Mould and how to avoid it

How do properties get mouldy?

Damp

Mould grows in properties under damp conditions. Property damp can sometimes be cause by penetrating damp (rain water coming from outside), rising damp (groundwater seeping in) or plumbing leaks. By far the most common cause of damp, however, is condensation.

Condensation

Condensation is water that gathers on cool surfaces from moisture in the air. It occurs when the air in your property is warmer than the walls.

Student properties are particularly susceptible to condensation damp as they are densely occupied and often older constructions. A recent NUS survey reported 61% of students experience problems with condensation and mould in their housing.

Household condensation can make your property feel cold and reduce heating efficiency.

Worse, it provides the perfect habitat for MOULD to thrive. The problems with mould are:

• It produces allergens. These can worsen asthma, give skin rashes, sneezing fits, and cause you to suffer cold-like symptoms.

• It will make your clothes and property smell.

• It damages surfaces, clothes, books, curtains, etc.

• You might be charged for damage if you haven’t tried to manage it.

• Once it grows, it’s very hard to get rid of completely.

Avoiding condensation

1 Ventilate well by opening windows as often as is possible/safe. If you can’t avoid drying clothes indoors, make sure you open all the windows you can. Ensure any trickle vents on windows are always open, and make use of windows that are designed to lock slightly open.

2 Heating evenly throughout the property will prevent cold spots. Keeping the heating off, then turning it up high when you need it does not give walls time to warm up to prevent condensation from warmed air; it’s better to keep the property slightly warm at all times (more on this below).

3 Minimise moist air by thinking about the activities you do. Drying clothes on radiators is the biggest contributor to condensation damp, cooking (especially without lids on pans), showers and even breathing all add up. Make sure doors are closed on areas containing damp air, such as bathrooms, to prevent it spreading through the property before it is ventilated away.

4 Allow airflow behind furniture. Behind wardrobes is a favourite place for mould to lurk. Moving furniture a little away from the walls will prevent this.

5 Wipe away condensation from windows in the morning, and any mould you see. Sometimes mould will appear no matter how well you ventilate and heat your property. You need to wipe this away as soon as possible to prevent it breeding or staining. Bleach will not get at the mould’s roots – use a proper mould cleaning fluid, or check online for other methods.

Heating and ventilating consistently stops condensation

Keeping your heating at low levels consistently will prevent walls getting so cold that moisture condenses on them. 

Damp air comes from showers, drying clothes, cooking and even breathing. This damp air needs to be let out by opening windows.

The diagrams below demonstrate how to stop condensation damp occurring without paying for high bills. The arrows represent what happens to the moisture in the house.