How To Get Rid Of Damp In A Caravan

Damp is a sad fact of life, whatever type of property you own. But caravans are particularly prone to damp, water ingress, and mould for various reasons. For one thing, they tend to be more exposed to the elements, which can result in leakages and compromised sealants. Many caravan owners also put their caravans into storage during the colder months, only to find them plagued with damp and mould issues when they take them out again.

To find out how to combat damp in a caravan, we speak to vloggers Jamie and Stacey from The McNeills on Wheels and Jonathan Anderson from caravan dealership Caravan Source.

damp in caravan

Pictured: Jamie and Stacey

damp in caravan

Pictured: Jonathan

Jamie and Stacey have lived full-time in their caravan – a 1999 Elddis Knightsbridge – since 2018, and extensively repaired its front end following water ingress and damp issues. Jonathan also has ten years’ experience in caravan sales, servicing, and maintenance.

Let’s find out what they have to say.

 

Table of contents

1. What should you do if you find damp in your caravan?

2. How can you remove damp, mould, and mildew?

3. How can you prevent damp in your caravan

4. How should you dry out your caravan? 

5. What are the tell-tale signs that a caravan has damp? 

6. Where are caravan owners most likely to find damp? 

7. How important is it to invest in a damp meter?

8. Is there anything we've missed?

 

1. What should you do if you find damp in your caravan?

The McNeills On Wheels:

“Damp” in caravans is a broadly used term to describe an increase in moisture within the caravan. This increase is usually caused by one of two processes: condensation or water ingress. Before you take any remedial action, you need to determine whether the damp you’ve found has been caused by condensation or water ingress.

Condensation

Condensation occurs naturally due to changes in atmospheric moisture content and temperature. When temperatures fall, the moisture in the air condenses on surfaces that are colder than the surrounding air. Surfaces may feel cold and wet to the touch, and over time you may observe black mould spores growing on surfaces. Fabric and material items may also show signs of black mould, which presents itself as a speckled pattern of black dots.

Usually, condensation will not cause a significant weakening of the caravan structure in the short-term. The main issue is the potential impact on your respiratory health, as the spores released by the black mould during the fungi’s reproduction cycle can irritate the lungs of vulnerable individuals when inhaled.

Water ingress

In the event of discovering a water ingress issue, the first step you should take is to try and get the caravan under cover to limit further water ingress. This can be achieved by either placing your caravan under a breathable, waterproof cover or in undercover storage. You then need to assess how and where the water ingress is occurring.

Caravan Source:

If you find damp in your caravan, you should do two things:

  • Find out how bad it is. Using a damp meter or hiring a professional will give you a clearer sense of how much damp is in your caravan.
  • Look outside and figure out where water is getting in. This is usually easy as water always travels down, not up.

The cause of water ingress is typically a hole, crack, or damaged/compromised sealant somewhere on the caravan. This subsequently soaks into the wooden frame and through the wallboard. 

Mould and mildew are usually caused by condensation from drying out awnings or carpets, or from the breathing and perspiring of the caravan occupants. It could be caused by water ingress, but not always.

 

2. What steps should you take to remove damp, mould, and mildew? And how much does it typically cost?

The McNeills On Wheels:

If you discover black mould growing on your caravan’s surfaces, then wiping hard surfaces with warm water and bleach will kill the black mould. However, you may need to repeat this process and give your caravan a regular airing to fully prevent its return.

Black mould spots on fabrics can be pre-treated with diluted white vinegar, before being washed with two to three cups of white vinegar alongside your normal detergent on a hot wash. Before doing this, though, you should check any care labels on said fabrics.

Damp caused by water ingress is far more difficult to remediate. When rainwater penetrates the caravan’s outer shell, it permeates its way through the timber framework, which absorbs the water like a sponge. Frustratingly, by the time you detect water ingress damp with your hands or eyes, the damage has already been done and will be extensive. This is due – partly – to many caravan wallboard coverings having a ‘plasticky’ outer layer.

This outer surface, which is excellent at repelling condensation and is wipeable, also possesses the same ability on its inside, meaning it’s equally good at holding back any water trapped behind the wall board. This means water ingress isn’t often noticed until the damp  and damage  is significant.

Caravan Source:

Several factors will impact how much a damp removal solution costs. These factors include the size and accessibility of the area and how bad the damage is. A small area might cost £500, while a substantial area might cost £1,000. A washroom could roughly cost £2,000.

