Damp is the problem every motorhome and caravan owner dreads, and for good reason. It rarely announces itself. Water finds its way in through a tired seal or a roof joint, soaks quietly into the timber frame and wallboard, and by the time you can see or smell it, the damage behind the panels has often been growing for months. The good news is that most damp is predictable, and caught early it is usually a far smaller and cheaper job. This guide covers the warning signs to look for, where damp usually gets in, how to tell it apart from ordinary condensation, and what to do if you think your van has a problem.
Is it damp, or just condensation?
Not all moisture means a leak. It’s worth knowing the difference before you worry:
- Condensation comes from inside the van: breathing, cooking, showering and drying clothes. It collects on cold surfaces like windows and metal frames, and usually clears once the van is heated and aired.
- Water ingress comes from outside, through seals, joints and fixings. It tends to show up in one particular area, often a corner, and stays damp even when the van is warm and well ventilated.
Quick check: if the moisture is mostly on windows and disappears with heat and airflow, it’s probably condensation. If one corner or cupboard stays damp, especially after rain or a spell in storage, treat it as a possible leak.
The 5 warning signs of damp
1. A musty or stale smell
Often the very first sign, especially when you open the van after rain or storage. It usually means moisture has been sitting in the wall or floor long enough for mould to start. Close the van up for an hour, then open the door and smell around the corners, under the beds and seat bases, in the washroom, and around rooflights and the over-cab area.
2. Soft or “spongy” wall panels and floors
Press gently on the wallboard in lower corners, around windows and under lockers. Healthy panels feel firm. If a panel gives, flexes or feels spongy, the timber behind it may already be affected. The same goes for floors that feel soft near doors or in the washroom.
3. Staining, tide marks or dark patches
Discolouration on walls or ceilings, brown tide marks, or grey and black spotting are all signs that water has travelled through the structure. Look closely around window corners, rooflights, the rear panel and along the line of external trims.
4. Peeling, bubbling or lifting surfaces
Wallpaper that’s peeling, a wall surface that’s bubbled, or vinyl flooring that’s started to lift can all be caused by moisture underneath. These signs often show up well after the leak started.
5. Condensation that won’t clear
Some condensation is normal. But if you’re getting heavy condensation even with the heating on and vents open, or it keeps coming back in the same spot, it’s worth having the van checked properly.
Where damp usually gets in
Most damp starts at one of a handful of weak points. Knowing where they are makes it much easier to keep on top of them:
- Window and door seals. Rubber seals shrink, harden and crack with age and sunlight.
- Rooflights and roof joints. The roof takes the most weather, and the movement of driving puts stress on every joint.
- Ageing sealant. The flexible sealant behind trims and joints hardens over the years and starts to crack, leaving gaps you can’t see.
- Awning rails and side trims. Long runs of fixings along the side of the van are a common entry point.
- Rear panel corners and lower skirts. These take spray from the road and knocks from everyday use.
- Hatches and lockers. Service hatch and locker door seals wear just like window seals.
- Anything fitted later. Every screw or cable entry for a bike rack, solar panel, satellite dish, ladder or aerial is a potential leak point if it isn’t sealed properly.
- Small knocks left unrepaired. A minor scrape or crack in the bodywork can let water into the structure behind it.
How to help prevent damp
- Have a professional damp check at least once a year. It’s part of a proper habitation check.
- Walk round the van every few months and look at seals, trims, rooflights and anything you’ve had fitted.
- Keep the van ventilated, including during storage. Leave vents clear and use a dehumidifier if you can.
- Heat and air the van after trips, and avoid drying wet clothes and towels inside with the windows shut.
- Get small knocks and cracked seals repaired promptly rather than leaving them until the next service.
- Make sure any accessories are fitted by someone who seals every fixing properly.
What to do if you think you have damp
- Don’t ignore it. Damp doesn’t dry out on its own once it’s in the structure, and it spreads.
- Note what you’ve found. Take photos of any marks, soft spots or problem areas, and note when you first noticed them.
- Get a proper damp test. A trained technician takes readings all round the van with a moisture meter, and can tell whether it’s condensation or a genuine leak, and where it’s coming from.
- Fix the cause, not just the symptom. Wiping away mould or covering a stain won’t solve anything if water is still getting in.
Act straight away if a panel or floor feels soft, damp keeps coming back in the same place, or you can see water getting in. That usually means the timber behind is already affected, and the sooner it’s repaired the smaller the job.
Frequently asked questions
Can I test for damp myself?
Your own nose, eyes and hands will catch many early signs, and cheap moisture meters are available. But readings need to be taken in the right places and read correctly, and a professional check will spot problems long before they’re visible.
Is damp only a problem in older vans?
No. Damp can affect vans of any age, often from a single poorly sealed fitting. Newer vans are just as worth checking, especially as many manufacturers’ water-ingress warranties depend on regular checks.
Can damp be repaired?
Yes. Caught early, it can often be sorted by resealing the source and letting the area dry. Where the timber has been damaged, the affected section is repaired. Either way, the earlier it’s found, the less work it needs.
Worried about damp? We can help
Our technicians at our AWS-approved workshop in Wallsend carry out damp checks and
damp repairs on motorhomes and caravans of all makes. Find out more about
why a yearly damp check saves you money, or get in touch:
