Campervan Damp Checks: Why Moisture Is a Van's Biggest Enemy

Ask any van technician what kills campervans and they won't say crash damage or engine failure — they'll say damp. Water that seeps into the timber frame causes rot that spreads silently behind cupboards and under floors, and it's one of the most common reasons vans are written off. Worse, many UK motorhome insurance policies specifically exclude gradual damp damage, so repair bills land entirely on you.

How damp gets in

Damp enters through failed seals around windows and roof lights, cracked roof seams, poorly sealed screw holes from an old aerial or solar panel, and worn door seals. Condensation from cooking and breathing adds to the problem, and once the water is inside the sealed walls it has nowhere to go.

How a damp check works

A professional damp check uses a moisture meter pressed against the interior skin. Readings are usually interpreted like this:

• 0-15% — dry, normal for a healthy van.
• 15-20% — suspect; keep an eye on it or investigate the nearby seal.
• 20%+ — wet; there is active water ingress and work needed.

A professional check costs around £60-£100 and covers the floor, walls, ceiling, window frames and roof lights. You can buy a basic moisture meter for about £30 and repeat the check yourself at home.

Where damp hides

The classic hiding spots are the corners behind kitchen units, the floor around wheel arches, under the bed, the front cab floor and around the windscreen pillars. These areas are covered by panelling, so damage can be far worse than it looks.

What to do if readings are high

If you already own the van, trace the leak before doing anything else — sealing a wet van in just stores the rot. If you're buying, treat a wet reading as a serious negotiating point or walk away; a damp repair can run to £1,000+ once timber is involved, and often far more.

Tip: a van that smells musty when you open the door has probably been damp for a while. Trust your nose, then verify with a meter.

Damp is checked as part of a full motorhome habitation check, so if you're serious about buying, arrange one before you commit. And to compare vans that have been cared for, browse motorhomes for sale.