Wednesday, July 6, 2011

Straw clay

Back in Homer

Straw clay is a natural building material used as insulation in timber frame structures. Its use apparently dates back to 12th Century Germany, and it has made a major come back as a material of choice in the natural building movement that has picked up steam in the last few decades. The advantages to working with this kind of material include: 1) it is widely available and inexpensive, a good clay source is frequently available onsite or close by; 2) it is an environmentally sound choice, one of whose process the builder can be fully aware, involving small-scale, minimally disruptive extraction, no chemical industrial processing, and it's not going to contaminate your work site; 3) on that last note, whereas conventional building materials are often highly toxic and have been associated with numerous health issues, you can rely on straw and clay to not poison your kids.

Clay of all colors and textures. Got to test these to see if their clay content is sufficient.

One test is to form a worm and see how far you can bend it without breaking. If it can form a ring like this it's a good sign.

Mixing the slip (clay sand and water). The proportion is key,
and particular to the clay you're working with.

Separating the slip from the clay balls that form in the mixer

Testing the viscosity of the slip to see if we got the mix right.

Some refreshment around the fire in the evening. Songs to be sung.

Mixing the slip with straw

Nailing in the lath. This formation will hold the straw clay in place while giving it enough air to breath and dry out over the course of the coming months.

Every surface with which the straw clay will be in contact must be wet before hand, which will allow it to form a bond and adhere properly.

For some applications it makes more sense to form the straw clay into bricks, like so. In such a case it's necessary to chop the straw into much smaller segments. In this case we are actually experimenting with pushki (Alaskan cow parsnip), a local material that has desirable traits for our purposes (light weight, porous, i.e. can trap a lot of air without adding weight).


The results are good.

Meals were prepared by a few folks from the community, so we ate gloriously for the three days we were at the workshop. Bottomless thanks to them, as ever.

Tired chef's feet

1 comment:

  1. i so very wish i was building things with soil right now.