I once looked at a sunroom that had loose aluminum trim, the nails were all walking out. When I pulled the trim off, the double 2x10 header was fine over the door in the center but it was eaten almost completely away by the ends eight feet away on either side. Almost 20 feet of roof was precariously balanced on a 40" header in the center, and the ants were still active. I think it's worth a look.