I have built plenty and many of all sizes. The best one we have is only about 5 feet off the ground on 4X4 posts. We got plywood and had someone sitting in the bench seat we built. Also, had a guy on the ground pushing the plywood up or down to the perfect height. Height of seat is also very important and is also overlooked. If that thing is uncomfortable, you cant sit in it very long. You want these things for an all day sit through a rainy day. For the roof, we had access to big pieces of rubber. that and roofing nails on top of the plywood has worked great. Good luck with it.