Damp Testing & Repair

Damp is the single most common — and most costly — problem affecting caravans and motorhomes. Because the bodies are built from bonded panels with many sealed joints, water ingress through a failing seal can spread unseen until it has rotted timber, delaminated walls or damaged the structure. Damp testing detects it early; damp repair puts it right.

What's included

Damp testing uses a calibrated moisture meter to take readings at numerous points around the vehicle — walls, floor, lockers, around windows and rooflights, and along seams. Readings are typically interpreted against an industry scale: under around 15% is considered dry/normal, roughly 15–20% is a caution range to monitor, and over about 20% indicates active damp needing attention. The engineer also inspects external seals and seams for the source of any ingress.

Damp repair depends on the severity and source:

• Re-sealing — replacing failed sealant around windows, seams, rooflights and panel joints. The most common and least costly repair.
• Panel or section repair — where ingress has damaged internal walls or floor, the affected section may need replacing.
• Full re-seam — on older vehicles with widespread seal failure, all external seams may be stripped and re-sealed.

Typical cost

Damp testing as a standalone check is relatively inexpensive — often £60 or so, or included within a habitation check. Repairs vary enormously: a localised re-seal might be modest, while major panel work or a full re-seam can run into four figures.

Frequency

As needed, but damp testing is part of every annual habitation check. Catching damp early, at the monitoring stage, is the key to avoiding expensive structural repairs later.

Why it matters

Untreated damp doesn't stay still — it spreads, rots structural timber, and destroys a vehicle's value and safety. It is also the leading reason caravans and motorhomes fail to sell or are written off. Early detection turns a potential four-figure repair into a simple re-seal.

DIY vs professional

Owners can and should watch for the warning signs between checks (see our damp guide), and consumer damp meters exist. But interpreting readings reliably, finding the true ingress source and carrying out durable repairs is specialist work — a botched re-seal often makes matters worse.

What to expect

Damp testing takes under an hour as part of a wider check. If active damp is found, a reputable engineer will identify the source before quoting for repair, rather than simply sealing over the symptom. Find a damp specialist in your area and request quotes.