$220,000 Affordable Housing — 7 Comments

  1. Has LECA been investigated for earthbags? (Lightweight Expanded Ceramic Aggregate)

    I use LECA for growing orchids semi-hydroponically, and I know that it was originally a construction material (concrete additive, I believe), but I’m striking out on finding prices on large quantities. The porous quality should provide insulation value, and it should be more available where pumice/scoria have to be shipped long distances.

    • Someone asked about this a few months ago. Sorry, but I don’t have time to investigate every possibility. Buy some if the price looks really favorable and test it out.

      And please report back with your findings: cost, R-value, working properties, availability, etc.

    • A quick check reveals that LECA is highly absorptive. This would seem to eliminate it for use in earthbag walls unless someone can think of a way to prevent it from absorbing moisture.

  2. I really like the earthlodge cluster design. However, I would make one modification for cold climates. I would build a double-wall system, with the inner wall being earth/clay, and the outer wall being scoria or other insulating materials.

    I would make these two layers butt up against each other, and secure them with wide staples, made out of rebar, which will run from the center of the earth-filled bag to the center of the insulated bag, holding down the barbed wire on both bags at the same time. I would place these staples every 2-3 feet. This will not only hold the insulating layer tight against the more solid layer, it would increase the seismic stability, as Alaska is known for large earthquakes.

    I would then, before earth berming, put a layer of EPDM plastic over the outside of the wall to reduce or eliminate water intrusion. This should result in a home that requires very little heating and is structurally superior to the wooden houses being proposed. It would give both thermal mass that, once heated, would retain most of it’s heat, due to the insulating factor of the outer layer.

    Perhaps the perlite manufacturer, mentioned in the above link, would be interested in being involved?

    • That’s a good point about earthquakes in Alaska. I’d forgotten about that. The best way is to use Precision Structural Engineer, Inc. reinforced earthbag system. It’s all figured out, meets code and is engineer approved. Just add the layer of insulation and better roof. I was thinking wide TJIs instead of wood poles so there’s space for more insulation.

      EPDM is very expensive. I’ve good success with 6 mil poly. I think it could be layered with cardboard or something between for protection against punctures. But then again, if people there have $220,000 to blow on houses then it’s best to use EPDM or that waterproof spray foam even.

  3. I agree, $220K doesn’t sound very affordable, unless you enjoy being in debt for thirty years. Especially since it is only 900 sq. ft. That’s pretty minimalist.

    • Maybe we should create a cold climate design team and put together a proposal. I’m thinking something along the line of using the traditional earth lodge that’s upgraded for improved efficiency.

      Earth Lodge
      Earth Lodge Cluster

      Think about it. Native peoples have lived in extreme northern climes for thousands of years. They didn’t have spray foam insulation and all the other high-tech high-cost solutions, and yet they managed to survive. Why not modify those designs just slightly so as not to cause the price and complexity to skyrocket?

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