Damp and mould
If your home is damp it can cause mould to grow on walls and furniture and make wooden window frames rot. Damp also increases the risk of respiratory illness so it’s important that you take steps to deal with damp as soon as you notice a problem.
Causes of damp
Damp can be caused by -
- leaking pipes and overflows
- rain seeping through the roof where a tile or slate is missing, spilling from a blocked gutter or entering around window frames
- a defective damp course or because there is no damp course
These causes of damp often leave a ‘tidemark’. If you do not think your damp comes from any of these causes, then it is probably due to condensation.
Condensation usually occurs during cold weather and it does not leave a ‘tidemark’. It appears on cold surfaces and in places where there is little movement of air. Look for it in corners, on or near windows and in or behind wardrobes and cupboards. It often forms on north-facing walls.
You can reduce condensation in your home by following three simple steps -
Produce less moisture
- cover pans and do not leave kettles boiling
- avoid using paraffin and portable flueless bottled gas heaters
- dry washing outdoors, or put it in the bathroom with the door closed and the window open or a fan on
- vent tumble dryers on the outside, unless it is the self-condensing type. DIY kits are available for this
Ventilate to remove moisture
- keep a small window ajar or a trickle ventilator open when someone is in the room
- ventilate kitchens and bathrooms when in use by opening the windows wider or use a humidistat-controlled electric fan. They are cheap to run, and come on automatically when the air becomes humid
- close the kitchen and bathroom doors when these rooms are in use, even if your kitchen or bathroom has an extractor fan. A door closer will help prevent moisture reaching other rooms, especially bedrooms which are often colder and more likely to get condensation
- ventilate cupboards and wardrobes. Avoid putting too many things in them as this stops the air circulating. Cut a ventilation slot in the back of each shelf or use slatted shelves. Cut ‘breather’ holes in doors and in the back of wardrobes and leave space between the back of the wardrobe and the wall. Where possible, position wardrobes and furniture against internal walls
- if you replace your window units at any time, make sure the new frames have built-in trickle ventilators
Insulate, draughtproof and heat your home
- insulate your loft. Remember to draughtproof the loft hatch but do not block the opening under the eaves
- consider cavity wall insulation - you should talk to your local building inspector as building regulations approval is required.
- consider secondary and double glazing of windows to reduce heat loss and draughts but make sure there is some ventilation
- in cold weather, keep low background heating on all day, even when there is no one at home Some damp is caused by condensation.
To kill and remove mould, wipe down the 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.
The only lasting way of avoiding severe mould is to eliminate dampness.