im repairing delamination on my TT. there is really no way of knowing how bad it is until you get in there.. if the outer fiberglass is delaminated from the core then more than likely the thin wood backing between the outer skin and foam core has rotted away. this was the case with mine. my only option was to remove all the damage and build a frame in the affected area from treated studs and then fill the openings back up with the apropriate thickness of rigid foam and adhesive. you also want to bond all the tems back together as well as possible using clamps and boards holding pressure on both sides until cured. mine doenst look perfect and still has some small ripples in the skin.. its really strong though