Seals and leaks

A guided diagnosis for RV techs. Each step is a check, a reading or a question.

Where is the water showing up? Water travels. Where you see it is rarely where it comes in. Expect: Dry readings on a moisture meter; sealant intact with no cracks or lifted edges

Causes and repairs

Roof penetration

Vents, AC gasket, antenna, skylight, the front and rear cap seams, and every screw in the roof. Water runs along the ceiling framing before it drips.

Tools: hose, helper, moisture meter

Inspect every penetration above and ahead of the stain. Water test with a hose section by section, inside with a helper. Reseal with the correct sealant for the roof material (self-leveling on flat, non-sag on vertical). Replace an AC gasket that leaks in rain.

Window or door seal

Putty tape behind the frame dries and cracks. Weep holes clog and the track overflows inside. Door seals compress.

Tools: hose, sealant

Clear the weep holes. Reseal the top and sides of the frame with non-sag sealant. Reset the window with new butyl if the frame leaks behind it. Adjust the door strike.

Floor damage

Water from a slide seal, a plumbing leak, a door, or the belly. Find the source before the repair or it comes back.

Tools: moisture meter

Moisture meter the perimeter to map it. Open the belly if needed. Fix the entry point, dry it, then repair the floor.

Delamination

Water got between the fiberglass and the luan, or the adhesive let go. A soft bubble that moves. Mark its edges and the date.

Tools: marker, moisture meter

Find and stop the water entry (usually a seam or molding above). Inject epoxy and clamp small areas. Large areas are a wall rebuild. Document it for the owner.

Slide seals

Wiper seals folded under, bulb seals torn or flattened, or a slide topper that pools. Water comes in at the floor edge when extended.

Tools: seal conditioner, hand tools

Inspect and re-seat the wiper seals, replace torn bulb seals, condition the rubber. Adjust the room if it isn't sealing evenly.