Illustrated guide to condensation

This is an illustrated guide on how to deal with Condensation.

Damp can cause mould on walls and furniture and make window frames rot. Damp, cold housing encourages the growth of mould and mites. Mites feed on mould and both can increase the risk of respiratory illnesses in some people.

Some damp is caused by condensation. This leaflet explains how condensation forms and how you can keep it to a minimum, so reducing the risk of dampness and mould growth.

First steps against condensation

You will need to take proper steps to deal with the condensation, but meanwhile there are some measures you can take right away.

Wipe down the windows and sills every morning. Wring out the cloth rather than drying it on a radiator.

Condensation channels and sponge strips can be bought at DIY shops. They are fitted to windows to collect the condensation and thus help prevent window frames from rotting and avoid damp forming under the sills. Care must be taken to fit these devices properly.

First steps against mould

First treat the mould already in your home. If you deal with the basic problem, mould should not reappear.

To kill and remove mould, wipe down walls and window frames with a fungicidal wash which carries a Health and Safety Executive ‘approval number’.

Follow the manufacturer’s instructions precisely. Dry-clean mildewed clothes, and shampoo carpets. Disturbing mould by brushing or vacuum cleaning can increase the risk of respiratory problems.

After treatment redecorate using a good quality fungicidal paint to help prevent mould. Note that this paint is not effective if overlaid with ordinary paints or wallpaper. When wallpapering, use a paste containing a fungicide to prevent further mould growth.

The only lasting way of avoiding severe mould is to eliminate dampness.

Is it condensation?

Condensation is not the only cause of damp. It can also come from:

• Leaking pipes, wastes or overflows.
• Rain seeping through the roof where a tile
• or slate is missing, spilling from a blocked gutter, water penetration around window frames, or leaking through a cracked pipe.
• Rising damp due to a defective or missing damp-course or because there is no dampcourse. These causes of damp often leave a ‘tidemark’ and you should have the necessary repairs carried out to remove the source of damp. If your home is Council owned this work will be undertaken by the Council’s contractors. Contact the Maintenance Office to report any repairs.

If your home is newly built it may be damp because the water used during its construction (e.g. in plaster) is still drying out.

If your home is damp for any of these reasons it may take weeks of heating and ventilating to dry out.

Hiring a dehumidifier will help.

If you do not think the damp comes from any of these causes, it is probably condensation.

What is condensation?

There is always some moisture in the air, even if you cannot see it. If the air gets colder it cannot hold all the moisture and tiny drops of water appear. This is condensation. You may notice it when you see your breath on a cold day, or when the mirror mists over when you have a bath.

Condensation occurs mainly during cold weather, whether it is raining or dry. It does not leave a ‘tidemark’. It appears in places where there is little movement of air. Look for it in corners, on or near windows, in or behind wardrobes and cupboards. It often forms on north-facing walls.