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Cavity Insulation

We had our cavity insulation done about three years ago, iirc, and we've just noticed something worrying.   The installers inject basically chewed up paper, don't they, and make one helluva row in the process!   We've just noticed the odd patch of damp on our walls.   It has been suggested to us that the stuff that is injected into the walls is itself damp so as to be malleable and could possibly attract more moisture.  Does anyone know if that's true?  Has anyone else noticed a problem?


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Hugh J
Faulty pointing can cause this problem particularly on windward walls. The slightest leak can cause big problems. Cavities when unobstructed drain leakage of the outer wall. Insulation mops it up and holds it.
Ann P
Many thanks , Hugh.  Actually, it is a windward wall that's worrying us, but the boss reckons the pointing's just fine.  Just supposing he's mistaken, is there anything we can do about it?
Hugh J
I am not an expert at fixing these things. Perhaps you should speak to a building surveyor. Do you have little pets? Sand Wasps perhaps? Also, look for poor quality porous bricks. Sorry I am not much help.
John H
Also if there are any gaps in the insulation (due to an obstruction between the walls) the inner wall will be colder and any moisture in the home will settle on the wall at that place.
Ann P
Many thanks, G Y, but my security system won't let me read that!
Oh dear. Its an article on the website which is called 'Does cavity wall insulation case damp & condendsation' on the blog - its worth a read.
I'm with YouGen Limited
Ann P
In case I can't persuade my security to let me read it, what was the conclusion?
John S
Hi, I had a west facing wall that was very exposed and it suffered water penetration from heavy rain. Cured it with Thompsons water proofer. It's clear and simple to apply if you don't mind using a ladder
Roger G
There should be a guarantee attached to your cavity wall insulation work.
Do you have a guarantee document somewhere? You could contact the installers for advice.
Ann P
Great idea, John.  Once the cause has been sorted that's what we'll do.  Oddly enough, this wall is NE facing, but the principle still applies.  Thanks.

Thank you, too, Roger.  Do you know, neither of us remembers any documentation being offered at the end of the process.  There's nothing in our file, either.  It was done under a Council scheme, so I must ask about it.   Unusual for me to miss the paperwork!

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