section heading hidden

Why Damp Deserves Your Attention

Damp is the single most expensive problem a caravan can develop. Unlike a worn tyre or a tired battery, water ingress rarely announces itself. It seeps in quietly, works its way through timber framing and insulation, and by the time you notice a musty smell or a soft patch of wallboard, the damage behind the scenes can run into thousands of pounds. The good news is that damp is also one of the most preventable and detectable issues in caravan ownership. A little routine vigilance, a cheap moisture meter and a willingness to investigate odd smells will save you far more than they cost.

Where Water Ingress Usually Starts

Caravan manufacturers seal hundreds of joints, and any one of them can fail as sealant perishes, panels flex and screws work loose. Certain areas fail far more often than others, so start your inspection here.

• Roof seams and skylights: Rooflight surrounds, roof strap joints and aerial mounting points are prime suspects. Sealant shrinks with age and UV exposure.
• Front and rear panels: The joint between the front ABS panel and the side walls, plus the awning rail, takes the brunt of wind-driven rain.
• Corner joints: All four corners should be checked closely. Herringbone stitching or failing mastic here lets water track along the frame.
• Window surrounds: Rubber seals harden, and the screw line above a window is a classic entry point.
• Floor edges and wheel arches: Spray from wet roads can find its way through sealant around wheel boxes and underfloor joints.
• Bathroom and kitchen: Internal leaks from showers, sinks and pipework are just as damaging as external ingress.

If you only have time for a quick check, spend it on the front and rear corners and around the rooflights. That is where the majority of insurance claims begin.

Reading the Early Warning Signs

Water usually leaves clues long before it shows as a stain. Train yourself to notice the small things each time you use the caravan.

• A persistent musty or earthy smell when you open the door after storage.
• Condensation that gathers on one wall or window more than others, especially after dry weather.
• Wallpaper or wallboard bubbling, rippling or lifting at the edges.
• Screws that have rusted or gone black, particularly near window frames.
• Soft or spongy flooring underfoot, or timber that gives slightly when pressed.
• Swollen door frames that make doors stick in damp weather.

Remember that a caravan with a small leak can look immaculate inside. Stains often appear on the reverse of a panel, not the side you see. This is why meter readings matter more than appearance alone.

Using a Moisture Meter Correctly

A damp meter is inexpensive and one of the most useful tools a caravanner can own. Most caravan owners use a pin-type meter, which measures electrical resistance between two probes. Wet timber conducts more readily, so the reading rises. The trick is to use it consistently and to interpret numbers sensibly.

• Take readings in the same spots each time so you can compare results month on month. Record them in a notebook or on your phone.
• Push the pins into the timber rather than just touching the surface. Wallboard and vinyl coverings will give misleadingly low readings.
• Check inside lockers and under seating where you can access the framing directly.
• Compare like with like. A reading of around 15% in timber is generally considered acceptable in many caravans, but anything above roughly 20% to 25% warrants closer investigation. Always treat unusual jumps between readings as more significant than the absolute figure.
• Test after heavy rain, ideally within a day or two, when any leak is most likely to show.
• Use a non-invasive meter for delicate surfaces and a pin meter for exposed timber framing.

Bear in mind that cold weather, condensation and even fresh timber can influence readings. A single high number is not proof of a leak, but a consistent pattern across several checks almost certainly is.

Dealing With What You Find

If your checks reveal damp, resist the temptation to simply paint over it or run a dehumidifier and hope for the best. Damp is a symptom, not the cause. The first job is to find where the water is entering. Dry the area thoroughly, then watch it closely over a few weeks to see whether the reading climbs again.

Minor issues you might reasonably tackle yourself include re-sealing a small area of failed mastic around a locker door, replacing a perished window rubber, or cleaning and re-bedding a roof vent surround with the correct caravan sealant. Use non-setting butyl or the sealant recommended for your van, never ordinary silicone, which can trap water and make future repairs harder.

Larger problems, such as water tracking along a frame, delaminated wallboard or damp within the floor structure, need proper diagnosis and often partial dismantling. This is where a qualified caravan engineer earns their fee. They have calibrated equipment, know the construction of your model and can trace the true source rather than the visible symptom. They will also document their findings, which matters if you later sell the van or make an insurance claim.

Building a Simple Damp Routine

Ownership of a caravan is far more enjoyable when damp never becomes a crisis. A short routine, repeated a few times a year, is all it takes. Check after every significant downpour, and always before you put the van into storage and again when you bring it out. Store it level, keep ventilation open where possible, and avoid sealing it up completely, as trapped moisture causes condensation. Keep gutters and roof drains clear of leaves so water does not pool where it should run away.

Finally, book a professional damp inspection every year, ideally just before winter. A specialist will check the areas you cannot reach, spot failing sealant before it lets water through, and give you a written record of the van's condition. Combined with your own meter readings, that annual check turns a hidden risk into a manageable part of caravan life, leaving you free to enjoy the road ahead.