I bought a fifth wheel and noticed some rippling in the rear garage area on the wall. I could tell the wood was soft behind it and decided to rip into the wall this weekend. The interior panel with the vinyl on it was trash. I have no concern about replacing that but I do have some concern about the integrity of the panel on the exterior. After I got the interior panel off there was insulation and metal studs. Behind the metal studs was a few layers of thin wood followed by the exterior gel coat material. The thin layers attached to the exterior were rotting and I scrapped it off until I got to good dry wood. I am now concerned about my next step. Do I need to take the entire metal wall out and bond a new piece of wood against the exterior. I have rebuilt houses, cars, boats, etc but if i am getting on over my head I'm looking for someone to tell me. I have checked the rest of the trailer and found one more soft spot on the same wall a little further back. The good news it this trailer was stored in doors until about 6 months ago (i know the guy that owned it before) so I believe most of the wood rot was newer. The insulation was actually still wet on the inside. I have had it in my shop with a carpet dryer on it for about a week now.