main content Controlling Condensation and Mould

Condensation is a problem that can be remedied by ensuring that your property is ventilated, adequately heated and insulated. Minimising the amount of moisture produced in your property will also reduce the risk of condensation.

Details

There is always moisture in the air, even if you cannot see it. If air gets cold, it cannot hold all the moisture produced by everyday activities and some of this moisture appears as tiny droplets of water (condensation).

Condensation can appear on or near windows, in corners, on walls, often behind curtains and, in or behind wardrobes and cupboards. Condensation forms on cold surfaces and places where there is little movement of air. Excessive condensation can lead to mould growth in these areas.

Condensation doesn't leave a 'tidemark' round its edges on walls. If there is a 'tidemark' the dampness might have another cause, such as water leaking into your home from a plumbing fault, loose roof tiles or rising damp.

There are four main factors that cause condensation:

1. Too much moisture being produced in your home
Our everyday activities add extra moisture to the air inside our homes. The potential for condensation can be reduced by doing the following:

• Hang your washing outside to dry if possible, or hang it in the bathroom with the door closed and the window slightly open or extractor fan on. Don't be tempted to put it on radiators
• If you use a tumble dryer, make sure that it is vented to the outside or it is a condensing type
• When bathing or showing, keep the bathroom door closed with the window open or the extractor fan on
• If you use baby sterilizing equipment, ensure that you open a window when it is in use.

2. Not enough ventilation
Ventilation can hep to reduce condensation by removing moist air from your home and replacing it with drier air from outside:

• Ventilate your kitchen and bathroom when cooking or bathing, either by having a window slightly open or by using the extractor fan.
• If you have trickle vents in your windows, keep them open permanently
• 'Cross-ventilate' your home by slightly opening a small window upstairs and one downstairs. They should be on opposite sides of the house, or diagonally opposite if you live in a flat. This should be carried out for about 30 minutes each day.
• Be careful not to over ventilate as this will cause the temperature inside your home to drop and make condensation more likely.

Do not open windows if doing so would cause you a security problem.

3. Cold surfaces
Condensation forms more easily on cold surfaces and these can be made warmer by improving the insulation and draughtproofing. Loft and cavity wall insulation are the most cost effective forms of insulation. However, when installing draughtproofing, please remember:

• Do not draughtproof rooms with a condensation problem or where there is a heater or cooker that burns gas or solid fuel
• Do not block permanent ventilators or air bricks installed for heating or heating appliances
• Do not draughtproof kitchen or bathroom windows

4. The temperature of your home
Air is like a sponge; the warmer it is, the more moisture it will hold. Heating one room to a high level and leaving other rooms cold makes condensation worse in the unheated rooms. A short burst of high level heating only warms up the rooms air temperature. Low or medium level heating over a longer period will heat the air temperature and the fabric of the house, such as the walls. Once heated, the fabric will retain some of the added warmth, which in turn will reduce the time and amount of heat needed in warming up the room next time.

Heating controls, such as thermostats and timers, can be used to ensure you have adequate levels of heating in the right places at  the right times and this can also help to reduce heating bills. Keeping the heating on at low level all day in cold weather will help to control condensation.  

Contacts

Telephone: 020 8313 4830
Fax: 020 8313 4450
e-mail: housing.enforcement@bromley.gov.uk

Address: Housing & Residential Services, Civic Centre, Stockwell Close, Bromley, BR1 3UH