The roof plate was held up with folding wedges, to hold it higher than the finished height of the wall. This was to allow room to manoeuvre the bales into position and to allow for compression. Once the walls where built and the roof was ready to be dropped, the wedges could be knocked out, allowing the roof plate to drop down steadily.
All 8 sets of wedges where knocked out simultaneously, to lower the roof in a controlled and even fashion. Our bales compressed circa 10-15mm per bale, which accounts to 60-90mm for the whole wall.
The weight of the roof alone will do a lot of the compression of the walls, but we wanted to speed this process up and make sure the whole roof plate was level. This was done with a number of ratchet straps and our trusty water level. With the ratchets wrapped around our roof plate and our box beam, we where able to make adjustment to ensure the roof plate was level around the whole building. The roof plate was then fixed into position with screws into the window / door posts.