Sensitivity toward the environment - one of the key responsibilities that we have as an architect, can be achieved by choosing the right building materials and sourcing them locally. 

What are vernacular materials?

Materials that are indigenous to a certain region and can be sourced naturally for the construction of buildings. They are usually climate responsive and tie to the culture and traditions.

Some Sustainable Vernacular Materials

1. Cob
2. Rammed Earth
3. Bamboo
4. Stone
5. Lime 
6. Thatch
7. Wood
8. Laterite

1. Cob

• An abundant material seen in rural areas for construction of houses - cob is a material that is thermal resistant and windproof.
• It is suitable for extreme weather conditions - with porous and thick walls, creating a vacuum that does not allow heat to transfer easily.
• It is a mixture of the subsoil (ideally acquired during excavation for foundation), sand and straw along with water to bring it to the right consistency for moulding it into the required shape.
• The manufacturing of cob includes the following processes
  • Mixture of materials
  • Compression of mixture using bare feet
  • Sculpting using large balls of the mixture to build the walls

2. Rammed Earth

• As the name suggests, rammed earth construction involves compacting different types of soil into plywood frames. 
• Rammed earth construction is most suitable for areas with moderate temperatures and low rainfall. In case of extreme temperatures, additional insulation might be required. 
• The framework is constructed - consisting of two parallel plywood panels, into which soil is filled and compacted in layers. The soil that is added is compressed to at least half its volume before adding the next layer. 

3. Bamboo

• One of the strongest construction materials found in ample amounts in India - bamboo is a fast growing grass with many economic and structural benefits.
• After harvesting the bamboo, it must be treated with various processes before it is used for construction because when exposed to various natural factors it may easily deteriorate.
• Bamboo can be used in various parts of a building during construction - for roofing, flooring, walls, structural reinforcements, etc.

4. Stone

• Noted throughout the historical heritage sites of India - in temples and rock cut caves, stone is a material that is often carved to the required formwork.
• One of the most durable materials that will stand strong for generations, it requires very little maintenance and is suitable construction material for most climates. 
• Putting up a stone wall requires skilled labour - the gaps between the larger stones are filled with mortar and smaller stones. Stones are also a heavy material, which makes it difficult to place them at a height.
• Stones can be used in flooring, foundation, walls, structure and various other parts of a building which makes it a versatile material.

5. Lime

• Best known as a plastering material - usually one can observe a yearly lime whitewash done in rural areas. This is done not only for aesthetic purposes but also due to its various other benefits.
• Lime in construction can be applied in buildings in the form of plaster, mortar, putty and other finishing work.
• It is best known for its self-healing property (in cracks), insect repellent property and often used as a weathering course to maintain a cooler temperature in the interior of a building.

6. Thatch

• An eye-catching feature of south India’s houses are their thatched roofs - with dry fibres such as straw, reed and palm leaves bundled to form a roof.
• Thatch is versatile and can be used to cover different organic roof shapes - though thatched roofs are usually sloped for the water to run off quickly, in case of rainfall.
• It also proves to be a good material for insulation and roof covering because it is lightweight in nature and does not add load to the structure of a building. However, it is not fire-proof.

7. Wood

• An eco-friendly material that is biodegradable, recyclable and easily available in different regions - when used in construction, it reduces the carbon footprint of a given building.
• Wood is known for its thermal and acoustic insulation, resistance to fire and structural stability in buildings. 
• It can be used for the structural framework of a building or the framework of the interiors (such as door and window frames) and also in flooring, roofing and other parts of building construction.

8. Laterite

• Traditionally used in the western coast of India for housing construction - in the Malabar region and Goa, this attractive red stone is formed due to compaction of red soil.
• This rustic red stone is not only aesthetically pleasing, but also provides good thermal insulation and is eco-friendly because it does not generate any carbon footprint.
• Laterite stone is extracted and cut out from the ground using machinery - which does not include much manufacturing cost - making it economical.
• Usually used in construction of walls - similar to construction of masonry walls, using lime and soil.

The materials listed above are only some of the various sustainable materials that are used in India’s vernacular architecture. Each region has its very own tradition and style that uses locally sourced materials that are climatically responsive to that region. Exploration of different combinations of materials that are easily available in a certain area gives rise to these unique architectural styles.