Caravan damp checks that actually mean something

The Reality of Caravan Damp in 2026

Damp remains the single biggest threat to a caravan's longevity and resale value. As manufacturing techniques evolve—moving from traditional timber frames to composite structures like Bailey's Alu-Tech, Swift's SMART construction, or Elddis's SoLiD Bonded system—so do the ways water finds its way into the structure. Whether you are browsing used caravans or inspecting a private sale, a damp meter is a vital tool—but only if you treat it as a clue, not a final verdict.

Where Damp Hides (Even After a Valet)

Sellers will often clean and air out a van before a viewing. To find the truth, you need to look where the sponge doesn't reach:

• Front Corners & Window Sills: Check right into the corners under the front windows. This is a common fail point for older Bailey Pegasus Milan or Swift Challenger models if the window rubbers have perished or the front GRP/ABS panel has developed stress cracks. Browse Caravan Models to see common panel designs.
• Rooflights & Vents: Look for 'tide marks' on the ceiling panels immediately surrounding the frames. Even a premium Bailey Unicorn Cartagena can suffer if a seal was disturbed during a DIY solar install or if the sealant has degraded over time.
• Rear Panel & Awning Rails: The awning rail is a long, vulnerable seam. Check the internal wallboard directly opposite the rail for any softening or discolouration. Pay close attention to the Swift Basecamp Plus or similar models with unique rear door configurations where seals are under constant use.
• Washroom Thresholds: Inspect the floor edges and shower tray surrounds. Water often tracks under the vinyl flooring, rotting the ply from the inside out. This is critical in high-end models like the Buccaneer Aruba where wet-room designs are common.
• External Lockers: Battery boxes and wet lockers are prone to seal failure. Open them and check the inner wallboard for 'pimpling'—a classic sign of water trapped behind the vinyl.

What Damp Readings Actually Mean

In the UK climate, a 'zero' reading is rare due to ambient humidity. Understanding the scale used by the NCC and AWS is essential for an accurate assessment:

Reading (%)	Status	Action Required
0-15%	Dry	Normal; no action needed.
15-20%	Borderline	Monitor; re-check in 3 months.
20-25%	Moisture Present	Investigation and remedial work required.
Over 25%	Significant Ingress	Structural damage likely; professional repair essential.

Note: A single spike might be a 'cold bridge' (where a metal screw conducts cold and causes condensation). A pattern of high readings following a joint or seam tells a story of active ingress.

The 'Unglamorous' Tests That Save Thousands

1. The Sniff Test: Open every cupboard and locker, particularly those at floor level. They should smell of wood and fabric. A sweet, musty, or 'mushroomy' scent is a definitive warning sign.
2. The Press Test: Use your thumb to gently press the wallboard, especially near floor level and corners. It should be firm. Any 'give' or 'sponginess' suggests the timber frame behind has softened.
3. The Paper Test: Run a piece of white kitchen roll along window seals and rooflight trims. Any brown or orange staining on the paper indicates old or active water leaks.
4. The Floor 'Bounce': Walk heavily near the kitchen and doorway. Excessive flexing often indicates delamination. Check our Caravan Layouts Guide to see how different floorplans might distribute weight differently.

Professional Verification & Warranties

If you are investing significantly in a premium model like a Coachman Laser 665 or a Coachman VIP Vogue 575, do not skip a professional pre-purchase inspection. An AWS-approved technician has the calibrated equipment (often ultrasonic or pinless meters) to find what a budget meter misses. Find a specialist via our Find a Dealer hub.

Furthermore, ensure the caravan has a full service history to keep any remaining anti-water ingress warranties valid. Many manufacturers, including Swift and Bailey, require annual inspections at an approved centre within a strict window (usually 6 weeks either side of the purchase anniversary) to maintain these 6-to-10-year guarantees. Before buying, use our Caravan Towing Calculator to ensure your car can safely pull your chosen model.

Checklist: Pre-Purchase Damp Inspection

Area	What to look for
Awning Rails	Gaps in sealant or loose screws along the entire length.
Grab Handles	Firmness when pulled; internal wallboard softness behind handles.
Floor Edges	Discolouration or 'softness' when probed from underneath the chassis.
Window Rubbers	Cracking, shrinking, or green algae build-up.

FAQs: Caravan Damp

Can I fix caravan damp myself?
Minor resealing of rails is possible for a competent DIYer, but structural timber rot usually requires professional intervention to ensure the van remains safe and towable. Modern composite vans may require specific bonding agents that aren't available at retail.

Does a 'dry' report mean the van is perfect?
Not necessarily. A report is a snapshot in time. If a van has been under a cover or in dry storage for months, active leaks may not show high readings until it has been out in the rain for several days.

What is the difference between damp and delamination?
Damp is moisture ingress into the walls or floor. Delamination is when the layers of the floor (plywood and foam) separate, causing a 'spongy' feel. While damp can cause delamination, the latter can also occur simply from heavy foot traffic over time in high-use areas like the galley.

Next Step: View our used caravan listings with confidence, and always prioritise reputable dealers who provide a comprehensive damp report as part of the sale.