Condensation can cause dampness and mould growth in your home. Mould and condensation can have a detrimental effect on internal materials and in some cases cause health issues.
Here are some frequently asked questions on damp and mould.
It is not always easy to tell but here are some key differences between condensation and other forms of damp.
Condensation is usually found on north facing walls and in corners, in cupboards and under work surfaces – in fact wherever there is little air movement.
Other kinds of dampness, such as rain or plumbing leaks, usually leave a ‘tidemark’.
Condensation can often be characterised by mould growth – mould generally grows on cleaner water so is unlikely to grow on moisture from penetrating or rising damp.
If you are not sure what is causing the damp in your home, start by checking pipes and overflows and under sinks to see if there are any obvious leaks. Have a look outside, too – you may be able to see if there are slates missing from the roof or cracked gutters or rainwater pipes.
If you live in a new or recently modernised house or flat, don’t forget that it may not have dried out from the water remaining after the building work. It usually takes 9 to 18 months for this to happen and you may need to use more heat during that time.
Every home gets condensation at some time – usually when lots of moisture and steam are being produced, for instance at bath-times, when a main meal is being cooked or when clothes are being washed. It is quite normal to find your bedroom windows misted up in the morning after a cold night.
Air can only hold a certain amount of water vapour – the warmer it is the more it can hold. If air is cooled by contact with a cold surface such as a mirror, a window or even a wall, the water vapour will turn into droplets of water-condensation. So the warmer you keep your home the less likely you are to get condensation.
For mould growth to occur there needs to be a sufficient amount of water available, this is why mould growth often occurs with condensation or dampness. This type of mould looks like “black spots” and is typically found along skirting boards or ceiling edges.
If your home is damp or has lots of condensation, the chances are the house will be a cold house. Living in a cold house may lead to negative health effects. Therefore it is important to keep your house warm.
Mould produces tiny spores which can cause an allergic reaction and make existing breathing problems worse. However house dust mites are the most common triggers of asthma rather than mould growth. House dust mites thrive where the amount of ventilation is reduced, warmer indoor temperatures and high humidity. These conditions can also lead to condensation.
To kill and remove mould, wipe down or spray walls and window frames with a fungicidal wash that carries a Health and Safety Executive (HSE) 'approval number', and ensure that you follow the instructions for its safe use. These fungicidal washes are often available at local supermarkets. Dry-clean mildewed clothes, and shampoo carpets. Do not try to remove mould by using a brush or vacuum cleaner.
After treatment, redecorate using good-quality fungicidal paint and a fungicidal resistant wall paper paste to help prevent mould recurring. The effect of fungicidal or anti-condensation paint is destroyed if covered with ordinary paint or wallpaper.
The only permanent cure is to reduce the amount of condensation in your home. Remember, the way you use your home affects the amount of condensation you get. This does not mean that you should alter your habits drastically.
You will get less condensation if you keep your home warm most of the time. This is not easy with fuel prices so high, but try to remember the following:
Heating one room to a high level and leaving other rooms cold makes condensation worse in the unheated rooms. Try to leave some background heat on through the day in cold weather. Most dwellings take quite a long time to warm up, and it may cost you more if you try to heat it up quickly in the evening. If you don't have heating in every room, you could keep the doors of unheated rooms open to allow some heat into them.
To add extra heat to rooms without any form of heating, it is better to use electric heaters, for example oil-filled radiators or panel heaters, on a low setting. Try not to use portable bottled gas heaters in homes suffering with condensation as they give out a lot of moisture whilst in use. Contrary to popular belief, it is actually cheaper to heat a room with on-peak electricity than by bottled gas heaters.
Don't use your gas cooker to heat your kitchen as it produces moisture when burning gas. (You might notice your windows misting over).
Drying clothes indoors, particularly on radiators, can increase condensation unless you open a window to allow air to circulate. Up to 9 pints of excess water can be produced by drying your clothes inside. Hang your washing outside to dry if at all possible, or hang it in the bathroom with the door closed and a window slightly open or extractor fan on. Don't be tempted to put it on radiators or in front of a radiant heater.
If you have a tumble dryer which is not vented to the outside you will need to allow more ventilation when you use it.
When filling your bath, run the cold water first then add the hot - it will reduce the steam by 90% which leads to condensation.
Don’t overfill cupboards and wardrobes. Always make sure that some air can circulate freely by fitting ventilators in doors and leaving a space at the back of the shelves.
Never block these up completely. If you are blocking up a fireplace, fit an air vent to allow ventilation.
Keep kitchen and bathroom doors shut, particularly when cooking, washing or bathing – otherwise water vapour will spread right through the house and condensation will probably reach other rooms.
The more moisture produced in your home, the greater are the chances of condensation, unless there is adequate ventilation. Nobody likes draughts, but some ventilation is essential.
Help to reduce condensation that has built up overnight by opening to the first notch a small window downstairs and a small window upstairs. (They should be on opposite sides of the house, or diagonally opposite if you live in a flat). At the same time, open the interior room doors, this will allow drier air to circulate throughout your home. This should be carried out for as long as possible each day.
Ventilate your bedroom by leaving a window slightly open at night, or use trickle ventilators if fitted.
Reduce the risk of mildew on clothes and other stored items, by allowing air to circulate round them; Remove “false” wardrobe backs or drill breather holes in them; Place furniture on blocks to allow air to circulate underneath; Keep a small gap between large pieces of furniture and the walls, and where possible place wardrobes and furniture next to internal walls instead of external ones;
Pull shelves away from the backs of wardrobes and cupboards; never overfill wardrobes and cupboards as it restricts air circulation.
Don’t allow kettles and pans to boil away any longer than is necessary.
Always cook with pan lids on, and turn the heat down once the water has boiled. Only use the minimum amount of water for cooking vegetables
• Try to reduce the amount of moisture you produce
• Improve ventilation in your home
• Try and maintain an adequate temperature throughout your home