Ask a tradesperson

Damp Proofing

Hi i have a problem with excessive condensation to the inner side of the bedroom bay window. in winter and when it is cold outside water runs off the windows.

There is also a light covering of mould on the wall paper which results in endless cleaning, ideas to find a solution would be appreciated. Many Thanks

4 Answers from MyBuilder Damp Proofing Specialists

Best Answer


I've dealt with this problem before. Basically this is caused by lack of circulation in your property. The moisture travels around the property until it find the coldest point "known as the dew point" where it settles to create condensation or mould.

Option are if you lock windows open, if possible this allows moisture to escape or fit electronic extractor fans in bathroom and kitchen with a sensor this should sort most of the problem.

Finally wash wall with watered down bleach to kill bacteria, paint with damp killer paint & re-paint.

Things to consider - every time you wash up, cook, bath/shower, wash clothes and hang clothes up they produce moisture. I think even we produce a ltr a day!

Any probs let me know



Answered 15th Oct 2013

Hi, I agree with the recommendations of the answers that are given for your problem. We have come across this problem many times where houses were built in 9in brickwork and the bay window support brickwork is built in 4in brickwork creating a cold wall. If this is your case, then add insulation to the 4in brickwork then plaster board and skim. This will warm the wall, vent the room with air bricks.


Answered 15th Oct 2013

Solution to condensation, the point when the warm air touches the cold surface and turns to condensation, is the saturation point. To prevent it, you need heating in the room, ventilation and air circulation i.e. air brick, make sure existing ones are not blocked, circulate the air by opening windows etc keep room warm


Answered 15th Oct 2013

Hi Autumn_20

During the period of October to March this is "Condensation Period". Condensation is sitting on your window because this is a cold zone and moisture has to go somewhere, so it will either go to corners of a room, behind units or as you're finding on your bay window.

Causes are washing on radiators, cooking, showers, family living, "breathing etc" and even a large dog can contribute to moisture in the air.

Remedy: Ventilation - do you have adequate ventilation in your bedroom and if not maybe have a basic vent fitted or go for a heat recovery system that will take out the stale moist air and reintroduce with fresh warm air.
If your room has poor or no heating this will add to the beading on the window.

Ventilation is the key.

Good luck and hope you have a mould and moisture free bedroom this winter.

Scott Cannon.


Answered 15th Oct 2013

Post your job to find high quality tradespeople and get free quotes

Can’t find an answer? Ask a new question

Question Categories