Condensation, damp and mould

Mould growth in the home can have a negative impact on health, especially for small children and those with respiratory conditions. It is therefore important to treat and prevent mould. Depending on whether you are a council tenant, private tenant or own your own home, sources of support will be different.

If you live in a council home, please raise a repair request online, call us on 020 8379 1000 (option 4, then option 2 for council housing repairs) or email

If you’re a private tenant or live in a home managed by a housing association, you should contact your landlord to fix the issue. If the landlord does not treat the mould, you can contact us for advice and assistance via our Private Rented Housing team at or telephone 020 3821 1761.

If you’re a homeowner, you can use the self-management advice below.

Some of the ways of preventing damp and mould in the home (such as ventilation and putting the heating on during cold weather) are very difficult to achieve at the moment given the cost of living crisis. Please see the sources of support available to residents on our cost of living pages.

Treating mould in your home

You can clean and treat small areas of mould growth safely yourself, using the method below:

Repeat this at the first sign of new mould growth, as well as wiping down any surfaces where moisture settles.

What causes condensation, damp and mould

There is always some moisture in the air. You may notice it when you see your breath on a cold day, or when the mirror mists over when you have a bath or shower. When the air is cold, it cannot hold all the moisture and tiny droplets of water appear. This is known as condensation.

Condensation occurs mainly during cold weather. It tends to appear on cold surfaces and in places where there is little movement of air, such as:

Condensation is usually the main cause of mould growth in homes. It usually becomes noticeable when black mould starts to appear on surfaces, such as window frames, walls, and behind cupboards and wardrobes. It is generally worse during the winter months.

Damp is usually caused by water entering your home from an external source, such as:

You can tell the difference between condensation and damp, as damp will normally look like there is a wet patch, or it will leave a white tide mark on the wall or ceiling surface. If you can check the outside of your home, you may be able to see the cause of the damp. Damp requires a different treatment solution to condensation, sometimes structural.

Preventing condensation

Everyday living activities, such as cooking, drying clothes in the house, and washing produce condensation. Preventing the build-up of condensation is essential for treating it in the long term, otherwise it can cause mould. The current high cost of energy use may make some of these solutions more difficult than previously.

High condensation levels can be prevented or reduced by following the steps below:

Council news directly to you

The latest news in your inbox every week. Council news, community updates, local events and more.

Sign up Sign up