Jeremy,
The only fiberglass in your wall is the outer layer. The inner layer is a plywood material with foam insulation filling in the voids between the metal frame work.
There are two problems that can commonly cause delamination of the walls in a coach. The first is caused by poor prep work (faulty workmanship) when the wall is fabricated. The other cause is when moisture in the wall causes failure of the bond between the outer skin and the frame work. Since the frame work in a RV wall is not sealed against moisture like a boat hull, because it would add weight and cost, water in the wall can cause real problems.
Gerald
