We spent the weekend playing with mud. Cob is a mix of clay, sand and straw, you mix it up till its the gloopy stuff in the world, then just squish it onto a wall. It dries, you put a roof on it to keep it dry, and that’s it.
Its pretty much the lowest environmental cost building material that you can have, so we’re going to have some of it. Probably only internal walls only though, coz it don’t work too well with Wellington’s horizontal rain. Makes for lovely soft-looking hand-sculpted walls, lots of thermal mass to hold the heat.
The soil on our site isn’t perfect, far too clayy, but there’s a quarry 2 km down the road, so haulage won’t use too much diesel. We like.