Straw bale compression – finishing off the walls at Castle Hill School
The walls are up at Castle Hill School, and we’re preparing to add the roof.
Meanwhile work has been continuing at a pace. We’ve had a mixed bag with the weather – plenty of swelteringly hot July days, but some rainy ones too, forcing us to cover up the walls with tarpaulins. Rain and straw do not mix!
Here’s Rachel adding the very last straw bale:
Once the walls are complete, the straw bale compression can begin. Firstly by tightening up the ratchet straps which have been placed at near intervals all around the walls:
As the straps are tightened, the straw walls compress, making a firm and solid base for the roof. There’s a real art to this process – the building designs state the precise height of the walls, so if the straw bales compress any more or less than expected, the wall height will not align with the building designs.
It turned out that our walls were the right height before compression, leaving us with a problem. But one of the wonderful things about straw is its flexibility – we were able to make up the shortfall with extra straw, so that after compression, the walls were the perfect height.
And we’re still on schedule. The walls have been compressed, the wall plate is now in place and we’ll be adding the roof this week!