3. What should you do to prevent damp in your caravan?

The McNeills On Wheels:

A low-wattage, tubular heater will help to reduce condensation by encouraging thermal air circulation. It will also maintain a warmer temperature inside the caravan so that condensation cannot form. This contrasts with a dehumidifier, which will actively remove moisture from the air.

Individuals I have spoken to who have used a dehumidifier in their caravan have reported different outcomes – some positive, some negative. Be aware that dehumidifiers do not work well in cold air, so may require supplementary heating to maintain their effectiveness.

For those of you who don’t have access to electricity at your caravan storage, there are other options. Disposable crystal or gel dehumidifier boxes trap water through absorption. A similar, but cheaper, alternative is baking trays of table salt left in different areas of the caravan. The benefit of the table salt is that when you’re airing your caravan, you can put the salt into the oven at a medium temperature to dry it out, so you can reuse it.

You could also regularly visit your caravan when it’s in storage and run the gas heating for 30 minutes or so until the caravan’s interior feels warm. 

Whenever you leave your caravan in storage, you need to open all cupboard doors, lift seat cushions, and store them away from the caravan walls to enable maximum airflow. If possible, store your seat cushions at home. While doing this, make sure all food is removed from your caravan, so it doesn’t attract pests such as mice or rats.

Caravan Source:

Damp and water ingress are inevitable at some point, just as rust is inevitable with a car. Therefore, it’s crucial to get your caravan serviced. A service checks the safety of every aspect of the caravan and includes a damp test which is guaranteed to find damp if it’s in there.

It’s possible to stay on top of water ingress by checking the condition of all the sealant and joints on the caravan roof, awning rails, mouldings, and above windows. Checking these areas will help you to ensure there are no holes or gaps.

 

4. How should you dry out your caravan?

The McNeills On Wheels:

The best way to counter condensation is to frequently ventilate your caravan on dry, breezy days. Regularly airing your caravan will dry any condensation within it, which limits the potential for black mould to develop.

Also, as previously mentioned, if you have access to electricity where you store your caravan, then you may also wish to consider using a tubular heater and/or a dehumidifier to help reduce condensation within it.

Caravan Source:

Leaving the heating on a low setting will dry out your caravan over time.

When using a dehumidifier, be careful not to overdo it. Wood has a normal moisture content of about 12-15%, so it could split if it’s dried out too much. If the wallboard is soaked and spongy, then a repair is necessary to retain the caravan’s safety and integrity.

 

5. What are the tell-tale signs that a caravan has damp?

The McNeills On Wheels:

If, when feeling the caravan walls, you feel a soft, spongy section, or can see bubbling or blistering of the plastic wallboard covering, then this could be a sign of water ingress. As such, you should check it with a damp meter right away.

It’s worth pointing out that if you suspect damp is a problem and your caravan is still within warranty, you should alert your dealer. Don’t attempt any form of inspection or try to carry out repairs yourself, as this may invalidate your warranty. If, however, your caravan is out of warranty, we recommend using a damp meter or enlisting the services of a caravan engineer who specialises in surveying caravans for damp.

Caravan Source:

Some caravanners claim to have gone 30 years only using their nose to tell them if a caravan is damp. While that’s a nice notion, it sadly isn’t much use as what they’re really smelling is rot, which happens when damp is left untreated. Ideally, the damp would’ve been caught long before they got to this stage.

You can’t beat the peace of mind that comes with an annual inspection for damp by a servicing engineer, but softness of the wallboard or underneath the floor are tell-tale signs. Again, though, by the time this is noticeable, the damage may already have been done.

Some wallboards discolour to a shade of blue if they come into contact with water. This process happens quite quickly, so that’s a good way to spot damp within your caravan.

If you see corrosion or small powdery holes on the outside of your caravan, this is likely to be panel rot. Panel rot is usually caused by the wood behind being so damp that it’s started to rot through the aluminium over time.

Lastly, if you notice any gaps in the caravan’s sealant this is often a sign there’s damp inside – or, if not, there will be soon.

 

6. Where are caravan owners most likely to find damp?

The McNeills On Wheels:

In the case of water ingress damp, prevention is far better than cure. Regular testing of all areas where water could enter a caravan will provide you with an early warning of potential problems.

Your list of areas to focus on should at least include:

  • Behind the toilet
  • In all upper cupboards where the wall meets the ceiling
  • In all lower storage areas where the wall meets the floor
  • Around the windows
  • All internal seam joints
  • Any areas in which pipework or other items enter or exit the caravan 

Old caravan mastic is a common failure point. Mastic is a flexible gum substance that is placed between the outer rails and other fixings on the outside of the caravan and caravan body.

