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Expanding Foam in Cavity Wall Mistake

Postby damyan24 » Mon Nov 09, 2020 5:52 pm

I am a landlord and my tenants experienced issues with damp on the inside of a bay window and it didn't seem like there was an issue with condensation or ventilation (as is usually the case). I noticed a crack where the bay window render meets the brickwork on the outside of the house and thought it may be causing the issue.

I thought I would fill the gap with an all-weather sealant in case this was the cause of the damp. The gap at the top (just above where the arrow is pointing) was fairly big (around 0.5-1cm) so I thought I would use some expanding foam first. Now I didn't realise that the gap was essentially leading straight to the wall cavity so all of the foam just fell down (750ml can). I only then realised it may have actually been a big (and very silly) mistake which could potentially lead to more issues.

I wanted to know if this is something I should worry about and whether there is anything I should do now before I experience any issues with that?
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Simply Build It

Postby stoneyboy » Wed Nov 11, 2020 9:24 pm

Hi damyan24
The globs of foam in the cavity will not be absorbent so there should be no risk of bridging the cavity, just don’t do it again!
Regards S
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