How To Prevent Damp in Caravans and Motorhomes

Nobody wants to open their caravan or motorhome after winter and discover a musty smell or black mould inside. Damp and condensation are common problems, especially during cold, wet months. They make your vehicle uncomfortable and can even affect your health. The good news is that preventing damp is far easier than fixing it. In this guide we cover everything you need to keep your motorhome, caravan or campervan dry and cosy, including what to avoid, practical tips and recommended checks. Follow these steps and you can avoid that dreaded damp nightmare on your next trip.

Understanding Damp vs Water Ingress

It helps to distinguish two different issues: condensation damp (from indoor moisture) and water ingress (from outside leaks). 

Condensation damp

Condensation happens when warm, moist air (from cooking, showering or breathing) meets cold surfaces such as windows or walls, causing tiny water droplets to form. This can lead to wet fabrics, mould on ceilings, or a general clamminess inside. 

Water ingress

Meanwhile, water ingress means that water is getting in through a gap - for example through a cracked rooflight seal or a loose door fitting. A leak like that can soak into the structure and cause serious long-term damage.

In short, condensation and mould from moisture inside are usually fixed by better ventilation and humidity control; leaks from outside require finding and sealing the gap. In either case, the key is to detect and tackle the issue early.

Signs of Damp To Watch For

Here are common warning signs that your caravan, motorhome or campervan may be damp or suffering from water ingress:

• A musty or mouldy smell when you first open the doors. Damp odour is often the first clue. 
• Dark patches or black mould spots on walls, ceilings or around windows and doors. 
• Discoloured seals or corners often mean condensation has been feeding mould growth. 
• Soft, spongy-feeling panels when touched. Moisture may have penetrated the laminate. Floors or upholstery that spring back slowly after pressing may indicate damp saturation.
• Visible condensation on glass or windows, especially in the morning. Rust or corrosion on metal fittings or appliances (like hinges or screws) may also show persistent moisture.

If you notice any of the above, act quickly. A small damp patch is much easier to dry out than rotten floor panels or warped walls. Many owners say that investing in a moisture meter can pay off, it often spots hidden damp before it becomes obvious.

Why Damp Happens in Caravans and Motorhomes (Common Causes)

Damp in a caravan, motorhome or campervan usually arises from one or more of the following issues:

• Everyday moisture: Simple things like cooking, showering, breathing, or wet gear (like towels or pets) release water vapour into the air. When warm, humid air meets cold surfaces, condensation settles on walls, ceilings or windows. 
• Poor ventilation or airflow: If roof vents, windows or air inlets get blocked, or if the vehicle is sealed up during storage, humid air cannot escape and condensation builds up fast.
• Leaks and defective seals: Cracks around windows, doors, rooflights or external fittings (e.g. vents, pipe inlets, awning rails) can allow rain or moisture to seep into the structure. Even a small gap can lead to moisture creeping under panels. 
• Long storage periods without airing: If you store your caravan, motorhome or campervan for months without ventilation and with items like bedding inside, humidity levels can rise and cause damp over time. 
• Damp items inside: Storing wet boots, towels, clothes or sports gear inside will release moisture as they dry. This increases indoor humidity and encourages mould growth.

Often damp is the result of a combination of these factors. For example, cooking in a sealed kitchen with no vent, followed by closing cupboard doors, can trap moisture inside and lead to condensation. The key is to break the cycle by controlling each source of humidity.

Ventilation and Airflow in Your Caravan or Motorhome

Good ventilation and airflow are the most effective ways to prevent condensation and damp.

Make it a habit to keep air moving around your caravan, motorhome or campervan:

• Use extractor fans and roof vents. Whenever you cook or shower, make sure vents are open or crack a window to let steam escape. Even leaving a small opening for 10 minutes during moisture-heavy tasks can help a lot. 
• Avoid blocking vents. Do not wedge furniture or storage items in front of air inlets, or tape over them - they are there to ventilate.
• Keep cupboard and wardrobe doors slightly open when the van is not in use, especially during storage. This allows stale air to circulate and reduces the risk of mould forming inside confined spaces. 
• Maintain a low, steady background heat and occasional ventilation when stored over cold months. A mild heater can keep interior walls slightly warmer than outdoor surfaces, lowering the chance of moisture condensing.

In short: a little airflow goes a long way.

Manage Moisture Sources From Daily Life

It is not enough to ventilate, you also need to reduce unwanted moisture generation inside. Simple daily habits can make a big difference:

• Dry up spills immediately. Any liquid from cooking spills, rainwater on boots or pets, or wet towels should be dried thoroughly as soon as possible. Leaving damp items around will raise humidity and feed mould. 
• Dry clothes and wet items outside if possible. Towel-dry pets before bringing them inside. If you must dry clothes inside, run a dehumidifier and keep windows or vents open at the same time. 
• After showering or cooking, allow steam to escape. Use extractor fans or open windows. Close the bathroom or kitchen door (if internal partitions exist) so humidity does not spread through the living area. Wipe down wet surfaces afterwards. 
• Wipe condensation regularly. Keep a microfiber cloth or squeegee handy, and wipe any water droplets from windows, walls, or cold surfaces. This helps stop water dripping into seams, fabrics or corners where mould could grow.

By controlling both the source and escape route for moisture, you significantly lower the risk of damp.

Keep Your Caravan or Motorhome Clean and Inspect Regularly

A clean, well-maintained caravan is less likely to develop damp issues and more likely to reveal small problems early, before they escalate.

