8.2 Condensation

Condensation normally occurs when warm, moist air drops in temperature. The ability of air to contain moisture depends on temperature. The higher the temperature the more moisture the air is able to contain. When the temperature of moist air drops – e.g. when it hits a cold surface – the air can no longer hold all its moisture and so some of it condenses into water droplets. This can occur from cooking, boiling kettles, steaming baths and showers, wet clothes etc… Condensation can take the form of water streaming down windows or dampness on walls, often associated with mould. Whatever the form, condensation is unhealthy and damages the building.

The following should be done as a matter of course even if there is no evidence of condensation.

• Do not turn off the whole house ventilation system which runs the fans in the bathrooms and kitchen. In order for the system to work it must be left to run continuously.
• Do not block any ventilation grilles.
• When drying clothes indoors, ensure that the windows in the room are open.
• If you turn off the heating in any room for any length of time, ventilate it by leaving a window open and keep the door shut.
• If there is water running down the windows or walls wipe them down and leave windows slightly open with the inside doors ajar or open.
• Cupboards and wardrobes can be ventilated by opening and closing the doors to circulate the air. Avoid putting too many things in them as this can stop the air circulation.
• Leave a space between the back of any further wardrobes that you install and walls, and if possible avoid putting wardrobes and large pieces of furniture against external walls.