Condensation is caused when warm, moist air comes into contact with a cool surface. This is what happens when the bathroom mirror steams up.
Warm moist air is produced by normal household activities like cooking, washing and bathing.
Dampness caused by excessive condensation can lead to mould growth on walls and furniture and mildew on clothes and other fabrics which can all contribute to health problems, such as asthma and other respiratory disease.
Have I got damp or is it condensation?
- Is the problem on north-facing walls, in the corner of a room, in cupboards, behind furniture or under work surfaces? This is usually the result of condensation, where there is little air movement.
- Can you see water droplets on windows or water pooling on window sills? This is condensation.
- Can you see mould looking like black spots along the edges of your skirting or ceilings? This is condensation.
- Is there a clearly defined damp stain? This might be penetrating damp or a water leak – you need to report this to us.
- Can you see a ‘tidemark’ on ground floor rooms, extending to around 900-1000mm above the floor surface? This is uncommon and sounds like rising damp – you need to report this to us.
Easy ways to cut condensation
- Keeps lids on saucepans when cooking to reduce steam in the kitchen.
- Try not to dry clothes on radiators or rack indoors. If you have to do this, use the bathroom. Open a window to allow air to circulate and close the door to that room.
- If you use a tumble dryer, make sure it is vented to an open window or through an outside wall. Stop moisture spreading through your home. If your dryer has a built-in condenser, make sure that the filter is cleaned and cleared regularly.
- When you are cooking or bathing, use an extractor fan or open a window and keep the door closed. Keep the extractor fan on or the window open for about 20 minutes after you have finished (with the door closed).
- Leave trickle vents (the slotted vents in your window frames) open when rooms are occupied – even in the winter when your heating is on. These vents provide constant ventilation which removes water vapour.
- Don’t use paraffin or calor gas heaters.
- Leave a gap between your wall and the back of free standing furniture like wardrobes or cupboards. Try not to overfill cupboards, wardrobes and drawers so that air can circulate around the contents.
- When condensation appears, wipe it away. Ventilate moisture and wipe-away condensation.
- Use moisture traps, available from most DIY stores, in affected rooms for a big reduction in condensation.
Keeping temperatures constant
Keep your home warm to avoid cold surfaces.
Condensation is worse in buildings which are constantly heating and cooling. The temperature in your home should be between 18-24°C. Using your central heating thermostat to prevent the temperature dropping below 15°C can prevent condensation forming. If your home is unoccupied during the day, use the heating timer to make sure that the house is warm when you get home. During very cold weather it is better to leave the heating on during the day to keep temperatures constant. If you don’t usually use all the rooms in your home, you still need to keep them warm, to avoid cold spots.
How to get rid of mould
If you notice mould in your home, you should treat it straight away to stop it from spreading and causing damage.
- Sterilise the affected area with a suitable fungicidal wash (available from most DIY stores), following the manufacturer’s instructions.
- Keep checking the affected area for at least a week.
- If the mould returns, apply the antifungal wash again.
- When you have successfully treated the mould, you can redecorate. If you are wallpapering, choose a paste containing a fungicide to prevent further mould growth. A good quality fungicidal paint will also help to prevent mould.
- If mould or mildew is growing on clothing or carpet, you should dry clean them.
To prevent mould returning, make sure you control condensation in your home.