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Is cavity wall causing damp exterior wall but no damp inside?

Hi I had fibre glass cavity wall installed 2 years ago by British Gas. I asked at the time if the fact that my gable end wall gets all the windy rain would be a problem - I live in Manchester not on a hill but the gable side does get heavy rain. Was told not a problem and that my pointing is in good condition (it is).
Never had any problems until 2 weeks ago and after a very heavy night of persistent rain the next day I noticed that my gable end (side of house) had a two tone brick effect. From top of house to the ground floor window level the bricks were darker and closer inspection saw the mortar was damp and the bricks also damp (but not wet to touch) since then it has been cold, no sun on that part of house and more heavy rain hitting the bricks. Bricks still darker as if damp and mortar is damp if I put a tissue on it.

My concern is that the rain has penetrating the brick hit the cavity wall installation material and this is now wet and not allowing my bricks to dry. Inside my house there is to date, no sign of any damp, wetness or cold walls.

Or is it that the bricks have just not dried out? Mine is the only house around me in this position to take the rain so can't compare

I am really worried about all this so any advice would be greatly received.

1 Answer from a MyBuilder Bricklayer

Best Answer

sounds to me like the wall just needs time to dry out, if there are no signs inside then it is not bridging the cavity via the insulation installed. all cavity wall insulation has to be repellent to water anyway. The cold weather is not helping at all. If you experience any damp inside, then there maybe cause for concern, otherwise try not to worry and give it time to dry. With the description you have given and the abuse this wall gets from the elements, I would look into having a brick sealing technique applied. This is clear and if applied correctly you will not know its there, it beads the water off yet still allows the masonry to breath.

Hope this helps.

James @ LP Design & Build Ltd


Answered 11th Feb 2014

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