The mastic, which is soft and flexible when young, becomes dry and brittle with age. Vibration, knocks, and body movement during towing or windy weather can cause cracks to occur in this mastic. These cracks then allow rainwater access to the caravan interior via screw holes, window seals, and body seams. In winter, the deterioration of poor mastic is further accelerated by freeze-thaw action, which pushes the caravan rail further from the caravan body.

The expected lifetime of mastic varies depending on how well it was applied originally, how frequently the caravan has been towed, and how and where it has been stored when not in use. However, I’d advise replacing mastic every five years if you tour full-time in your caravan, or 10 years if not.

Unfortunately, whilst replacing mastic is a straightforward task in theory, it’s incredibly time-consuming. Despite the mastic’s age, it should retain a strong bond to the caravan body when removing rails and fixtures. As such, it will require great care to prevent damage to the body of the caravan or the item being removed.

White spirit helps to dissolve and weaken the bond of the mastic enormously. However, be sure to thoroughly clean all areas with methylated spirits to remove all traces of white spirit and enable good adhesion of the new mastic.

Whether mastic is indeed the culprit or not, it’s essential to maintain accurate records of the moisture content percentage of the areas tested. It’s also helpful to record the outside temperature and weather conditions on the day tested, as these can impact the results obtained. Ideally, you’re looking for a moisture reading of less than 20%. Readings higher than this could indicate water ingress, whereas readings over 40% signify serious water ingress.

Caravan Source:

You’re most likely to find damp or the cause of damp anywhere it’s possible for sealant to fail, as this can allow water to creep in and move down. This includes areas such as:

  • Under any seams and joints on the outside of the caravan
  • Below awning rails
  • Below mouldings on both sides
  • Around roof-lights
  • Around vents
  • Under windows
  • Around door catches
  • Around cupboard and door handles 

 

7. How important is it to invest in a damp meter?

The McNeills On Wheels:

Basic damp meters are inexpensive, typically around the £20 mark. Whilst they won’t have the accuracy of the more expensive units, they’ll provide you with comparable data over time, which you can use to assess whether to take action or not.

Caravan Source:

It’s worth bearing in mind that some damp meters can leave nasty visible holes all over the caravan. These holes will decrease the value of your caravan, so be careful which damp meter you buy. The damp meters the trade use are largely non-penetrative testers that leave no holes at all, so, again, I’d recommend getting a professional in.

There are so many different damp meters on the market as well, so do your research first.

 

8. Is there anything we’ve missed that you think our readers might find useful to know when handling damp?

The McNeills On Wheels:

If you’re willing to repair water ingress, you may decide to just live with the damp area in your caravan.

Over time, it’ll dry out, but be aware that the caravan structure may be compromised depending on the extent of the damage caused. The structure may make it unsafe to tow or possibly even dangerous to occupy in strong winds in case of collapse.

If you do decide to go ahead and replace any rotten timbers, the cost can be low if you decide to repair your caravan yourself. We recommend using timber and plywood from your local builders’ merchants.

However, if you need to contract a caravan engineer to do the repair work for you, labour costs can quickly mount up. Sometimes, this means even small repairs aren’t economically viable, especially for older caravans. That’s why many are sent for scrap with damp issues that are easily fixable.

On the brighter side, if you do decide to repair an old caravan, you’ll find enormous pleasure and joy in the process. That’s what we did when water ingress led to damp in our caravan which you can view below.

Caravan Source:

Damp is inevitable for most caravans at some point, but if it’s caught early (either through regular inspections or by using a reliable damp meter), you can usually find the cause and put it right.

This could mean re-sealing the caravan, having a workshop over-seal the existing seals, or removing and replacing a rail, moulding, or rooflight. We’ve actually made a video where we look into what to look out for when buying a used caravan.

Also, as a side note – spongy floors are sometimes attributed to damp, but are often caused by delamination, so that’s worth bearing in mind.

 

Specialist touring caravan insurance from Ripe Caravans

Ensuring you regularly maintain your caravan and resolve damp issues is just one essential step in looking after your caravan – another is specialist touring caravan insurance.

At Ripe Caravans, we cover your touring caravan against loss, theft, and damage, and offer a whole host of extras such as awning cover, hotel and caravan hire, and much more. Click the link above to find out more, and get an online quote in minutes.

 

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