Damp Proofing Question

Condensation in bedroom and damp mainly underneath window sill area

I moved into a 1930's house 2 years ago and have damp issues around certain areas of the property, mainly internally on external walls around windows and doors. The main concerns are black mold underneath windows and in between the windows in behind where the curtains hang. I sometimes find my breathing becomes irritated when the problem is worse in winter.

I had a fella out to do a 'survey' but he never actually did anything other than look at the pebble dash render outside, despite me telling him my main problem was on the kitchen wall which is not pebble dashed. He suggested pulling off the old render from the entire house, applying new render, along with timber treatment, and tanking the entire ground floor of my large(ish) detached house. Condensation only occurs in the room we sleep in and the damp is mainly underneath the window sill area, however the box room external wall is always cold and damp with mold growth and smells awful and when peeling the paper off recently we discovered there was a silver lining underneath the wallpaper.

I suppose my question is, do you think I need all the work (he quoted me £15k!) or do you think I have a ventilation issue? I am a pain for having the heating on in autumn/winter as I am always cold, but I do leave windows open in the problematic rooms. I don't have a bathroom extractor fan fitted, but my bathroom is not one of the affected rooms.

I just don't know whether I need to rip up all my new flooring and pull my kitchen out for the tanking if I don't actually need it!

Thank you in advance.

Thanks for your great replies! I did think it was a bit of an exaggeration on his part. The only thing about the tanking is that the back internal kitchen wall that is really bad with condensation is below the the external ground level by a few inches, can we just get the kitchen area in the affected place done or should we do the whole room?

I really do appreciate the feedback :)

3 Answers

Best Answer

Hi there
This is a condensation problem, the best thing is better air circulation air bricks or fans, alternatively you could dot and dab the external walls with polystyrene backed boards to raise the temperature of the wall stopping the moisture from reaching the dew point where it condenses and then helps form the black mould.
Keep bathroom/kitchen doors closed when in use and after and do not dry clothes on radiators.
As for the quote for tanking and hacking off render all sounds like a con to me, tanking is used for stopping penetrating damp where the ground levels externally are higher than the internal levels like in a basement.

Answered 8th Oct 2013

Trident Damp

Member since 26 May 2011

Don't think what has been suggested will resolve the problem; replacing the render won't change things unless it's blown and cracked, and water is easily traversing through. Tanking the ground floor only stops rising damp - this is not the problem.
Interesting that you don't have the radiator under the window.
You are ventilating the room which is good but maybe too much in that your lossing all the benefits of the heating system and costing you money; consider having trickle vents installed in the window frames.
From what you have described I feel the house is poorly insulated; I would consider removing the internal plaster and dry lining with insulated backed plaster board, you will lose a bit of floor space but you will get the benefit of a warmer house. But do make sure there is some form of trickle vents either through the window frame or air brick with hit & miss louvres. Maybe also replumb radiators so they are positioned under window cills as well.
Hope that helps

Answered 9th Oct 2013

JLM Architecture Limited

Member since 5 Sep 2013

Humidifier. To dry out.
Not to expensive. ...

Dirty wall ties in these areas
Lifton windowseal internal inspect wall ties to damp area

Answered 11th Feb 2018

DJA Building Services

Member since 17 Nov 2017

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