Smithder wrote:
Many RV manufacturers construct the side walls as a sandwich of materials. The outside is a thin layer of fiberglass, bonded to a 1/4" layer of plywood, which is bonded to a 1" or so thick layer of Styrofoam, bonded to an inner layer of 1/4" plywood and last a layer of decorative vinyl wallpaper. The problem with this construction is that once the plywood gets wet from a leak, it essentially never dries out. The fiberglass, Styrofoam and vinyl wallpaper don't allow the water to evaporate and evaporation that can occur from just the end edge of the plywood is very slow. Over time the plywood that stays wet rots and loses its bond with the adjacent layers, resulting in the dreaded delamination.
Looking at your picture, I can see a vertical line of delamination in the middle and a horizontal line of worse delamination about halfway down the side wall with a good sized bubble near the entry door. There also appears to be another horizontal line of delamination near the top in the awning shadow. These lines are the butt joints of the plywood panels that made up the outer wall. It appears that at some time in the past there was a water leak that traveled down the vertical butt joint and then spread out along the horizontal joint. Whether or not the leak was repaired, the water was trapped in the middle of the wall and rotted the wood.
It's only going to get worse with time.
