As the Asia representative for the UNESCO Earthen Architecture program, the Auroville Earth Institute in South India is a great source for people wanting to learn earthen construction. In addition to building, they conduct research and development, operate training programs and publish books on the topic. Kiva Bottero spoke with Satprem Maini, director of the Auroville Earth Institute, about earth block construction and the push to mechanize this simple construction technique.
What does appropriate building technology mean to you?
Something that is appropriate in the place where you are and what is appropriate today might not be appropriate tomorrow. Building with compressed stabilized earth blocks (CSEB) is still appropriate right now, but not if done by hand.
Labour is now very expensive in India, and workers are difficult to work with and are working much less than before. So, we have to mechanize. This is one of India’s problems. You have more than one billion people, but you have problems getting workers on site. They prefer working jobs in a comfortable office in IT or whatever.
What is more cost effective, CSEB or rammed earth?
When you work by hand, rammed earth is cheaper. Ten years ago rammed earth was half the price of CSEB, but today that might not be the case because of labour increases.
Can you use any type of earth for CSEB?
Not all, but a lot of them. In general, it’s best to use sandy soils. Cement would be better suited as a stabilizer for sandy soils. For clay, lime is better.
Is lime much more sustainable?
Yes, but you need more of it than cement. It’s more sustainable in one sense because it gets fired at a lower temperature than cement—700 to 900 degrees, depending on the stone—as opposed to cement, which is 1200 degrees.
How much training does someone need to be confident enough to build their own home?
One month for an engineer or mason. More for a layman. I can quote an example. Two engineers from Colombia came here to take a one month course on the production and use of CSEB. One week is production of blocks, one week is masonry followed by learning arches, vaults and domes, which consists of one week of theory and one week of practice. They then went back to their country and built resorts and domes, schools, water tanks. This was a good success.
Do you see CSEB becoming more popular in the West?
If you have motorized machines, yes.
If you were to pick one project here in Auroville that best proves earth construction, what would it be?
Vikas community. It’s four floors built using CSEB. It also uses alternative energy like wind energy, solar and wastewater systems. This project was a finalist for the World Habitat award in 2000.
What’s the most promising technology you’re researching?
Poured earth concrete. It has a good future if you can find mixes with different soils and is a great alternative to cement concrete. I’d also like to develop alternative stabilizers to cement and lime that are not processed with high energy, but I don’t have enough people for that right now.
For someone interested in volunteering at the Auroville Earth Institute, is there a minimum length of time to commit?
It’s better if you stay four months because it gives you more time to learn different techniques and work on different projects. It’s on the job training. But we do accept people for one week or one month, but they’re just doing the basics—they’re having fun outside.
If you stay longer, you learn more techniques. Since it’s on the job training you help with whatever work there is. So if you come at the end of the project you have to help painting and plastering. If you come earlier, you build some walls, vaults and domes.
We also receive a lot of interns who work in the office making plans. This opportunity is more for architects and we ask for a minimum stay of four months.
For more information, visit Auroville Earth Institute.