Monday, 14 November 2011

Strawbale Chookhouse

Why a chookhouse
Well why not. Chooks lay better if kept warm in winter and a strawbale house will do that well. And it gave us a chance to learn the basic techniques on a small scale.
The bales and roof are on at the end of the first weekend.
Wall rendering still to come of course.  

Why Strawbale
Strawbales are cheap and locally available and provide incredible insulation. Their resistance to heat transfer is around R10, which geeks will recognise iss a high value. They will keep you cool in summer and warm in winter. The walls will be sealed with render to stop the straw decaying and make it rain proof and fire proof for 3 hours, but the render will enable the wall to breathe too. The low level of moisture in the dry straw of a new wall, will mostly, slowly, be expired.

Even better, in the distant future if you want to knock the building down, the raw materials are not hazardous and can be reused or left onsite.

An octagonal concrete slab was built 3-4 weeks prior to construction. On top of that, a loose gravel base contained with a wood frame around the edge of the slab. Bales, placed on top, were mostly bent and occasionally cut to fit the octagonal wall shape 2 bales high. Planks cut to fit were placed on top of the bales which were then strapped with wire vertically and horizonally through the wall. The wire was tied together with gripples which compressed the bales to no more than 10%. This makes a surprisingly solid wall. We repeat this with two more layers of bales and then put on a wooden A-frame roof which we also build from spare materials on site.

Next week we will render the walls and finish the roof and trimmings and I will update you then.

Where is this Chookhouse?
We built this chookhouse at Bandusia Country Retreat at Upper Macdonald / St Albans, where Penny Peytt and Frank Thomas ran a workshop on this topic.