Condensation Problems


It is important to bring condensation in a property under control as it can lead to major problems.

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If left unattended it can lead to problems which can cause serious damage to a home.
Condensation forms when warm moist air comes into contact with and condenses on cold surfaces.
Every home suffers from some condensation but much can be done to prevent it from building up and becoming a bigger problem.

If you have a condensation problem it can be controlled using the following methods:


  • Close kitchen and bathroom doors when in use even if they have extractor fans;
  • Cover cooking pans and do not leave kettles boiling - Prevents them producing warm moist air;
  • Dry washing outdoors or in a closed bathroom with a window open or fan on;
  • Externally vent tumble dryers or make them self-condensing;
  • Improved heating will always help with condensation problems - Set heating sources to give a low-level background heat ensuring there are no rapid temperature changes which cause condensation especially in extremely cold weather;
  • Improved ventilation - Open windows to help take damp air out of a property or ensure new frames have trickle ventilators;
  • Install a dehumidifier or humidistat-controlled electric fan - Both take moisture out of the air;
  • Install loft insulation - Remember to draught-proof the loft hatch but do not block openings under the eaves;
  • Install secondary or double glazed windows - Reduces heat loss and draughts but ensure there is some ventilation;
  • Ventilate cupboards and wardrobes - Avoid putting too many things in them as this stops the air circulating, cut ventilation slots or breather holes in backs and doors, leave spaces between them and the wall or position them against internal walls;
  • Ventilate kitchens and bathrooms, when in use by opening the windows wider.


The following should be considered when taking steps to prevent condensation problems:


  • Do not block permanent ventilators;
  • Do not completely block chimneys - Leave a hole about two bricks in size and fit a louvered grille over it;
  • Do not draught-proof rooms where there is condensation or mould;
  • Do not draught-proof a room where there is a cooker or a fuel burning heater such as a gas fire; 
  • Do not draught-proof windows in bathrooms and kitchens.


Condensation & Mould Control

What is condensation?

The amount of water (or water vapour) in the air will always vary with temperature. Basically the warmer the air is, the greater its water-holding capacity. In simple terms warmer air (i.e. when your central heating is on) holds more water vapour than colder air (i.e. on a night when the central heating is switched off)  and this will create condensation.

Air within a building is usually warm and can hold a considerable quantity of water vapour without there being any problems, however when it is cooled by contact with a cold surface (such as a window or external wall) or when your heating shuts down for the night, the excess water can no longer be held in the air as a water vapour and condenses as liquid water on walls, windows or other cold surfaces.

Condensation is one of the most common forms of dampness in residential buildings. It is mainly caused by warm, moist air from household activities such as cooking, washing, bathing, or even just breathing condensing onto colder surfaces in the home such as walls, window and ceilings.

From these activities alone, each person produces an average of four pints of water vapour a day. This means a family of five will produce approximately 20 pints a day, equating to 140 pints of water vapour a week. That can add up to be a lot of condensation.

This figure can be much higher if you:


  1. Use unvented tumble dryers or portable gas heaters;
  2. Dry clothing indoors or on radiators;
  3. Leave windows closed when cooking or having a bath or shower.

If you have condensation problems Damp Proofing London can help.



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Contact us today on:        077 0908 4010


020 8378 0089

Unit 55 Culvert Court, London, SW11 5AU