Condensation is caused when moisture in the air makes contact with a cold surface and condenses into water. It is different to dampness, which is caused when water from the outside gets into the house, e.g through windows, doors or roofs.

You can avoid the problems of condensation by reducing the amount of moisture in your home. The following are the main causes of high moisture levels and in order to prevent condensation in your home you should avoid them:

  • Drying clothes on radiators
  • Unvented driers
  • Lack of ventilation in cooking, bathing or sleeping areas.
  • Lack of air flow (eg behind furniture)
  • Lack of space heating
  • Liquid or Calor gas heaters


The effect of condensation will usually be evident through windows misting or water forming on toilet cisterns. In more extreme cases condensation is apparent on walls or ceilings, where the effects may vary from marks on walls to black mould and deterioration of plasterwork.

If you find black marks or mould growth:

  • Wash down the affected surface with a mixture of five parts water to one part bleach and dry with a cloth. Repeat the process as necessary.
  • Ensure that you resolve the cause and provide a free flow of air, e.g. through more ventilation, especially in bathrooms and kitchens.


For more information please refer to our condensation advice leaflet (PDF 1.38MB) or call 0208 518 2400.

If the problem persists, please contact our repairs contractor, Mears on 0800 393994 or 0208 498 8000 for further advice on how to resolve the problem.

For tenants in council accommodation please visit the repairs handbook page

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