenth century, the British East India Company leased out land to the Zamindars to harvest and clear out the forest, who in turn hired people from other parts of the state including indigenous tribals to carry out this task. These people cultivated the cleared land and became the first settlers of this region.
Ever since then, the preferred technique of building here is Wattle and Daub. Not a load bearing form of construction, this framed structure uses pillars and posts made of bamboo or trunks of the Sundri tree. Within this is frames is a complex mesh of bamboo strip or Sundri tree branches which are weaved together to form a porous membrane with air gaps in between them. A 1.5”-2” coat of mud plaster is applied on both sides of the wall thus forming a thin porous breathing wall. This works extremely well in the hot and humid climate here as the air circulation through the house enables cooling through evaporation of perspiration. Openings for doors and windows are left un-plastered.
Steep pitched roofs of bamboo are found here. Rice paddy straw thatch is the prevalent roofing material and the steep 45 degree pitch takes care of the water runoff. The bamboo rafters and trusses are connected to the vertical posts and the load is carried down to the ground through them. Due to the non availability of a strong impervious material, foundations and plinth are made of mud. Foundations are kept high, around 3’-4’ to account for periodic flooding that occurs here.
In many parts of the Sunderbans, the sea level is higher than the land level and there is an extensive set of mud and brick embankments to protect the land from the sea. This combined with periodic cyclones, floods and torrential downpour makes this a very intimidating place for human habitation.