Condensation & Mould Growth
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.
How to avoid condensation
These four steps will help you reduce the condensation in your home.
Produce less moisture:
• Cover pans when cooking and do not leave kettles boiling
• Dry clothes outdoors
• Vent your tumble dryer to the outside
• Avoid using paraffin or flueless bottled gas heaters
Ventilate to remove moisture:
• Ventilate all the time, especially when someone is in
• Increase ventilation of the kitchen and bathroom when in use and shut the door
• Ventilate cupboards, wardrobes and blocked chimneys
Insulate and draughtproof:
• Insulate the loft
• Draughtproof windows and external doors
• Consider cavity insulation
• Consider secondary glazing
• Find out if you are eligible for a grant or other help
Heating the House
• If possible, keep low background heat on all day, with background ventilation
• Find out about benefits, rebates and help with fuel bills
Treating Mould Growth
• First treat any mould you may have in your home. If you then deal with the basic problem of condensation, 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 recurring. Note that this paint is not effective if overlaid with ordinary paints or wallpaper.