Condensation and damp

As the name suggests, condensation is water which has “condensed” from warm, moist air on contact with a cold surface. Air holds water in the form of water vapour. 

While it is not always visible, there is always some moisture in the air. It is noticeable when the mirror mists over after a shower, or when you see your breath on a cold day.  

When lots of condensation occurs in a build, mould may appear on cold external walls, around windows and in places where the air does not circulate well. It can be fairly common for it to appear in bathrooms and kitchens as the moisture levels will be high.  

Excessive moisture can damage clothes, furnishing and decoration. It can leave a musty smell. Severe condensation may exacerbate health problems like asthma, bronchitis, arthritis and rheumatism.  

A lot of everyday actions can produce water vapour. Given the amounts of vapour produced, it is important to know how to manage condensation. 

Below is an indication of the typical volumes of water produced by carrying out everyday tasks:

• Cooking = three litres
• Breathing/ perspiring = three litres
• Showering/ bathing = 1.5 litres
• Clothes drying = 1.5 litres
• Clothes washing = 0.5 litres

1) Stop moisture build up:  

• Wipe down surfaces where moisture settles  
• Cover boiling pans  
• Do not hang washing over radiators  
• Close bathroom and kitchen doors to prevent steam  

2) How to ventilate the home:

• When cooking or washing, open windows or extractors  
• When drying clothes inside, do so in small rooms with the windows open  
• Open windows for a while during the day or use trickle/night vents  

• Allow air to circulate around furniture and cupboards. You can do this by making sure cupboards and wardrobes are not overfilled and there is space between the furniture and wall 

3) How to heat the home:  

• Maintain a low heat when the weather is cold or wet as this is more effective than short bursts of high heat  
• Set your heating to provide warmth in all rooms, including those which are unused 
• Use thermostatically controlled radiator valves (where available) to control room temperatures  
• Avoid using paraffin or flueless bottled gas heaters 
• Use a dehumidifier if required  

Mould is a living organism which needs killing to remove. To do this: 

• Wipe down affected areas with fungicidal wash. Ensure that the cleaning product you use carries a Health and Safety Executive (HSE) approved number and always follow the manufacturer’s instructions for use and storage  
• Do not use bleach or washing up liquid  
• Cry clean mildewed clothes and shampoo carpets  
• Do not brush or vacuum mould as this releases spores into the air, increasing the risk of respiratory problems  

Not all damp is caused by condensation. Damp can also occur when a fault in a building lets water in from the ground or outside. Penetrative damp and rising damp are the two types to be particularly aware of.  

Penetrating damp occurs when water is coming in through the walls, roof or cracks. For example, it may travel under a loose roof tile, leaking pipe or waste overflow.  

Rising damp is relatively rare. The usual evidence of rising damp is a ‘tide mark’ on the walls that shoes how the water has risen up through the walls. If there are signs of rising damp in can mean that there is a problem with the damp proof course.  

If you suspect penetrating or rising damp in your property, inform your manager immediately.