How to Spot Water Damage in a Used RV

Get inside before anyone opens a window.

Musty is the whole answer. A closed-up trailer that smells like a damp basement has wet wood in it somewhere, and no amount of air freshener changes what is behind the panel. If it smells clean and dry after sitting shut, that is real information too.

Be suspicious of a trailer that was aired out before you got there, or one that smells strongly of cleaner.

Water almost never comes through the middle of a roof. It comes in at the edges of things.

1. Roof penetrations. Every vent, fan, antenna, skylight, and solar mount is a hole in the roof that is only closed by sealant.
2. The front and rear caps. Where the roof membrane meets the front and back of the trailer, the joint moves every time you tow.
3. Windows and doors. The sealant behind the frame dries out and shrinks.
4. Marker lights and any screw through the sidewall. Every one of them is a hole.
5. Slide seals. The seals around a slide-out harden and stop touching.
6. The underbelly. A torn or sagging underbelly lets road spray in from below, and that damage rots the floor from the side you cannot see.

When you look at a trailer, look at those six things and skip the countertops.

Stand at the front corner and sight down the sidewall with the light raking across it.

A good wall is flat and boring. A wall that has taken water is wavy, or has a bubble, or has a soft patch that gives when you push. That is delamination: the outer skin has come unglued from what is behind it because water got between them.

Small and high on the wall is one story. Large, low, and near the floor is a different one, because that means it has been running down inside.

Walk the floor in socks. Heel first, whole weight.

Press just inside the door, around the toilet, at the shower, under both sinks, at the foot of the bed, and along the front edge of every slide. Flex, give, or a hollow sound means the top layer of the floor has separated from what is under it.

Then press the walls with the flat of your hand near the front cap, near the rear cap, and under every window. Firm everywhere is what you want.

Look up. Ceiling corners, the top edge of every window, the seam where the ceiling panel meets the wall, and the inside of every overhead cabinet.

Brown lines and rings are old water. A wrinkle or a sag in the ceiling panel is water that got in and sat. Fresh, dark, and damp to the touch is water that is still coming in right now.

Open every cabinet and look at the back corner of it, and look at the underside of the mattress and the bottom of every drawer. Nobody repaints those.

A moisture meter costs less than a tank of fuel, and it turns the whole conversation from opinion into a number.

Read a wall you know is dry first so you have a baseline for that trailer, then read the suspect areas. A reading that jumps in one corner and nowhere else tells you exactly where to look next.

Not all water damage ends a trailer.

A leak that was caught early, dried out, and resealed, with no soft floor and no delamination, is a maintenance item and a bargaining chip.

What gets expensive fast is anything structural. Soft floor across a large area, a rotted wall frame behind the delamination, or a rear cap that has separated is a rebuild, and on an older trailer the repair can cost more than the trailer is worth.

The honest answer is that you cannot tell which one you are looking at from the parking lot. Somebody has to open it up.

RepairAnyRV, our sister shop, is at the same Princeton address as our lot, and water damage and roof and seal work are what they do. If you are looking at a trailer and want a second opinion before you commit, call them and ask about having it looked at.

Every unit on our lot is inspected before it lists, roof, seals and floors included, and what we find goes in the listing.

Browse the inventory, and read the rest of the walk-around checklist while you are at it.