Hidden Water Damage in a 26 ft Travel Trailer Bought Used

A 2016 26 foot single slide travel trailer, one owner before him, stored outdoors in inland Orange County for most of its life. Clean interior, good tires, working appliances, and one soft area about 14 inches by 20 inches on the floor just inside the entry door. The seller described it as a known small leak at the door that had been resealed. That description was honest as far as it went. It was also based on the same assumption the buyer made, which is that the stain marks the leak.

Nothing about the walk through was negligent. You cannot see inside a wall cavity, and a floor that flexes in one spot genuinely does feel like a localized problem. What would have caught it is a pre purchase inspection with a moisture meter, which on a trailer this size runs $400 to $1,200 and would have been about $650 here. That is the cheapest $650 available in the used RV market, and it is the single piece of advice we give most often.

Surveying ran days 2 and 3. We laid out a grid across the floor and the lower walls at roughly 12 inch spacing, 168 points in total, and recorded a pin type meter reading at each one on a plan drawing rather than calling out numbers verbally. Anything above 16 percent moisture content got flagged. Then we ran a thermal survey with the interior warmed and the exterior cooler, which makes wet material read as a cold mass because water carries heat differently than dry wood and foam.

The two methods disagree in useful ways. The meter tells you moisture content at a point, and thermal imaging shows you the shape of the wet area between points. Together they draw a boundary. After that we hose tested the exterior in stages, isolating one penetration at a time with the interior open, which is how the actual entry points get found rather than guessed. That sequence took a day and a half and it changed the scope of the job substantially.

The visible stain was about two square feet. The wet zone was roughly 41 square feet of floor decking running from the entry door forward past the wheel well and inboard to the shower pan, plus about 11 linear feet of lower sidewall bottom plate on the door side. Two floor crossmembers were rotted through at their outboard ends, three outriggers had surface rot with section loss on one, and the lower 6 inches of the sidewall interior paneling was delaminating from the framing.

Neither entry point was the door. The first was the fresh water fill flange, where the sealant bead had cracked at the top edge and let water run behind the flange and straight down the inside of the wall. The second was the awning rail about 6 feet up, where two fastener heads had backed out and the bead had let go. Water entered high, ran down the framing, spread along the bottom plate and pooled at the floor decking, then surfaced at the doorway.

Interior teardown and floor work ran days 6 through 20. The dinette, part of the galley base, the entry step assembly and the shower surround came out. Flooring and the wet decking were removed back to sound material with a straight cut over a crossmember, not feathered into a wet edge. The two rotted crossmembers were cut out and replaced in matching section, the outrigger with section loss was replaced, and the remaining framing was dried down with fans and monitored until readings sat under 12 percent.

Sidewall and closeout work ran days 18 through 28. The 11 foot bottom plate section was replaced, the lower interior paneling was replaced and rebonded, new decking went in with adhesive and mechanical fastening, and the belly wrap was replaced rather than taped back. Then the fill flange and the awning rail were both properly reflashed and rebedded, along with every other penetration on that wall, because a wall we have opened once should not need opening again over a $12 bead.

The invoice was $16,341: 46 body hours, 9 refinish hours for the lower skin section and belly, 3 mechanical hours for the water system and step reinstall, 4 detail hours, and $2,600 in parts and material at sell price. No insurance was involved and we told the owner why on day 3. The cause was gradual sealant failure that predated his ownership, which nearly every policy treats as maintenance, and we would rather say that plainly than help someone file a claim that goes nowhere.

Thirty four days start to finish, and the only real delay was the dry down window, which we do not shorten because closing a wall over damp framing simply restarts the clock. Prevention here was genuinely trivial. A seal inspection with reseal of failing penetrations runs $400 to $2,500 as annual maintenance, and this trailer needed roughly $200 of that work in 2019. Instead it spent five years quietly wetting its own floor structure.

Body and paint labor is posted at $210 per hour. Mechanical and electrical is $260 per hour. Diagnostics run $285 per hour with a one hour minimum that is credited back against an authorized repair. Ranges below reflect jobs we have actually completed.