Week 21, Day 2 Posted on 2016-03-08 by dMb Reply Week 21, Day 2: Starting to round out the curved section of roof The SIPS panels are planar and form a series of facets rather than a true curve The finished curve is formed using 3 layers of 6mm plywood, glued together Week 21, Day 2 Starting to install the first layer of 6mm plywood on the curved section of the roof