I need some advice. My wife had a pool installed several years ago and had a contractor firend of hers start putting a roof over it. The pool span was 20' and her friend recommended using 4x4's for the posts and run 20'2x4's for the beams mounted on a 2x6 as this was to be a slightly sloped roof capable of having solar panels on the top(1'/20' slope) Needless to say the 20' 2x4's were not strong enough to hold up any roofing and started to sag imidiately. I am left with a series of 4x4 posts and a pool that is covered 2/3 of the way with a partial sagging roof. I am looking for advice on how to strengthen the 4x4's so I can use 2x6's for beams as I calculate that the 2x6-s will support the weight of the solar panels. Any suggestions?