Damp Check: What it means and why it matters
A damp check uses a moisture meter to test caravan and motorhome walls, floor, and roof for water ingress. It is the single most important pre-purchase inspection on any used leisure vehicle and should be a non-negotiable for every used buyer.
Water ingress is the biggest enemy of a caravan or motorhome. It gets in through failed sealant, cracked or stressed body seams, window and rooflight frames, awning rails, and door surrounds. Once inside, water rots the timber frame, can cause delamination where the inner wall separates from the structure, and creates mould. A proper damp check uses a calibrated moisture meter taken systematically across every wall, the floor, and the roof, with readings recorded against a body diagram. Dealer damp checks are often quick and free, while independent inspections through schemes such as the NCC Approved Workshop Scheme are more thorough and typically cost from £50 to £150.
Why this matters
Damp damage often costs £2,000 to £5,000 or more to repair properly, and severe cases can write a caravan off completely. Buying a used caravan or motorhome without a recent, dated damp report is one of the highest risk decisions a buyer can make.
Common misunderstandings
- A clean interior does not mean a dry caravan. Damp usually hides inside the wall structure, not on the surface
- A damp check is not the same as a habitation check, although a habitation service normally includes damp readings
- Last year's damp report is not enough. Damp can develop quickly, so always ask for a current report dated within the last few months
Example
Common warning signs to look for: soft or spongy areas around windows and rooflights, dark staining at the bottom of walls, a musty smell when you first open the door after storage, bubbled or lifting wallpaper, and rust marks around fixings. Any of these justifies asking for a fresh independent damp report before you commit.
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Frequently Asked Questions
A basic dealer damp check is often included free with used stock. An independent professional inspection through an NCC Approved Workshop typically costs £50 to £150.
At least once a year, ideally in autumn before winter storage. Also any time you buy a used caravan or motorhome, and after any long period of storage.
Industry guidance generally treats readings under 15 percent as low risk, 15 to 20 percent as a watch area, and above 20 percent as high risk needing investigation. Always get a qualified inspector to interpret readings in context.