Damp and Mould

4 min. readlast update: 03.02.2023

Damp and mould affect many UK homes periodically, particularly in the winter months. Modern living creates much more moisture and coupled with the addition of double glazing this creates the perfect breeding ground for damp and mould growth. What’s more, the UK climate has a high degree of seasonal variation with mostly mild weather conditions and then a few really cold months add to the problem. 

Excessive damp is unpleasant to live with and can lead to mould growth. It can cause discomfort and distress. It can cause damage to possessions, and to the building itself. If left untreated and it can be potentially harmful to health. It’s best to deal with damp as quickly as possible.  


This is the most common form of damp in UK homes. It occurs whenwater vapour (moisture) in the air meets a cold building surface and condenses. Moist air is a by-product of daily living. Showering, cooking, drying clothes and even breathing all contribute. Surface condensation appears when moisture within the air comes into contact with a cold surface, such as a window or a cold wall. 

To help avoid condensation mould developing, it is essential that occupants ventilate the space adequately to manage moisture levels and wipe away condensation as soon as possible.  

 How to manage moisture levels: 

  • Open windows regularly - let fresh air in and moist air out 
  • Check ‘trickle vents’ on windows if present - these should be open 
  • Windows (including velux windows) should have a position where they can be left secure, but very slightly open for ventilation  
  • Avoid a build-up of steam when cooking by putting lids on pans, and turn the heat down once the water has boiled 
  • Check mechanical extractor fans are working properly and use appropriately Keep kitchen and bathroom doors closed to prevent moisture escaping into the rest of the house 
  • Drying wet clothes indoors create a lot of moisture. Avoid leaving wet clothes / towels to dry indoors without adequate ventilation.  
  • Dry clothes outside or in a tumble dryer.  
  • Prevent damage to furnishings and possessions by leaving a gap between external walls and furniture / beds, etc if possible 
  • It takes a long time for a cold building structure to warm up, so it is better to have a small amount of heat for a long period than a lot of heat for a short time 
  • Whenever possible, it is best to keep heating on, even if at a low level 
  • Some rooms are especially cold because they have a lot of outside walls or lose heat through the roof 
  • Try to keep rooms at not less than 10°C at any time, in order to avoid condensation 


Moulds are a form of fungus. Mould spores thrive in moist environments, which is why occupants should try to prevent excessive moisture and adequately heat properties. When they land on a damp spot, with a supply of suitable nutrients, they begin to grow. Mould can grow on a variety of different surfaces, including fabric, paper, wood, glass, and plastic. Mould growth is usually visible and often produces a musty odour.  

Tackling Mould 

Regular cleaning and wiping can sometimes reduce the risk of condensation mould appearing or getting worse. As excess moisture and minor condensation mould is quite common (especially in colder months), occupants are usually expected to attempt to wipe it off when it arises. An example of this would be wiping down a window sill or bathroom wall where a small amount of mould had formed. 

 You can wipe hard surfaces with a suitable mould cleaner or fungicidal wash, carefully following the instructions. Dry surfaces well to prevent mould from reappearing. Porous surfaces can be washed but check regularly to see if mould has returned. If mould has infiltratedthe material it may need to be disposed of. There is a useful video with instructions here 


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