I knew I wanted to insulate the Carabane with sheep's wool. It is non-toxic, renewable, has good thermal and acoustic insulation properties, and it regulates humidity. One website quipped 'Wool is terrific insulation: ask any sheep.' It makes me think of the sheep I saw in Iceland in October- the snow on their backs didn't even melt because none of their body heat was escaping! And as we know from merino clothes, it is warm and it breathes. This is just as important for walls and roofs as it is for shirts. If the humidity in the air is above 65%, wool will absorb moisture, and if it is below, it will release it. Moisture control is a key issue in construction (interiors tend to be hot and damp while exteriors cold and dry, resulting in the migration of moisture through walls and roofs). So the key is finding materials that allow for the free movement of this vapour, in order to prevent mold and mildew building up inside the walls.
After searching for a while I found the Swiss company Fiwo that makes batts out of wool fibre. In a lot of cases, freshly sheared wool is simply thrown away because it's not worth the trouble of cleaning or sorting it. So I was glad to find this company that buys raw wool off Swiss farmers.
In my post on the double beams I explained that I was going to fill the space between with insulation. With the help of a friend, we stuffed the space with batts. I have an insulation knife that makes quick work of cutting them to the right shape. And it is such a pleasure to work with wool- it feels nice on the hands. Nothing like the itchy fibreglas batts that are often used in Canadian house construction.