Gravel bag foundations save thousands of dollars, use no concrete and don’t wick water up in the wall.

Gravel bag foundations save thousands of dollars, use no concrete and don’t wick water up in the wall.


“There will be many who refuse to believe this will work. What no concrete? Will be their never-ending refrain.

Concrete foundations have been around for less than a hundred years. Buildings have been built for millennia. In the eastern Mediterranean it’s common to see structures still standing over 2000 years after they were built, without a drop of concrete.

Concrete is not just un-eco (the carbon footprint for producing the stuff is massive). It also has a habit of wicking up water. This is bad news for an earthbag house.

I spent a few sleepless nights over this gravel foundation. Now I’m as pleased as punch with it. If you live in an area that experiences a lot of rainfall nothing beats it. For the doubters, my house has withstood a 6.1 earthquake, and is bone dry.

Here’s how to do it.

1. Dig a trench half a metre deep. Make sure the trench is wider than the earthbags.

2. Fill the trench with rocks from the surrounding area up to about 20 cm below grade.”

More at the source: The Mud Home
Here’s another good page from this site: Building for Free


Comments

The Mud Home: Earthbag Foundations — 4 Comments

  1. I’m with you on concrete. There is a women who built a large straw bale home in Tuscon and i was amazed at the requirements she had to go through. If i remember right she had to have a huge stem wall built from concrete to meet codes.It sounded very pricey and i don’t see this as being really green. Once more it comes down to building codes.

    • Right. She was probably required to build a foundation the thickness of the bales. That’s why I often recommend a post and beam frame with straw bale infill. That way a typical 8″ foundation will meet code.

      • Owen, I have had a thought on a few occasions that relates to this article and your comment. Would there be an advantage for achieving code compliance and avoiding the moisture-wicking problems of concrete by simply burying the foundation below ground level and placing an additional layer of gravel over top at grade? I hope that this is not a dumb question… :-S

        • That would work, although there’s no guarantee the building inspectors would approve it. Most likely you’d need an engineer’s stamp of approval.

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