Mould in the crawl space - Causes and remedies

Mould in the crawl space is caused by the moisture content being too high and allowing microbial fouling. If the moisture content rises above 75 % relative humidity (Rh), the conditions for mould growth are optimal.

The mould that grows in crawl spaces is often known as white mould (Penicillium chrysogenumIt is therefore important to inspect your crawl space for mould growth at least once a year. If the mould is detected in time, it is relatively easy to fix the problem and prevent new growth. Waiting too long can lead to the mould spreading and causing more serious damage.

How does white mould affect the indoor climate?

White mould (Penicillium chrysogenum) can, in some cases, cause allergic reactions in sensitive people. This is known as mould allergy, which is a hypersensitivity to the particles that mould can emit when it grows and spreads. Mould allergy often occurs together with other allergies, which can make some people particularly susceptible.

According to some sources, prolonged exposure to damp environments with mould growth may be a factor in recurrent respiratory problems. Therefore, it is important to pay attention to signs such as bad odour or visible changes in spaces such as crawl spaces and basements.

Common symptoms of mould allergy

Symptoms may resemble common allergies or colds:

• Headache
• Hosta
• Respiratory problems
• Watery eyes
• Dry skin
• Fatigue

If you suspect that mould may be a contributing factor, you should first check moisture levels and inspect areas where growth may be present.

How to remove mould in the crawl space?

You can remove mould yourself by using Mould-free, an agent that is sprayed directly on the mould. You then let the product work and scrub blind bottoms properly. You can then use a UV lamp to check that you have removed the mould.

If there are still traces of mould, repeat the treatment. If the mould infestation is extensive enough, you need to do a more careful decontamination and replacement of damaged material to avoid impact on the structure of the building. If in doubt, consult a professional.

Prevent new infestations with a dehumidifier

• Once you have removed the mould, it is important to prevent new infestations. Start by removing all organic material, such as pieces of wood and other things that can provide food for the mould.
• Then plaster the ground and up after the edge beam to prevent soil moisture from seeping up and causing new problems.
• Seal all holes and gaps with sealing foam, so that no air from the surrounding environment can penetrate and increase humidity.
• Leave a valve open to allow you to bring out the dehumidifier's wet gas hose later, which helps keep humidity levels down.

Installing a crawl space dehumidifier

Simply sealing the crawl space is not enough - it can even make the situation worse if moisture is trapped. By installing a crawl space dehumidifier you can maintain a suitable moisture level all year round. With a dehumidifier, air is circulated and excess moisture is continuously removed.

This reduces the risk of new mould infestations and helps extend the life of your property. Another benefit is that you will often notice a difference indoors too - the floor will be warmer and the indoor climate more comfortable, especially during cold months.

Installing a crawl space dehumidifier is easy, and if you've already plastered the crawl space, you've done the heavy lifting. The rest is mostly wiring and placement.

💡 We're happy to help you size the right dehumidifier for your crawl space. Try our digital tools or contact us directlyand we will guide you.