RV Roof Soft Spots: What They Usually Mean

A soft spot on an RV roof usually means the wood under the membrane is wet, and it won’t dry out on its own. Most owners who feel one press it a few times, decide it’s “probably fine,” and climb down. Here’s what that spot is telling you, and what to do about it.

What causes a soft spot on an RV roof?

Wet decking. The rubber membrane you’re standing on is thin and has no strength of its own. It’s glued to a thin sheet of plywood or luan. When that sheet gets wet, its layers come apart and it goes soft, like damp cardboard. The membrane on top can look perfect. The water usually got in sideways, from a seam or a vent nearby.

How do you tell normal roof flex from a soft spot?

Lightweight builds flex a little between framing members, and a hot day makes every roof feel softer. So compare: walk the same spot on the opposite side of the roof. Even give on both sides is how the roof was built. A spot that feels mushy, crackles faintly, or stays dented for a moment after you step off isn’t. Neither is one that feels clearly different from the rest of the roof.

What happens if you ignore a soft spot on an RV roof?

It spreads. Wet decking doesn’t dry out down there. The membrane seals it from above, the vapour barrier slows it from below, and the insulation beside it holds water like a sponge. Rot spreads under perfectly good rubber, and every step flexes the weak sheet a bit further. Each winter’s freeze-thaw pries the layers further apart. A soft patch the size of a dinner plate in June can grow to a quarter of the roof by the time it shows inside.

Why does a soft spot cost more the longer you wait?

Replacing decking means opening the roof: membrane up, bad wood out, new decking in, then proper sealing over the repair. The cost grows with the area. A one-sheet repair caught early is a manageable job. The same rot two seasons later can involve framing, insulation, the ceiling panel below, and a harder conversation about whether repair still beats replacement.

How is a soft spot on an RV roof assessed?

Not with a thumb-press and a shrug. We take moisture-meter readings to map how far the wet goes, because it’s usually bigger than the soft area. We check the nearest seams and penetrations for the entry point, look inside for staining and smell, and photograph all of it. Then you get options in order: fix the leak, repair the structure, reseal to protect the repair. Sealing over wet wood is the one move that’s always wrong. It just locks the problem in where you can’t see it work.