The side boards on my roof are rotten. I had thought about taking the roof apart and repairing it. However, the more I think about it, I would like to completely rebuild it. Is there any reason I shouldn't build a completely new roof out of plywood and Fiberglass? I would like to add a couple inches of headroom. I'm 6'5" and my hair just hits the ceiling now and I bump the A/C. My thoughts on construction are 1/2" plywood sides with 3/4" plywood rafters @2' centers with a 1/4" top skin covered with fiberglass. Everything would have a slight arc to it for drainage and I would build in a small curb for the A/C to help prevent leaks. I know this would be considerably stronger than the original roof. I would also include insulation and probably an FRP board interior ceiling. Will this add too much weight for the lift system? Are there any other drawbacks to consider? Thanks in advance for your advice.