Patti Stouter’s Straw Wattle Dormitories — 14 Comments

  1. Owen wants my photo of a recent straw wattle vault compression test. Yes, cheaper materials are needed for roofing. And straw clay is a possibility. But just like earthbag, the waterproofing is critical.
    Cement (even half cement half lime) is too liable to crack on earth and earth/straw structures. Any water going into straw wattle would be a mess- mold contaminating the interior air, loss of strength, ultimate collapse.
    My best idea for waterproofing a straw wattle vault would be to use Magnesium based cement like Grancrete. But the Grancrete is expensive. I wonder about leaving ties coming through the filling plaster, tying on a thin cotton fabric, and painting that with the Grancrete.

    A straw clay vault without wattle might be easier- packed into forms. I’d leave ties through it and snugly tie it to plastic bird netting or heavier mesh inside and out, then plaster. But the waterproofing is critical!

    I am testing trash wattle vaults right now, that can be covered with cement. Let us know if anyone is trying any vaults!

  2. Roof leaks will dampen walls and attract termites. But if the building owners/ occupants are careful to have a good roof overhang and keep the roof in good repair, then termites are much less likely to invade the wall.
    I loved Owen’s test a while back where he took a dried bag of straw clay, covered the top from the rain, and put it on top of a termite mound. Because the termites had other material to eat, they ignored his dry straw and earth block.
    Yes, we can’t be sure that termites in the intense damage areas will ignore straw walls. Planting vetiver along the base of the walls will help. Using vetiver grass or vetiver root is even better.
    Lime is naturally insect repellant because of it’s high ph. One could also add borax to the clay as an insecticide, but borax is very toxic to any plant life and will not be good composted in future. Perhaps a borax soaked first straw wattle course would be helpful to deter any termites coming through from the earthbag layers.

  3. This is very inspirational and gives hope to those who really need it. Thank you Patty. People like you and Owen prove there’s still honorable people out there. We need more people of honor today. More than ever.

  4. How about lime . The grasses ? Say buts don’t like. At Auroville in India architect there told me that termites even munch cement. Why not domes, to take care of roofs?

  5. Thanks Owen.

    I guess a lime/clay plaster will keep the termites at bay. Can you confirm that?

    Also, Vetiver is in short supply here (I am growing my own for thatch for your roundhouses), is there any other grass which is suitable? I have looked at using/incorporating dried pyrethrum stems but the main grower in Kenya tells me that there is next to no pyrethrin left in the stalks. We could always use pyrethrin insecticide in the clay slip and it is classed as organic but it doesn’t quite sound “natural” to me.

  6. Patti Stouter rocks! I can’t wait to try straw wattles. I have vetiver grass in my garden and am interested in using it in wattles/bricks/earthbags. One problem I have is that it has no tensile strength at all. The leaves seem to be fragile. I understood that the straw or rice husks used in earthen building were for tensile strength.

    • You only need tensile strength when it’s in plaster, and for that you only need a minuscule amount. Vetiver should work fine for everything we’re discussing if used correctly. Just keep in mind these ideas are for emergency shelters in developing countries.

  7. Hi Patti and Owen

    I live in humid tropical Kenya where there are a variety of straws available including Vetiver.

    I would like to try a similar building method for certain ancillary buildings such as stores and laundry area etc but am worried about termites in the straw.

    Do you have any eco-friendly suggestions?

    • Our site is suddenly working! Wow. That’s the first time in two days.

      Vetiver grass is naturally insect and water resistant. It should work fine, especially if covered with a durable plaster (not earth plaster because the insects might get through and cause problems).

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