Condensation, damp and mould

Everyday things like cooking, washing, bathing and even breathing cause moisture, which is released into the air. The air can only hold a certain amount of water vapour - the warmer it is, the more it can hold. If this is cooled by contact with a cold surface such as mirror, a window or even a wall, the water vapour will turn into droplets of water - condensation. This is what happens when the mirrors mists up in the bathroom.

It is quite normal to find your bedroom windows misted up in the morning after a cold night. This does not mean there is a serious condensation problem.

If your home never seems to be free from condensation, or you have mould growth as well, the good news is that most problems with condensation and mould can be sorted out quickly if you reduce the moisture in the air, find where mould is growing and clear it away properly.

Mould can grow on any surface, so if you spot any mould it’s important to take early action as it can spread quickly.

Mould can typically be found on or next to windows, in the corners and edges of rooms, and behind and inside wardrobes and cupboards (especially if they’re against an outside wall).

New build homes take time to dry out.

Condensation comes from water in the materials used to build your home and it takes on average around 12 months for a new build home to fully dry out. During this time there is higher chance of mould growth because moisture levels inside your home will be higher than usual. New homes are designed to be well insulated and air-tight to meet current building regulations so it’s harder for warm air and moisture to escape.

New build homes need good ventilation and gentle heating to prevent damp and mould issues, especially during the colder months. Mould growth in a new build property is unlikely to be accepted by the builder as a defect and so it is important that you reduce condensation in your new home.

For more information, see the ‘Moisture in new homes - a guide for occupants’ on the NHBC Foundation website.

Produce less moisture

• Dry your washing outside whenever you can. If you dry clothes inside hang them in the kitchen or bathroom, but keep the door closed and the window wide open or an extractor fan on.
• Don’t put wet clothes on radiators – using a drying rack is much better.
• Never use portable gas bottles or paraffin (flueless) heaters.
• Permanently vent your tumble drier to the outside of your home, using a suitable kit recommended by the manufacturer.
• While cooking, always cover pans and don’t leave kettles boiling.

Improve ventilation

• When a room is in use, keep a small window and/or trickle vent open.
• Ventilate bathrooms and kitchens regularly.
• Keep bathroom and kitchen doors closed even if they have extractor fans.
• Ventilate cupboards and wardrobes – do not overfill wardrobes. If possible, locate wardrobes against internal partition walls.
• Leave a gap between the furniture and walls so air can circulate.

Insulate and heat your home

If your home is not sufficiently heated, you’re more likely to have issues with condensation. Keeping your home warm with insulation, draught-proofing and heating reduces the risk of condensation.

• Keep your heating at a steady temperature (18-21c). Find a setting that gives you the heat you need without increasing your heating costs.
• If you have thermostatic radiator valves, put them at a lower setting in rooms you don’t use much, but don’t switch of heating entirely.
• Avoid using alternative heat sources such as paraffin heaters, these can create more moisture into the air.

• Wear protective gloves and a face mask, along with old clothes that you don’t mind throwing away.
• Open windows in the room you’re cleaning and shut the door.
• Use a domestic cleaning product or mould remover – you can buy these from supermarkets and DIY stores. Carefully follow product guidance and safety instructions.
• Some natural products can be used to tackle mould. It is always best to do your own research into this.
• After clearing the mould, clean all surfaces by wiping down with a wet cloth to remove any spores that may have spread, then dry the surfaces. Redecorate using a good quality fungicidal paint.