There are three main causes of damp and mould within properties. These are:
- Penetrating damp
- Rising damp
Condensation is by far the most common cause of damp and mould within properties, particularly during the winter months.
Condensation starts as moisture in the air caused by cooking, washing, drying clothes on radiators and even breathing. When this moisture hits a cool surface such as a window or wall it condenses and forms water droplets which creates the right environment for mould to grow.
How to reduce condensation in your home
Control excess moisture
- Close kitchen and bathroom doors to prevent steam going into colder rooms
- When cooking or washing, let the steam escape by opening a window or using an extractor fan if you have one fitted. Leave the window open or the extractor fan on for up to 20 minutes after you have finished cooking or washing
- Open some windows in other rooms for a while each day and open any trickle vents in your window frames. This allows a change of air
- Wipe down surfaces when moisture settles to prevent mould forming
- Do not block air vents and allow air to circulate around furniture and cupboards
- You must not use bottled gas or paraffin heaters – these produce a lot of moisture and they are also a health and safety risk
Produce less moisture
- Dry clothes outdoors whenever possible or use small ventilated rooms
- Cover fish tanks and remember that house pets and plants produce moisture as well
- Cover pans when cooking
- If you have a tumble dryer or washing machine ensure that it is vented in accordance with the manufacturers instructions
Keep your house warm
Insulation and draughtproofing will keep your home warmer and will also cut fuel bills. When the whole house is warmer condensation is less likely to form.
- Insulating your loft and walls will help
- Maintain low background heat when the weather is cold or wet
- Consider installing secondary double-glazing of windows to reduce heat loss and draughts. If you wish to do this you must make sure that there is some ventilation in the room
- Do not block permanent ventilators
- Do not completely block chimneys. Leave a hole about two bricks in size and fit a louvered grille over the opening
- Do not draught proof rooms where there is condensation or mould growth
- Do not draught proof a room where there is a gas cooker or a fuel-burning heater, for example a gas fire
- Do not draught proof windows in the bathroom or kitchen
- Do not put furniture against cold external walls
This occurs when there is a defect with the fabric of the building or services within it allowing water to enter the property. For example a roof leak, disrepair to window and/or door frames or a leak from a waterpipe within the property.
Penetrating damp can usually be identified by water staining, usually yellowy brown in colour, in a particular area where the water is entering the property. The location of this staining is generally an indication of the source of the leak/water penetration.
Rising damp is caused by the breakdown, deterioration or bridging of the damp proof course of the building. Moisture then rises up the walls to a maximum height of 1 metre.
As with penetrating damp, it can be identified by a tide mark which can be yellowy brown or can be white and textured. This texture is caused by salts from the ground and the plaster being drawn through the wall with water.
You can download an information sheet for preventing damp and mould in your property by following the link below.
Damp and Mould guide