Condensation

Condensation can quickly become an issue in homes, especially in the colder months.
It’s a problem which is completely avoidable if the causes are understood. Ironically, modern housing construction with air-tight windows and doors is widely thought to contribute to condensation problems – as are modern lifestyle choices.

Stopping condensation is important because, if it is not treated, it can not only cause unsightly black mould to grow on your walls, curtains and upholstery – it can also cause damage to your property such as peeling wallpaper, damage to paint-work and timber rot.

Because the causes of condensation are completely within the control of the occupant of a property, responsibility for preventing it, and making sure it doesn’t cause any damage, also rests with the occupant.

What is condensation?

Condensation happens when moist air comes into contact with a cool surface. This is what happens when your bathroom mirror steams up. The glass mists up and drops of water run down the window or glass. If this happens on walls, the wall soaks up the moisture and becomes damp. Mould could then grow on the damp areas.

What causes condensation?

Even if you cannot see it, moisture is always in the air. In the home, moisture is particularly noticeable when we take a bath, shower, cook, wash and when we dry clothes indoors or use an un-vented tumble dryer. Bottled gas heaters also produce large amounts of moisture into the air. An average UK household produces 12 litres (20 pints) of moisture, per day, into the air in their home. This increases to 20 litres (36 pints) where clothes are dried indoors and where gas heaters are used.

Where does condensation occur?

Condensation is frequently found on or near windows, cold wall surfaces and in or behind cupboards or wardrobes. Moisture is often found in bathrooms and is easily seen on tiles. It is also found on the cool parts of walls, particularly on outside walls. Areas with poor ventilation are likely to hold moisture – behind furniture and beds on outside walls for instance.

Stopping condensation

In a nutshell, the way to stop condensation forming is by heating and ventilation.

8 tips to prevent condensation

During the Winter and at other cold times of the year you should try to maintain a constant temperature in your home. This is because it is cold surfaces that cause warmer air to release moisture. If your home is kept adequately heated then this cannot happen. Try to keep your home at a constant temperature rather than having large temperature differences such as heating on high during the day and turned off at night. Keep your heating on low throughout the day in cold weather.
Keep your home well ventilated by opening windows every day. This will allow any moisture from cooking, washing etc. to escape. You should also make sure that the trickle vents in your windows are open as these allow additional airflow that will help minimise condensation. If you have condensation on windows it is likely that it will be elsewhere in your property too.
When you’re drying your clothes you should dry them outside where possible. If you cannot do this then put them in a well ventilated room and keep the window open. Never place wet clothes directly on a radiator. If you use a tumble dryer to dry your clothes it’s extremely important that the ventilation pipe runs to outside your property.
During and after taking a bath or shower there will be excess moisture in the air. To stop condensation forming, the bathroom windows should be opened and extractor fans turned on. Try to keep the bathroom door shut as much as possible while using the room so the moisture doesn’t escape into other parts of your home. When you’ve finished, ventilate the room fully.
If you have extractor fans in the kitchen, turn it on while cooking. This will extract any excess moisture from boiling pots and pans. If possible, open up the kitchen windows whilst cooking for extra ventilation. It’s an idea to leave the extractor fan on for longer than you are cooking as there will be excess moisture in the air which you cannot see.
Always keep the lids on pots and pans whilst cooking so that the moisture doesn’t escape from the pans and avoid leaving anything on the boil for too long. If the lids are off, moisture will be rising from the pans even if you cannot see it. Just as you can only see your breath in the air on a cold day, you can only see the moisture rising from a pan when the temperature is lower.
You should leave a small gap between the walls of your home and your furniture as this allows the air to move away from the bottom of the walls and circulate around the room. If air lingers between the furniture and walls it will condense onto walls and could eventually form into black mould.
You should ensure there is good air circulation around your home. Air circulation is extremely important as you don’t want moist air to be trapped in one part of your home as it will condense on your walls. Your property’s airways such as air-bricks and chimneys should be clear to allow airflow in and out of your home.

Dealing with mould growths

To remove and kill mould, wipe down or spray walls and window frames with a fungicide solution, ideally with Health and Safety Executive approval. These are readily available in most supermarkets.
Wipe the area again every few days to stop the mould growing back
Dry clean mildewed clothes and shampoo carpet. Do not try to brush or vacuum the mould away.