Damp, mould and condensation advice

All air contains water vapour. The warmer the air is, the more water it contains. When air comes into contact with a surface that is colder, the water vapour turns into droplets of water (condensation). 

Every household suffers from condensation, usually when moisture and steam are being produced. We even produce water vapour during our sleep as we breathe - we create about half a litre of vapour every night. This is why bedroom windows mist over during a cold night. In areas where condensation occurs regularly, surfaces can stay damp for a long time, which is when mould can begin to grow.  

Condensation is not the same as damp. Both can cause mould to grow on walls, which is why they are often confused – but the way to deal with them is very different. 

Problems can occur as a result of rising or penetrating damp. These are usually identified by a tide mark at the edge of the area of damp. 

Rising damp is caused by a failed or ‘bridged’ damp-proof course that allows moisture in the ground to rise up through the ground floor walls. 

Penetrating damp is usually caused by:  

  • overflowing pipes or gutters  
  • holes in the roof  
  • cracks in walls,  
  • poor brickwork. 

Mould growth can be caused by condensation and usually forms on decorative surfaces, especially wallpaper. It can cause severe and permanent damage. Mould and its spores create a musty odour and can sometimes cause health problems. Black mould can only grow in the pure water associated with condensation, it is not a sign of rising damp. 

Dealing with Mould 

Mould can be washed off walls using a special fungicidal wash. Special paints can help prevent mould returning, but you will need to take further steps to stop it completely. 

  • Don’t leave kettles or saucepans boiling for longer than necessary and put lids on pans
  • When you’re cooking or bathing - close kitchen and bathroom doors and open the windows or use an extractor fan
  • Avoid drying clothes indoors unless you have extra ventilation
  • Put some cold water into the bath before filling it with hot water to reduce the amount of steam you create
  • Make sure tumble driers are vented to external air. Remove any moisture that is produced 
  • Keep your home warm and well ventilated 
  • Don’t overfill cupboards or wardrobes 
  • Don't stand items of furniture against the wall. Leave enough room for air to circulate 
  • Dehumidifiers can help, but they only work when the house is warm and damp, not cold and damp - they are expensive to run
  • Check your heating system regularly to keep it running efficiently
  • Extra insulation helps reduce condensation, energy usage and saves you money
  • Close the curtains at night and, if possible, open a window or Trickle vent slightly for ventilation

If you need help or advice, please contact us