What is condensation?

Condensation is caused when warm moist air hits a cold surface such as a window or external wall.

The warm air turns to water and can run down the cold surface. If left, this can develop into black mould which can cause damage to decoration and furniture and can cause health problems.

The following can cause condensation in your home:

• Drying clothes indoors
• Lack of air circulating in the house
• Steam from cooking or bathing
• Moisture from breathing

Dealing with black mould

Mould is a living organism and needs to be killed in order to get rid of it. To do this, apply a fungicidal wash (such as a mould and mildew remover) to the affected area. Fungicidal paint can be effective in reducing mould growth.

What is damp?

Damp occurs when a fault in the building basic structure lets water in from the outside. There are two different types of damp.

Penetrating Damp

Penetrating damp occurs when water enters the property through the walls or roof. This may happen because of loose roof tiles, cracks in the walls, overflowing guttering, damaged render or badly fitting windows/doors. Signs of penetrating damp are blotchy, stained patches on walls, wet and crumbly plaster.

Rising Damp

This is caused by a failed damp proof course. This allows moisture in the ground to rise up through the ground floor walls of your home sometimes to a height of one metre. You can usually identify rising damp because it is often seen as a ‘tide mark’ near the bottom of the affected walls.


Condensation is most likely to be a problem in homes which are under heated. Try to keep all rooms heated above 15°C.


Insulating your home will warm the surface temperature of walls and windows, generally increasing the temperature of the home.

Ventilate to remove moisture

Make sure vents aren’t blocked up and use an extractor fan when cooking. Open trickle vents on windows or keep a small window ajar. Don’t position large items of furniture too close to a wall as this reduces air circulation.

Produce less moisture

Condensation occurs when there is too much moisture in the air. Dry clothes outside where possible, don’t dry clothes on radiators, close doors whilst cooking or bathing, put lids on pans when cooking.

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