A catalog of tools for the non-toxic builder/designer.
Tuesday, August 30, 2005
Developed by the Auroville religious community in Southern India and marketed by the Aureka Corp., the Auram 3000 represent the current state of the art in earthen block construction technology. The Auram is a variation of the 'cinva ram' developed in the mid 20th century for making Compressed Earth Blocks for use as a higher strength lower labor alternative to traditional earth blocks such as adobe and a more sustainable lower energy alternative to fired brick. But unlike all other cinva ram devices, the Auram uses a system of interchangeable steel molds which produce a large family of specialized precision block shapes. This allows for a versatility of earthen construction impossible with other techniques or devices. The Auram produces various forms of interlocking hollow blocks which reduce production labor, provide insulation, and which can be used in combination with poured concrete for hybrid construction that allows the earth block to be used for much more than simple walls. It's 'hourdis block' shape allows for the construction of CEB floor decks and roofs without the need for arches, vaults, and domes. Its 'U' channel block makes hybrid beams and lintels. Round column blocks can be used to make columns and posts, or in combination with pre-fab concrete step plates, to make spiral staircases. The high precision and uniformity of strength of the blocks as well as the ability to use hybrid concrete and earth composition allows for structures much larger and higher than typical with other earthen construction. Auroville has built earthquake resistant CEB buildings over 4 storeys high and domes and vaults over 10 meters wide. CEB has many advantages over other kinds of earthen construction. Small modular unit sizes make block construction easier for the DIY builder and the high precision and interlocking block shapes of the Auram CEBs minimize block laying labor by reducing the need for mortar and eliminating the need for special brick-laying skill. Using about 5-10% cement as stabilizer, CEB is more sustainable than other stabilized earth materials while still being resilient enough to be used without a plaster or adobe finish render. Traditional adobe MUST be protected by a finish render while cement and asphalt stabilized adobe doesn't always need a render but is so rough in appearance that it compels it just for aesthetics. Auram blocks fit together with only the slightest of visible seams and so have a very finished appearance without any other finishing needed -even in an indoor setting.
Used extensively throughout the Auroville community itself, the Auram is responsible for some of the most sophisticated and large scale earthen construction built to date. The Auroville Earth Unit web site contains numerous examples of their earth construction work and well showcases the Auram's versatility. And with CEB now under consideration as a key technology for the construction of settlements in space using at-hand indigenous materials, this technology may see a long future indeed.
In areas with relatively uncontaminated earth (sadly, a scarcity in some parts of the US) the Auram could be an excellent tool for the construction of economical non-toxic housing. It's potential for low-cost housing is well demonstrated in India and the Auram has been adopted by UNESCO for disaster relief housing construction. Because so much of the structure can be made out of the same simple material, cost is reduced by eliminating multiple trades and relying more on this single low-cost material while the reliance on a single material makes the whole task of ensuring low-toxicity much easier. The only downsides to the Auram are its reliance entirely on human labor -a virtue in energy-starved India but a liability in the US where labor costs are still much higher than fuel costs. Of course, for the extremely sensitive, the less one's building tools rely on fuel the less likely the chances of the building materials getting contaminated by exhaust or spilled fuels and oil. Purchasing a complete Auram package with all its molds would be a big investment for the DIY enthusiast, costing over $10,000, though the basic machine itself costs a couple thousand. Also, there is currently no place in the US where one can purchase these machines. They must be imported from India with at least a two-week delivery. Still, there is great potential in this product and the building system based on it. This author is currently considering becoming a US import dealer for this machine and would be interested in hearing from people who might want to use this building method in a demonstration.