Damp, mould and condensation

About damp, mould and condensation

Damp and mould in your home can cause health problems, including respiratory infections, allergies or asthma, and can affect the immune system.

Some people are more sensitive to others, including:

  • Babies and children
  • Older people
  • People with respiratory problems, allergies and asthma
  • People with an existing skin problem
  • People with a weakened immune system

If you experience damp and mould in your home, it's important that you deal with it as soon as possible.

Types of dampness

There are 3 main types of dampness:

  • Penetrating damp
  • Rising damp
  • Condensation damp

About penetrating damp

Penetrating damp is caused by water or moisture finding its way into your home when it shouldn't have, for example:

  • Through a leaking roof or gutters.
  • Through leaking pipework.
  • Through damaged or old brickwork absorbing water.

About rising damp

Rising damp damages plaster, wallpaper, paint and skirting boards. It's caused by insufficient damp proofing of external walls and internally rising groundwater saturating walls. 

You must treat the source of the rising damp before repairing the internal walls. A remedial Damp Proof Course (DPC) needs to be installed at the source of the problem.

If the source of the moisture is not from the ground, then the problem is not rising damp.

About condensation damp

Condensation damp is the most common form of damp and mould. It's caused by moisture created in the home.

Most people create at least 4 pints of moisture every day just from normal everyday activities, such as breathing, cooking, bathing, washing and drying clothes.

When temperatures drop, the air can no longer hold onto all the moisture generated in the home. The moisture will migrate to the coldest parts of your home and condense onto the windows and walls, and in places where there is little air movement.

How to spot condensation

There are a number of ways you can spot condensation in your home:

  • Streaming condensation starting to appear on windows and walls.
  • Damp areas starting to appear on walls, especially in corners and behind furniture.
  • The wallpaper starting to peel off the wall.
  • Black mould starting to appear around window frames, doors, walls and ceilings.
  • Soft furnishings and fabrics become prone to mould and mildew. This may be green or white in colour.
  • Constant musty smell in your home.

How to prevent damp and mould caused by condensation

There are some simple steps you can take to prevent damp and mould in your home, which include ventilating and heating your home properly so moisture doesn't build up.

You can also help prevent condensation if you:

  • Cover pots and pans when cooking, and turn the heat down once the water has boiled. Using lids can also save on gas and electricity bills.
  • Use extractor fans in kitchens and bathrooms.
  • Close internal doors when you cook or shower.
  • Run cold water first and then add hot water when filling a bath. This can reduce steam by up to 90 per cent.
  • Leave a gap between furniture and external walls.
  • Dry clothes outdoors, if possible, or use a condenser tumble dryer or a dryer which is vented to the outside. Don't be tempted to put wet clothes on radiators or in front of a radiant heater.
  • Open bedroom windows for 5-10 minutes when you get up.
  • Dry your windows and windowsills every morning, as well as surfaces in the kitchen or bathroom which have become wet. Wring out the cloth instead of drying it on a radiator.
  • Keep the temperature inside your home reasonably constant for as much time as possible. A healthy indoor temperature for a living room is 21 degrees Celsius. A healthy indoor temperature for a bedroom is 18 degrees Celsius.

How to remove damp and mould, and reduce the levels of condensation

You can remove damp and mould, and reduce the levels of condensation in your home, by:

  • Wiping down walls and window frames with a ready made mould-removing solution, or a solution of white vinegar in hot water. Do not mix different solutions together. 
  • Dry-cleaning mildewed clothes and shampooing carpets. Brushing or vacuuming can disturb the mould and increase the risk of distributing spores and causing respiratory problems.
  • Using a dehumidifier to control airborne moisture and help reduce the mould problem. However, dehumidifiers will not solve the cause of the condensation problem.

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