What is condensation and how to avoid it
There is always some moisture in the air, even if you cannot see it. When air becomes cold it can hold moisture and tiny drops of water appear. This is condensation.
You notice it when windows or mirrors mist up for example when you are cooking or taking a bath or shower.
Condensation occurs when temperatures drop mostly in the winter, whether it is raining or not. Unlike other forms of dampness it does not leave a tidemark. It appears on cold surfaces and in places where there is little movement of air, i.e. in corners of rooms, near windows, in or behind wardrobes and cupboards, it can affect clothes, shoes etc. as a result of mould growth.
There are two steps you can take which will help you to reduce condensation in your home:
Step 1: Produce less moisture
Some ordinary daily activities produce a lot of moisture very quickly. To avoid this the following action will help to reduce the risk of excess moisture generation.
Cover pans when cooking and do not leave kettles boiling
Avoid the use of paraffin and portable bottled gas heaters as these generate large quantities of moisture.
Dry washing outside whenever possible, do not dry wet clothes on radiators
Ensure tumble dryers are vented to the outside
Step 2: Ventilate to remove moisture
You can ventilate your home without making draughts:
Keep a small window ajar, ensure that trickle vents fitted in windows are open
Ventilate kitchens and bathrooms when these are in use by opening the window. If there is a humidivent fitted in these rooms ensure it is switched on and is fully operational. (Remember condensation forms when the temperature drops. Where humidivents are fitted they may operate during the night)
Close kitchen and bathroom doors when these are being used even if a fan is fitted. This will help avoid moisture reaching others rooms, especially bedrooms which may be colder and more likely to get condensation
Ensure cupboards and wardrobes are ventilated, avoid having too many things in them which will stop air circulating. Leave room at the back of wardrobes to allow air to circulate and place wardrobes etc. against internal walls.
Do not block permanent ventilators. This could make your Central Heating scheme dangerous.
Do not draught-proof rooms where condensation exists.
Do not draught-proof rooms where there is a cooker or fuel burner appliance i.e. gas fires
Do not draught-proof windows in kitchens and bathrooms.
If you do experience mould growth as a result of condensation you should:
- Treat mould you may already have in your home. If you then deal with the basic problem of condensation, mould should not then reappear
- To kill and remove mould, wipe down walls and window frames with a fungicidal wash, you should ensure that these products carry a health and safety approved number. Ensure that you follow the manufacturer's instructions precisely.
- After treatment, redecorate using a good quality fungicidal paint to help prevent mould recurring. Note: this type of paint is not effective if overlaid with ordinary paints or wallpaper.
The only lasting way of avoiding mould is to eliminate dampness.
Is it condensation?
Condensation is not the only cause of damp. It can also come from:
Leaking pipes, waste or overflows
Rain seeping through the roof where a tile or slate is missing, spilling from blocked gutters, water penetration around window frames or leak from a cracked pipe
Rising damp due to a defective damp course
The causes of dampness as a result of these defects often leave a "tidemark".