Tackling Dampness and Condensation

Here we explain how condensation forms and how you can keep it to a minimum, so reducing the risk of dampness and mould growth.

Is it condensation?

Condensation is not the only cause of damp.  It can also come from:

• Leaking pipes, wastes or overflows.

• Rain seeping through the roof where a tile or slate is missing, spilling from a blocked gutter, penetrating around window frames, or leaking through a cracked pipe.

If you do not think the damp comes from any of these causes, it is probably condensation.

What is condensation?

There is always some moisture in the air, even if you cannot see it.  If the air gets colder it cannot hold all the moisture and tiny drops of water appear.  This is condensation.  You may notice it when you see your breath on a cold day, or when the mirror mists over when you have a bath.

Condensation occurs mainly during cold weather, whether it is raining or dry.  It does not leave a ‘tidemark’.  It appears in places where there is little movement of air.  Look for it in corners, on or near windows, in or behind wardrobes and cupboards.  It often forms on north-facing walls.

How to avoid condensation

These four steps will help you reduce the condensation in your home.

1. Produce less moisture

Some ordinary daily activities produce a lot of moisture very quickly.

• Cooking: To reduce the amount of moisture, cover pans
• Paraffin and portable flueless bottled-gas heaters: These heaters put a lot of moisture into the air - one gallon of gas or paraffin produces about a gallon of water – so do not use this type of heating.
• Washing clothes: Put washing outdoors to dry if you can. Or put it in the bathroom with the door closed and the window open or fan on.
• If you have a tumble dryer make sure you vent it to the outside (unless it is the self-condensing type).  DIY kits are available for this.

2. Ventilate to remove the moisture

• You can ventilate your home without making draughts.
• Some ventilation is needed to get rid of moisture being produced all the time, including that from people’s breath. Keep a small window ajar or a trickle ventilator open all the time if possible, and especially when someone is in the room.
• You need much more ventilation in the kitchen and bathroom when cooking, washing up, bathing and drying clothes.  This means opening the windows wider and making sure your extractor fan in switched on.

3. Heat your home a little more

• In cold weather, the best way to keep rooms warm enough to avoid condensation is to keep low background heating on all day, even when there is no one at home.  This is very important in flats and bungalows and other dwellings where the bedrooms are not above a warm living room. If you have central heating set it to provide background warmth in all rooms including unused rooms.
• Remember to provide background ventilation at the same time.

Points to Remember

Produce less moisture:

• cover pans;

• wipe down windows and sills every morning

• dry clothes outdoors;

• vent your tumble dryer to the outside; and

• Do not use paraffin or flueless bottled gas heaters.

Ventilate to remove moisture:

• ventilate all the time, especially when someone is in;

• Increase ventilation of the kitchen and bathroom when in use and shut the door; and

• Ventilate cupboards, wardrobes and blocked chimneys.