Keep on top of these checks to try and keep damp at bay:

• Clean and vacuum surfaces, carpets and upholstery regularly to remove dust and mould spores. Wipe down kitchen and bathroom surfaces with a mild detergent or anti-bacterial cleaner. 
• Inspect seals and joints around windows, doors, rooflights, vents, and any exterior fittings (such as vents, awning rails, pipe inlets or external TV/solar aerials). Old or cracked sealant, shrunk gaskets, rust on screw heads or soft spots near seams may signal water ingress - reseal as soon as possible. 
• Do not ignore small leaks or damp patches. Sometimes a tiny leak can run along a timber frame before ever appearing on the interior wall. Mould under a cupboard, for example, may start from a small gap in the roof.
• As part of regular maintenance or before long storage periods, consider a full inspection or habitation check (often offered as part of caravan or motorhome servicing). Experts may lift floorboards, test moisture levels, and reseal the roof or joints as needed.

Routine checks and quick action are vital. Catching issues early can save a lot of trouble later.

Useful Tools and Moisture-Control Aids

Alongside good habits, a few simple tools and aids can help keep moisture under control even when you’re not present:

• Moisture absorbers: (desiccant crystals or moisture-absorbing bags) You can place these in wardrobes, under beds or near sinks and lockers. They passively draw humidity from the air. 
• Small dehumidifier: A small electric dehumidifier (if you have shore power while stored) can make a big difference. These remove moisture from the air consistently and can reduce humidity levels more effectively than passive crystals. 
• Humidity gauge: A humidity gauge (hygrometer) or damp meter helps you monitor air moisture levels. If relative humidity stays above roughly 60%, you should increase ventilation or run a dehumidifier. Squeegees/microfiber cloths: Window squeegees or microfiber cloths to wipe off condensation. This small habit helps prevent water dripping into seams or pooling on floors. 
• Insulation: Insulation and thermal blinds or curtains (for colder months). Proper insulation reduces temperature differences between inside air and cold surfaces, lowering condensation risk. Closed-cell foam or thermal fabrics can help.

Combined, good airflow, regular cleaning and moisture-control aids give a strong defence against damp.

Mistakes That Can Cause Damp in Your Caravan or Motorhome

Knowing what to avoid is just as important as knowing what works. Here are common pitfalls that tend to make damp problems worse in caravans, motorhomes and campervans:

• Blocking vents: Do not block vents or seal your caravan, motorhome or campervan completely, especially with plastic tarps or non-breathable covers. That traps moisture inside, turning your vehicle into a damp box. 
• Leaving wet items around: Do not leave wet items inside. Wet boots, soggy towels, rain-soaked clothes or pets will dump moisture into the air as they dry. Always dry outside if possible. 
• Ignoring leaks and condensation: Do not ignore small leaks or condensation signs. Even small gaps or damp spots can escalate over time. Water often travels under floorboards or through wall panels before you see visible damage.
• Not using specialist cleaners: Do not rely on bleach or harsh chemicals to kill mould long-term. While bleach might remove visible mould, it does not always kill spores, and it may damage interior surfaces. Use gentle anti-mould cleaners or specialist products instead. 
• Skipping maintenance: Do not skip inspections or maintenance. Over time, seals degrade, joints loosen and materials age. Without regular checks, you may not notice hidden damp until it becomes serious. 
• Relying on passive moisture traps: Do not depend solely on these if condensation is severe or you store your vehicle long-term. They help, but are not a substitute for proper ventilation, heating, or dehumidification.

Seasonal & Storage Advice

If you winterize or store your caravan, motorhome or campervan for long periods, taking extra care is essential:

• Before storing clean thoroughly, remove all bedding, cushions, mats, towels and clothing - anything that can trap moisture. Open all cupboard and wardrobe doors to allow air circulation. Keep your vehicle stored in a dry, ventilated space if possible. 
• Use a breathable, water-resistant caravan or motorhome cover rather than a non-porous tarp. This helps block rain while letting humidity escape. 
• Use moisture absorbers or a dehumidifier inside while in storage, especially if the vehicle has shore power. This is much more effective than passive airing alone. 
• Check seals, joints and external fittings before storage. Reseal anything that looks old or cracked. As sealants age, they become a common source of leaks. 
• If you can, visit your caravan, motorhome or campervan every few weeks to air it out. Even a 30-minute visit can help reduce humidity.

These extra steps during storage greatly reduce the chance of damp problems when you return.

Why Regular Professional Caravan and Motorhome Maintenance Matters

Even with the best day-to-day habits, some problems remain hard to spot - especially small leaks or moisture behind wall panels. That is why regular professional servicing or habitation checks are so valuable. During a professional check:

• The technician will inspect the exterior, roof, windows, vents and all seals for cracks or potential leak points. 
• They may lift floorboards or open up areas that are otherwise hidden to test moisture levels. A damp meter used by a professional can detect hidden moisture before it becomes visible damage. 
• They will reseal ageing joints, replace worn gaskets or sealants, and repair any leak points found. This timely maintenance can stop water ingress before it causes costly issues.

At Chipping Sodbury Caravans & Motorhomes we offer full habitation checks as part of our caravan servicing and motorhome servicing. Our team will check gutters and drains, reseal rooflines if needed and ensure all seals and vents are intact. This thorough check-up helps catch small issues before they become big headaches.

Preventing damp in your caravan or motorhome comes down to managing moisture and airflow. With a few simple habits you can stop condensation and mould long before they start:

• Ventilating when cooking or showering
• Drying wet items promptly
• Regular airing, cleaning, and using moisture-control aids

If you combine these everyday habits with regular inspections, seal maintenance, and a good storage routine, you give your caravan, motorhome or campervan the best possible protection against damp. And if you want expert support or a full check-up, our team at Chipping Sodbury Caravans & Motorhomes are always happy to help.