Damp and mould advice for tenants

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 of the moisture in the air, even if you cannot see it.  If the air gets colder it cannot hold all of the moisture and tiny drops of water appear.  This is condensation. You can see it when you breathe on a cold day, or when the mirror mists over when you have a bath. Washing, people breathing, cooking and drying clothes are all things that put extra moisture into the air inside the house.  

An average family makes about 20 pints of water vapour in just one day. This vapour stays in the air in warm rooms but condenses back into water when it touches cold surfaces like windows or bathroom walls.

Why is condensation a problem?

The water formed by condensation can be damaging to your home and your health. Excess moisture encourages rot in wooden objects like doors and window frames and spoils decorations.  It can provide ideal conditions for mould especially mildew which causes black patches on walls and fabric. Some mould spores (the microscopic dust given off as a kind of seed) can be bad for your lungs. Condensation and damp can affect people’s health and may also damage internal decoration, clothes and furniture.

Is it condensation or damp?

It is important to be able to tell the difference between damp caused by condensation and damp caused by other factors such as rising damp. rainwater coming in, plumbing problems or poor drainage.

• Condensation tends to get worse in cold weather. The other types of damp (apart from plumbing leaks) tend to get worse in wet weather.
• Condensation tends to form patches of mould with blurred, soft edges rather than a stain mark.
• Condensation occurs when the air and/or surfaces are cold and when the moisture content of the air is high.
• Condensation mould tends to appear where there is little movement in the air for example behind wardrobes and cupboards.

Other causes of damp include:

• Leaking pipes, wastes or overflows rain seeping through the roof where a tile or slate is missing.
• Rising damp due to a defective damp course or because there is no damp course.

Where it can happen

Condensation happens most on the cool parts of walls, particularly on outside walls where there is not much air movement.  It often appears as a dark patch in corners near the skirting and on the ceiling.  The sidewalls of windows, are often affected, as they can be even colder.  Areas with poor ventilation can be prone to condensation.

How to avoid condensation

1. Produce less moisture 

• Cook with the kitchen door closed and the window open.
• Dry clothes outside if possible. If clothes are being dried inside, dry them in the bathroom with the door closed and the window open or fan on.
• In the bathroom always keep the door shut during use after use keep the door shut and open the window to let the steam out.
• Vent any tumble dryers to the outside, unless it is self-condensing.
• Cover pans and do not leave kettles boiling.
• Avoid using a paraffin or Calor gas heater to dry clothes.

2. Ventilate to remove moisture

• Where practicable keep a small window ajar or use a trickle vent when a room is being used.
• Airbricks have holes in them to help ventilation in the house.
• Make sure that air bricks and double glazing vents are clear.
• If you are blocking up a fire place, fit an air vent to the flue of the chimney.
• When using the kitchen or bathroom open the window wider. If possible use controlled fans in the kitchen and bathroom. These come on automatically and are cheap to run.
• Close the kitchen and bathroom doors when these rooms are in use. A door closer will help prevent moisture reaching other rooms which are often colder and more likely to get condensation.
• Ventilate cupboards and wardrobes and avoid over filling them as this stops the air circulating. Cut breather holes in doors and in the back of wardrobes and leave space between the back of the wardrobe and the wall. Where possible position wardrobes and furniture against internal walls.
• If new windows are installed make sure that they have trickle ventilators incorporated in the frame.

3. Insulate, draught proof and heat your home. (If you are in rented property you may have to ask your landlord if he can carry out the improvement works.)

• If your home has cavity walls, then you should consider having insulation injected into the walls. This must be carried out by an approved contractor.
• Secondary or double-glazing helps but is an expensive option. There are cheaper options for those who can manage a bit of DIY. Check your local store. You must ensure that on completion the room can still be ventilated easily.
• If you already have a simple extractor fan for your bathroom, consider fitting a time switch so that it will come on automatically. If it is connected to the light switch people will not forget to use it.
• Insulation in the loft (including the loft hatch) draught proofing of windows will help keep your home warm and you will have lower fuel bills as well. When the home is warmer, condensation is less likely.
• Check for slipped or missing tiles and slates and for damage to flat roof coverings.
• In cold weather keep low background heating on all day even when there is no one at home.
• Do not draught proof rooms where there is condensation or mould, as this will make the problem worse.
• Certain draught proofing work and window replacement requires building regulations approval.  Call Building Control on 020 8554 5000 for further advice.
• Make sure that the DPC is not covered by soil, (for example, raised flower beds).

4. Adequate heating in your home.

• Make sure your home is heated to a temperature of at least 21° C in the sitting room and 18° C in all other rooms.
• There are several organisations that can provide help and advice to ensure that your home has adequate heating and insulation to meet your needs.
• You may think that your home needs better heating and insulation, but you aren't sure who can help or how you can afford it. Maybe you want to know if you can get help with paying your fuel bills, or you want to make a complaint about your energy supplier. Whatever your need is, there are numerous organisations and schemes in place to help you.

Sometimes there are grants available to improve heating and insulation in tenanted properties.  If a grant were available your landlord would have to give permission for work to be carried out. 

How to prevent mould

• To kill and remove mould wipe down walls and window frames with a dilute bleach solution or fungicidal wash which carries a Health and Safety Executive “approval number”.  Follow the manufacturer’s instructions.  Dry clean mildewed clothes and shampoo carpets. Disturbing mould by brushing or vacuum cleaning can increase the risk of respiratory problems.
• Wipe away any surface moisture. If a paper towel is used for this purpose throw it away immediately.  If a sponge is used wring it out straight away to avoid the moisture being re-circulated.

After treatment redecorate using a good quality fungicidal paint to help prevent mould recurring. This paint should not be overlaid with ordinary paints or wallpaper.

Watch a video on how to treat damp and mould here. 

Further information for tenants in private rented accommodation

If you are a private sector tenant who, after following the advice contained here is still suffering from severe condensation, discuss the situation with your landlord. 

If your landlord is unwilling to help, contact:

Housing Standards Service

London Borough of Redbridge 

2nd Floor, Lynton House, 255-259 High Road, Ilford, Essex, IG1 1NY

Email: housing.standards@redbridge.gov.uk

Report a rental property online 

Further information for council tenants 

For more information please refer to our condensation advice leaflet (PDF 1.38MB) or call 0208 518 2400 if you are a council tenant.

If the problem persists, please contact our repairs contractor, Mears on 0800 393994 or 0208 498 8000 for further advice on how to resolve the problem.

You can also visit the council tenant repairs handbook page