Monday, December 13, 2010

Earthbag (rammed earth in a bag) building. I like.

I've been lurking around the Earthbag Building Blog, the blog arm of earthbagbuilding.com, for a while now and I the idea of earthbag building has seriously grown on me.

The basic idea is to take a common resource, dirt, tamp it down into a bag, and stack it into walls. Now the first image that I though of was of sandbag bunkers and levies, and thats basically the same thing. The difference between my, Vietnam era firebase, sandbag bunker and a earthbag home is the way the bags are packed and connected. Often times soil is packed in to make the bag as dense as possible and rows of bags are connected using barbed wire as "cement".

Once the bags are layed up, windows and doors framed (box frames are secured right onto the bags), and the roof built (by traditional trusses or earthbag domes), then an earthen plaster is applied to seal the bags and finish the walls. Earthen plaster is a reoccurring theme in sustainable building, namely because of its world wide ubiquity and its durability. You might remember a small discussion of earthen plaster in my post about strawbale building and how it provides a active vapor barrier that allows vapors to pass in an out of a structure without trapping them, which causes mold and mildew problems.

A completed earthbag structure is among the most durable in the realm of sustainable building, surviving almost all natural disasters or at least surpassing the survival rates of conventional methods. This makes for a impressive structure at a potentially $0 pricetag. Considering that foreign food aid comes in bag form, think rice and grain bags, the price tag of building these structures can be very low if not zero, excluding labor costs. The third world and emergency situation implications are tremendous. Currently earthbag buildings are being promoted in Haiti, which still lies in ruins after the January 2010 earthquake. The US Military has even offered workshops in Djibouti, to teach those who are interested how to build affordable shelter. Earthbags have also seen widespread adoption across the continent of Africa, and Middle Eastern countries, including Iraq, Afghanistan, and Pakistan.

For those of you wondering about where you might find sandbags take a look here or here for ideas. A box of 1000, surplus GI, sandbags runs about $360, not bad considering the comparative cost of conventional building supplies.

Earthbags might be a new take on the rammed earth idea, but the idea itself is one of the oldest in the world. Rammed earth structures have been around since man figured out that earth is compactable. Here is a link to a rammed earth watch-tower, built in China, that dates back to the Han Dynasty (200's BC). My thinking here is pretty cliche, if it ain't broke.... So given that this building style has been around for thousands of years in one way, shape, or form, perhaps it deserves more attention from the modern home building community and sustainability activists. I'd love to see how this method of construction would survive Northeastern winters, and springs for that matter. If it turned out that it was a viable building style then I'd love to live in something so simply build, timelessly beautiful, and completely sustainable.

2 comments:

  1. maybe you could build a little test-hut somewhere and see how it holds up through the winter... probably too late to try this year though

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  2. I would love to try it out if I had a place for it to be built. The rest is the easy part, as far as I'm concerned!

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