Caravan advice: how to prevent and deal with damp
Words: Jim Blackstock
There’s little more guaranteed to strike fear into the heart of a caravan owner than the word ‘damp’.
In the best case, it may be a little condensation after a chilly night; in the worst, it can be the death knell for the caravan, thanks to rotten framework or floors. But if you keep on top of it, and spot it early, there’s no reason damp in your caravan should necessarily mean game over.
Maintaining ventilation in your caravan
Damp is caused when moisture finds its way inside the caravan. How significant damage from damp can be, and how easy it is to deal with, depends on what the caravan is doing at the time.
If you’re actually away in the caravan, then the easiest way to prevent damp forming is to ensure that moisture doesn’t build up inside – and that means maintaining ventilation.
Moisture can be generated by showering or washing, washing up, cooking or simply a family of four sleeping inside.
There is no way to prevent the moisture being generated by any of these situations and, in fact, most people will be familiar with a slight damp feeling on surfaces or under bedding in the morning, especially after a chilly night.
However, the key to prevent this moisture becoming a problem by developing into damp is by opening doors and windows and allowing as much air around the caravan as soon as possible afterwards.
You shouldn’t need telling but when cooking, for example, opening a window or the roof vent will allow warm – and moist – air to escape before it collects. Similarly, if you use the shower, then open a window when you’re done – this will allow the worst of the steam out and prevent it collecting.
Also try to avoid drying wet clothes inside the caravan. It may not be possible, especially if you have decided not to put an awning up, but if you can, leave them in the awning or see if the site you’re staying at has a launderette and use the tumble dryer there.
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Preventing damp when the caravan is not in use
For short periods of time when the caravan is not being used, again, ventilation is key. During the spring, summer and early autumn months, you can probably leave one or two of the windows on their ‘night latch’ setting between trips away, which will prevent anyone or anything getting in but let some air flow around the caravan.
As long as it isn’t particularly cold, this will help to prevent moisture collecting inside the caravan.
Storing the caravan for longer periods is a different matter. If you’re laying the caravan up for winter, then you shouldn’t leave windows or vents open, as they will allow damp air in, rather than ventilation to disperse it.
In this case, you are better off closing all the windows and vents and opening as many cupboards and doors as you can to promote what ventilation is available. Remove all bedding, so this doesn’t absorb moisture, and to reassure yourself, you could invest in a moisture trap or a dehumidifier.
A moisture trap will be based on moisture-absorbing crystals that take the moisture from the air and once the crystals have absorbed their capacity, you will need to replace the trap.
Alternatively, a dehumidifier will remove moisture from the atmosphere constantly and some can be set to maintain a healthy humidity within the caravan, automatically switching on, sampling the humidity and removing moisture if necessary.
To ease the process, look for one with a permanent drain you can run out through one of the sink outlets or a floor vent to prevent having to constantly empty the catch tank.
Prevention of damp by managing water ingress in your caravan
Of course, one of the easiest ways to prevent damp is to prevent water ingress at all. While it may be impossible to completely eradicate any route into the caravan for airborne moisture, certainly large-scale ingress should be avoidable; close windows and doors properly and make sure roof vents are closed solidly.
If you have any electrical components on the outside – TV aerials, solar power systems or radio aerials, for example – then ensure that seals are in good condition and consider a refresh with sealant if they are looking a bit tired.
Similarly, look closely at the exterior of the caravan; there may be an issue that allows water into the void between the inner and, outer skins that you are unaware of and this is what causes the big problems.
So, check seams, particularly in the roof, for signs of old, cracking or decaying seals and if necessary, be ready to make them watertight. Also check around heater, cooker or fridge flues to make sure they, too, are sealed against the elements, as it doesn’t take much wind to help water find its way in through the smallest crack.
Similarly, heater flues or bathroom vents in the roof should also be checked, both inside and out, to make sure that they aren’t allowing water in. If they are, then again a careful application of sealent (once completely dry) will help to keep the moisture out.
Finding damp in your caravan
If moisture has found its way into your caravan, then eventually you will come across it. It might just be condensation from cooking or sleeping and that’s easy to get rid of, as we’ve already covered.
However, it may well be worth investing in a damp meter (particularly if you’re looking at buying a secondhand caravan) to search out any moisture in the caravan’s interior.
Damp meters aren’t expensive and can save you a fortune if they help you spot – and avoid - a damp caravan. While your pre-season annual service should include a series of damp checks, it won’t get into every nook and cranny so it’s worth investing in one to keep a good check on your caravan.
The service should check around the door and vents but you can get under the seats, into the far corners, inside all the high – and low – level cupboards and underneath the cooker or inside the wardrobe.
Generally speaking, a damp meter should give you a percentage reading and 0-15% is usually regarded as no cause for concern.
Areas with a reading of 15-20% should be kept an eye on and checked periodically to see if they change, while a reading of 20-24% would indicate moisture is entering and should be investigated more. 25-30% would indicate definite water presence and repair work required while 31% and above is a bit of a mess and may mean significant structural damage is likely.
If you don’t have access to a damp meter, then running your hands over the surfaces will often tell you whether there is surface moisture present or the surface itself is damp.
Apply a little pressure as you go around to make sure that the walls, for example, don’t feel soft or spongy and do the same on the floor, making sure it all feels solid.
Look for tell-tale areas of bubbling on the interior finishes, staining in corners of the ceiling or signs of mould or mildew forming and in very bad cases, you will be able to smell damp long before you see it. In this case, things are likely to be in a state…
Dealing with damp in your caravan
If you do come across damp, then don’t panic and work through things logically. The first thing to do is work out where and how water is entering and plug the leak.
If the caravan has been stored, for example over winter, then clearly the water has entered from outside, so give the exterior a good inspection to work out where it is coming from. When you discover the source, either repair it yourself or if you’re not confident, get a professional to do it.
Once you’ve stopped water getting in, you’ll need to dry the interior thoroughly. Again, we’re back to ventilation and if necessary, a dehumidifier. We generally avoid heaters, as they can convert damp into airborne moisture that could hinder the process. A dehumidifier will simply remove any moisture from the surrounding environment and that’s what you want.
When the moisture has been removed, you may need to tackle mould or mildew. But be very careful – mould spores can be given off when it dries and get in the lungs and can affect the breathing, especially for those with problems like asthma. So wear a mask whenever you’re working on mould.
You can use a proprietary mould product but a 50/50 mixture of vinegar and water will work as well, to kill the mould. Spray the area then let it dry. Spray again and use the same product to wipe the area clean. The vinegar will kill the mould and prevent it from returning once you have cleaned it away. In our experience, it doesn’t actually leave a smell at all.
If the caravan smells musty, then a good airing, along with any seat cushions, for example, will help freshen it up and a good scrub of the carpets (if fitted) or the flooring will also help.
If you are unlucky enough to find areas of spongy walls or floors or interior finishes that are damaged, then it might be time to call in the professionals, as tackling damaged walls or floors or even framework is a lengthy and complicated process and is not for the faint-hearted.
But as with so many things, prevention is far better than cure, so keep the water out, open the windows when you can and avoid the damp plague.
You can read more caravan advice from Jim Blackstock here, as he details how to get your caravan set for the summer season