And yes, it was cold yesterday...
So, why again the earthbags? Well, they do two things: provide a flat surface to put the wooden part of the wall on (the wood wouldn't sit very well straight on the rubble), and they separate the wood from the ground, which should prevent moisture issues.
Here's a photo of the first course of earthbags after wetting them with a hose and tamping them flat:
The contractors plastic under them will wrap up around the sides to truely separate the bags from any water coming from below. Its pretty thick plastic either 6 or 8 mil, I think. Also, it doesn't matter too much whether the earthbags align absolutly perfectly - I placed them so that the extended about 2 inches outside the string lines, and will get the building perfectly square when I put the 2x6 plates down.
After tamping the first course flat, I went around with a piece of 2x2 and made dimples in each of the bags. When I tamp the second course of bags, the top layer will fill the dimples and help lock the bags in place. Each dimple was about 1-1.5 inches deep. Here's a photo:
Here's a photo of the first course with some of the untamped second course sitting on top. I put the second course down in running bond (staggering the joints), and you can see that I've wrapped the inside plastic up and pinned it to the first course with nails:
I'll get a photo or two of the completed second course and add it here later, but for now thats all.
2 comments:
One concern I have about what you have done for this foundation is that by wrapping the damp soil with plastic it will have a hard time drying out, and may never dry out if the top is sealed. This, combined with the fact that the bags are burlap and will decay over time, might present some problems in the future with possible slumping of the soil. It might be best to allow the soil in the bags to thoroughly dry before you wrap them with the plastic. While the plastic will keep water from being absorbed into the bags, it will also retain any moisture that does find its way inside, so this presents another challenge in keeping the bags dry over time. I am generally in favor of keeping walls breathable whenever possible, to avoid these kinds of problems.
The plastic between the first course of bags and the rubble trench is probably a good idea in your case, since the crushed volcanic rock that you used can actually wick water to some extent, and this will keep that moisture from wicking all the way into your wall.
I saw your post on CountryPlans -- great blog.
I agree with what Kelly says -- the barrier between the trench and the earthbags makes sense but wrapping them doesn't. Instead why don't you tie the poly to the walls 2-3 feet over the foundation and let it drap over the earthbags? (make sure you cover it with gravel on the outside to prevent UV decay)
I read a great building quote -- I think it was from the CountryPlans forum -- "think like water".
- Doug Martin
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