The most common form of damp is caused by condensation. Condensation occurs when warm air comes into contact with a colder surface such as a wall, window, mirror or when there is too much humidity in your home.

Condensation is chiefly a winter problem, as the external air temperature is low causing walls and windows to be cold, in contrast, air within the property is warmed by central heating and daily activities such as cooking and showering. When this moist air comes into contact with a chilly surface, it cools down quickly and releases the water it was retaining, causing tiny drops of water to appear on the surface.

The areas in which condensation most commonly takes place are

  • Walls and windows in kitchens and bathrooms, where atmospheric moisture levels are usually highest
  • Solid external walls
  • Un-insulated solid floors
  • Cold bridges, such as concrete lintels set in cavity walls

If condensation isn’t dealt with immediately it can go on to encourage mould to start growing on your walls, ceilings, and around your windows and lead to a deterioration in the decorative condition of the property through stained curtains, decayed window frames and fungal decay in floor timbers. As well as causing a number of health issues.

Signs of damp caused by condensation

You can identify damp caused by condensation by looking out for the following signs :

  • Black Mould
  • Excess water collecting on windows
  • Peeling paint or plaster
  • Mould on clothes or fabrics
  • Unpleasant, musty smells


When treating damp caused by condensation, simply heating the air is unlikely to be a satisfactory solution, not only on grounds of cost, but also due to practicality. Unless cold surfaces are eliminated, condensation is almost inevitable. Any remedial action, therefore, must involve both a lowering of moisture levels and the elimination of cold surfaces.

When condensation is a persisting problem, it is advisable to contact a specialist surveyor to explore the cause of the problem and provide expert advice or propose solutions

We have listed just a few of the possible methods of controlling condensation below

  • Improved heating and ventilation coupled with specific action in relation to cold spots will usually result in a significant improvement in conditions, although there may be circumstances in which alternative methods are required. A modest but constant background heat is preferable to intermittent heating since this will help to maintain a higher ambient temperature in the fabric of the building.
  • The installation of a small extractor fan in a kitchen or bathroom will carry away moisture-laden air from the two areas most responsible for condensation with minimal running costs. This is now also required by the Building Regulations in new constructions. Extractor fans which incorporate a humidistat, which will control the operation of the fan within certain humidity limits are now available. It is also possible to install fans that have an integrated heat exchanger. These have the advantage of providing effective ventilation whilst reducing heat loss from the property.
  • Where an open fire or fixed gas fire exists, a certain amount of “natural” ventilation will occur and where additional ventilation is provided, it is important that this is not blocked off.
  • The use of specialist insulation materials fixed to the outside of the building and insulation in cavity walls will help to improve the thermal dynamics of the building and may help overcome condensation.
  • An alternative to heating and ventilation for the control of moisture in the air is a dehumidifier. This is a device which draws in air, cools it to remove moisture which is collected in a reservoir and reheats it to an acceptable temperature before re-circulating it.
  • Other devices that may be considered are positive pressure condensation control units. These often take dryer air from roof spaces or lofts and mix this with air in the dwelling. This is done at a very low rate (below half an air change per hour) and has the effect of lowering total moisture content and removing moist air by natural leakage.

If you suspect or have identified that you have a damp issue relating to condensation and need it resolved, then call Damp Zone today on 0121 690 1111.

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