trailer made out of cardboard!!

budwich wrote:
yes... there is "no cell structure" like cardboard, the "1/4" inch thick panel is "full fibered" BUT if it gets wet, it likely loses its physical form and at the very least, usually appears to lose the contact surface / glue such that the top fiberglass sheet pulls away from the substrate.

I recently dealt with the issue on my Terry Dakota where the upper clearance light on the front top curve section leaked over time. It resulted in the seperation of the two layers. I "injected" in epoxy resin via the the side seam (taking off the metal corner bead) and also thru the clearance light cavity. Its not perfect but hopefully will hold although the integrity of the substrate is suspect as the glue interface surface is no long intact. Various videos on line provided the "guidance" or "directions". It was relatively easy to do a "triangular" shaped area about 1.5 feet at the top trailing down along the side for about 3 feet. I guess time will tell if I was successful. I am still considering what to do at the crest of the curve at the very top. The "substrate" there has dropped such that it doesn't support the curve shape. That is because at the top, behind the panel / filon is fiberglass insulation as opposed to foam and thus there is no solid sublayer (ie. the top panel was just curved / form around the cavity... the reason for the filon in the first place). I was thinking of injecting a bit of "low expansion foam" into the cavity but worry that it might not help since there isn't any solid "containment" in the area. I will likely leave well enough alone.