Damp and mould

Damp can cause mould on walls, furniture and clothing. The presence of damp in your home encourages mould and mites and can increase the risk of respiratory illness.

Some damp is caused by condensation. This page explains how condensation forms and how you can keep it to a minimum to reduce the risk of dampness and mould.

Is it damp?

Damp can be caused by:

  • Leaking pipes, wastes or overflows
  • Rain seeping through the roof where a tile or slate is missing, spilling from a blocked gutter, penetrating around window frames or leaking through a cracked pipe
  • Rising damp due to a defective damp-course or because there is no damp-course

These causes of damp often leave a 'tidemark'. If you think your home is damp, please contact us and request that we visit you to check if this is the case. If you do not think the damp comes from any of the above causes then it is probably condensation. In which case, there are some things you can do to help prevent this.

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 the moisture and tiny drops of water appear. This is condensation. You notice it when you see your breath on a cold day or when the mirror mists over when you have a bath. Condensation occurs mainly during cold weather, whether it is raining or dry, and it does not leave a ‘tidemark’. It appears on cold surfaces and in places where there is little movement of air. Look for it in corners, on or near windows, in or behind wardrobes and cupboards. It often forms on north-facing walls. Here's some tips:

  • Do not block permanent ventilators
  • Do not completely block chimneys. Instead, leave a hole about two bricks in size and fit a louvered grille over it
  • Do not draught proof rooms where there is condensation or mould
  • Do not draught proof a room where there is a cooker or a fuel burning heater, for example, a gas fire
  • Do not draught proof windows in the bathroom and kitchen

How to avoid condensation

These three steps will help you reduce condensation in your home:

1. Produce less moisture. Some ordinary daily activities produce a lot of moisture very quickly:

  • Cover pans and do not leave kettles boiling
  • Avoid using paraffin and portable, flueless bottled gas heaters as these put a lot of moisture into the air
  • Dry washing outdoors on a line or put it in the bathroom with the door closed and the window open or fan on
  • Vent any tumble dryer on the outside, unless it is the self-condensing type. DIY kits are available for this

2. Ventilate to remove moisture. You can ventilate your home without making a draught:

  • Keep a small window ajar or a trickle ventilator open when someone is in the room
  • Ventilate kitchens and bathrooms when in use by opening the windows wider
  • Close the kitchen and bathroom doors when these rooms are in use - even if your kitchen or bathroom has an extractor fan this will help prevent moisture reaching other rooms, especially bedrooms, which are often colder and more likely to get condensation
  • Ventilate cupboards and wardrobes. Avoid putting too many things in them as this stops the air circulating. Cut a ventilation slot in the back of each shelf or use slatted shelves. 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

3. Insulate, draught proof and heat your home. Insulation and draught proofing will help keep your home warm and will also cut fuel bills. When the whole home is warmer, condensation is less likely:

  • In your loft, check that you have sufficient insulation. If you feel that the insulation is not sufficient then please contact us to arrange for an insulation survey
  • Remember to draught proof the loft hatch but do not block the opening under the eaves
  • In the winter, at night, make sure you close your curtains
  • In very cold weather, keep low background heating on all day, even when there is no one at home
  • Ensure that you know how to operate your heating effectively and ask us if you are unsure
  • Do not use your gas or electric fire as the primary heat source in your home as you need to heat all rooms with your central heating system

First steps against mould

  • First, treat any mould you may already have in your home. If you then deal with the basic problem of condensation, mould should not reappear
  • To kill and remove mould, wipe down walls and window frames with a fungicidal wash which carries a Health and Safety Executive approval number. Follow the manufacturer’s instructions precisely. Dry-clean mildewed clothes and shampoo carpets. Disturbing mould by brushing or vacuum cleaning can increase the risk of respiratory problems
  • After treatment, redecorate using a good quality fungicidal paint to help prevent mould recurring. Note that this paint is not effective if overlaid with ordinary paints or wallpaper