Fifth wheel sidewall delamination traced to a window that was never bedded

Delamination is the repair owners most often get talked out of, because the surface fix is cheap and the honest fix is not. Two shops had told this owner the ripple was cosmetic. It was not cosmetic; it was a bond line that had already released across roughly thirty square feet, and a laminated sidewall carries structural load through that bond. OCRV Center put a moisture meter on the wall in a grid pattern before saying anything, because a map is an argument and an opinion is not.

The map pointed at the bedroom window, and the window told the rest of the story. When the flange came off, the original butyl bed had squeezed out and thinned to nothing along the lower edge, leaving a track where water had been running down inside the wall for what was probably several seasons. Nothing about the exterior gave it away. The Filon skin was intact, the sealant looked serviceable and the interior wallboard showed no stain at all, which is why owners keep hearing that it is cosmetic.

Peeling the skin back is the only way to find the real boundary. At OCRV Center the rule is to stop peeling when the adhesive tears the core rather than releasing cleanly, and on this trailer that point sat about two feet outside the chalk line drawn from tap testing. The wet block foam came out, the cavity was dried to a stable moisture reading across two days rather than a single afternoon, and replacement foam was fitted in the same thickness so the wall finished flush.

Re-lamination is where a shop repair either matches the factory or does not. The panel was pressed under vacuum with the shop climate held steady through cure, which reproduces what the original press table did and produces a bond line without dry spots. Releasing pressure early is the shortcut that turns a fifty hour repair into a repeat visit eighteen months later, and it is not an option on a wall that has to carry load for the rest of the trailer's life.

The visible half of the job is fairing and refinishing. Filon arrives flat and shows every imperfection in the substrate behind it, so the skin was faired, primer surfaced and block sanded until reflected light ran straight down the length of the wall. The body decal scheme was reprinted to match the surviving graphics, and the window went back on fresh butyl tape with the fasteners torqued in sequence rather than driven home in one pass.

This one was paid by the owner rather than a carrier, which is the usual outcome on delamination. Most policies treat gradual water intrusion as maintenance rather than a sudden loss, and there was no event to point at. OCRV Center wrote the estimate against the published delamination band so the owner could see the hour range before committing, and the final invoice landed inside it. The trailer left with a documented photograph file covering every stage of the wall.