At one with nature

Sustainable Construction

Modern earth houses of Bangalore have shown that it is possible to construct them in such a way that they have all the present-day conveniences with a look and feel that is contemporary, apart from being sustainable, explains Sharath Nayak.

India has traditionally used earth for building walls except in cases of larger loads and monumental construction where stone was used instead of earth. Where stone was a rarity, present as it was mostly in the flood plains of rivers, clay was abundant and was fired to make bricks. Various techniques of wall building such as cob, abode, wattle and daub or rammed earth were used.

Modern times have seen a gradual shift towards concrete and steel in construction. These are materials with high embodied energy. There is a need to look at alternative methods of construction that are ecological, low in embodied energy, and cost-effective while not compromising on structural aspects—sustainability being the key factor for such constructions.

Earth construction is slowly being adopted in urban India, especially in Bangalore and Auroville located in Pondicherry, thanks to extensive research work and built examples done in the Centre for Sustainable Technologies, Bangalore and Auroville Earth Institute, Pondicherry.

Earth construction is a reliable alternative to burnt bricks, concrete blocks or stone. It is estimated that Bangalore is the city with the most number of modern earthen buildings with about two thousand of them. Many architects use this material because of their low-cost, ecological credentials as well as their aesthetics.

Most of such buildings source the earth from the site itself. For sites in the City, a basement space is designed and this space, apart from providing the earth for the construction, is also a space which can maintain a steady, comfortable temperature throughout the year.

On larger sites, the earth can be got from excavations for ponds which can then become a part of the water harvesting and treatment systems.

Use of blocks

The most common method of earth building employed in Bangalore is by making blocks out of the soil. These blocks are called Stabilised Mud Blocks (SMB) or Compressed Stabilised Earth Blocks (CSEB). These blocks are made on site using a manually operated machine. Bangalore now has a good ecosystem to apply this method.

There are teams of compressed earth blocks makers, a high level of construction knowledge amongst masons, and a support network of engineers to construct and detail structural designs. Apart from the walls, these blocks can be used in building roofs as well by using techniques like precast arch panels, vaults and domes.
Another technique of wall building which is gaining popularity is rammed earth technology.

In this technique, a formwork of either wood or steel is used into which the earth is poured and then rammed. This kind of a wall has fewer joints when compared to a wall built of stabilised mud blocks and has an aesthetic appeal of its own. In both these techniques, the walls can be finished without the use of plaster and paint.

Consumption of steel, cement and sand in such buildings are considerably reduced.
Adobe and cob are traditional wall building techniques. Bangalore also has a couple of modern cob and adobe homes.

Cob is one of the easiest and most inexpensive ways of building with earth. It does not need any machine or formwork. In this technique, one makes lumps of earth with one’s own hands.

These lumps are then used to build walls, and the experience is very similar to sculpting with clay. Adobe is a technique in which a small mould or form is used to shape the earth into a brick. These bricks are then sun-dried and used to build walls.

A frequently asked question about mud buildings is, ‘How long will these buildings last?’ If the building is designed with the right details appropriate to the climate of the place, a mud building can last as long as any other. Research work into the material and techniques has enabled mud walls to now be thinner and not occupy too much space as the mud walls in traditional buildings, without compromising on the structural integrity.

In terms of cost, they do not cost more than a building built out of conventional materials.

Modern earth houses of Bangalore have shown that it is possible to build in a way that makes such homes sustainable, have all the present-day luxuries and conveniences, and have a look and feel that is contemporary.