Sealing up cold breezes

adamdamienlynch@gmai · 21 Nov 2025

I have a gas boiler, glow worm r25 and I have noticed a cold breeze coming from outside, this is definitely stronger on windy days and is present when the boiler is not it in use. My question is can is seal this up with hi temperature expanding form or is this a no, no. Pictures in thread

cross thread · 22 Nov 2025

Yes it looks like they didn’t seal when they put the safety pipe through,

ToolboxTalks · 22 Nov 2025

I wouldn’t seal that with expanding foam. Boilers need a clear path for ventilation, and blocking that gap could cause bigger safety problems.

adamdamienlynch@gmai · 22 Nov 2025

I was thinking that expanding form would not be a good idea when it come to services and inspections. I was considering making a plasterboard insert with some vent holes in it, instead of the gaping hole that is currently there. Thoughts?

danfre · 22 Nov 2025

Gap defently not needed for ventilation. If it was a old opened flue boiler it would have a proper vent cover not a gap

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sealing up cold breezes

adamdamienlynch@gmai

Attachments

cross thread

ToolboxTalks

adamdamienlynch@gmai

danfre

DIYnot Local

Similar threads