What causes mould in caravans?

In this article, we will answer the following question: What causes mould in caravans? We will discuss the reasons behind unwanted mould spots in a caravan, how to prevent and deal with them.

What causes mould in caravans?

Mould in caravans is most of the time caused by high levels of humidity.  With the arrival of autumn, temperatures drop, the rains begin and humidity levels increase. This situation can aggravate the structural humidity problems suffered by caravans.

Condensation issues also increase. These humidities appear inside the houses due to the water vapour in the environment that is generated with daily actions, such as cooking or showering, in addition to improper ventilation. 

  • fungi and mould in corners and walls; 
  • fogged glass in windows and mirrors; 
  • furniture and other deteriorated objects and even risk in electrical installations.

These are the most visible effects of humidity produced by condensation.

But the most alarming consequences of living with a humidity problem are those related to health. Diseases such as asthma or sinusitis; respiratory and dermatological allergies; headaches or rheumatic problems appear and worsen if you live in a humid environment, with children and the elderly being the most vulnerable population.

What percentage of damp is acceptable in a caravan?

A maximum of 15% of damp is more than acceptable in a caravan. If the humidity level regularly exceeds 70%, it can cause rust, mould, musty odour and rot. To remedy this, dehumidification must be carried regularly. 

If there is a high percentage of damp in a caravan, the high humidity levels can be due to internal or external factors.

Internal factors that can create dampness in a caravan:

  •   You have not emptied the water tanks and there has been a leak;
  •   You have left a blanket inside that has absorbed the humidity from the environment;
  •   You unplugged the fridge but it was closed and it was damp and cold for a long period.

External factors that can create dampness in a caravan:

  • A window has been damaged by the sun, water and cold, it has given way and water has entered;
  • Puddles have been created in the ceiling and have ended up getting into the internal materials of the ceiling, by the fixing screws of the accessories or by the skylight.

Quick tips to avoid high humidity in a caravan

  1. A fundamental tip to avoid high humidity in a caravan is to carry out an inspection every year to avoid further damage. It is convenient to remember that when we observe humidity in our caravan, the filtration has occurred for a long time and it has been able to damage the structure without realizing what the cost of the repair can multiply. 

The structures of motorhomes are generally made of wood, which is very absorbent to water and ends up rotting.

  1. Visually check the condition of the exterior sealants. If we detect that they are cracked, broken or hardened, there is no doubt – we must replace them.
  1. Park the caravan (if possible) with a certain inclination, so that there is no stagnation of water on the roof. Many motorhomes have flat roofs and become pools of water. This causes the water level to rise on the roof and seep through skylights or profiles. 
  1. Although it may not seem like it, interior condensation is also a problem that can generate breakdowns. As in any building, airing is convenient. And if possible use dehumidifiers from time to time.
  1. Using awnings if we park a caravan outside is essential. But you have to use awnings that allow room to breathe or semi-awnings that only cover the roof. Because if the awnings are too tight we will cause external condensation.

How to remove mould from a caravan?

Mould in a caravan can be the result of roof leaks that went unnoticed. Mildew – a type of mould that thrives best in heat and humidity – is easy to remove, but stains left can be stubborn.

If you are concerned about the musty smell and fungus on the walls, the first thing to do is remove the black or green stains from the wall, cleaning the area well. Try some of these effective techniques to do it:

  • Lavandin: it is one of the best disinfectants.
  • Sodium bicarbonate: makes the smell of humidity and confinement disappear.
  • White vinegar: used to eliminate all types of mould.
  • Hydrogen peroxide: it is very effective and also has disinfectant properties.

Mould and fungi are formed mainly by three factors: the humidity produced by those who inhabit the house, the poor ventilation of the environments and the water leaks (in general, from the pipes that go inside the walls).

The first factor refers to all those actions of our day to day in which we produce humidity inside our houses: bathing, cooking or simply breathing. When combined with poor ventilation of the environments, the second key factor for the formation of mould, the place becomes more prosperous for this organism to emerge.

The third factor that helps mould growth is water leaks. These produce even more humidity in the environment, very conducive to the formation of fungi and mould.

Some final (and useful) tips that we can give you to prevent fungus and mould inside your caravan is that you always keep it illuminated (with sunlight) and ventilated.

Also, whenever cooking or after showering in your caravan, make sure you open a window or two, and that you always properly clean and maintain your caravan. 

How to prevent mould in a caravan?

To prevent mould in a caravan, use an anti-humidity dry-ball in the caravan. One of the best solutions and one of the easiest to put into practice is to place this humidity sensor

The dry-ball is a plastic device that is designed to absorb it thanks to internal crystals, made up mostly of calcium chloride salts that are drying. This accessory does not produce gases, odours, or smoke and much less steam.

Also, it is essential to ventilate the caravan every week, preferably once or twice in the morning. In addition to checking the status of the caravan or motorhome, by ventilating the area, we will ensure that there is no concentration of humidity. You must emphasise the bathrooms and bedrooms as they are smaller rooms and will have more condensation.


A well-maintained caravan or motorhome can be a travel companion for a long time and as you can see, preventing a high level of humidity in a caravan and dealing with mould is not complicated at all. We hope these tips have helped you.

Please let us know if you have any comments or questions about the content. 

FAQ on What causes mould in caravans?

How do I keep my caravan damp-free?

To keep your caravan damp-free you must keep it ventilated at all times, shower outside when possible, cook with the windows/door open, don’t dry your laundry inside the caravan and invest in a good humidifier. 

How to remove mould on fabric?

To remove mould on fabric, it is recommended to use bleach. What you should do is fill a bucket and for each litre of water add half a cup of bleach. Let the garment soak for a couple of hours and, to finish the process, wash it as you always do.

How to remove mould from awning?

To clean a mouldy awning follow these recommendations:

  1. Thoroughly moisten the canvas or plastic awning with hot water.
  2. If the stains are not recent, use a grease remover to make them easier to remove.
  3. Rub gently in the areas to be treated so as not to damage the awning fabric.

What percentage of damp is acceptable in a caravan?

A maximum of 15% of damp is more than acceptable in a caravan. If the humidity level regularly exceeds 70%, it can cause rust, mould, musty odour and rot. To remedy this, dehumidification must be carried regularly. 


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