sealing around flue

[yamahamark]

Hi guys

Eon recently serviced system boiler located in converted garage now a room.
Flue got damaged during renovation but replaced by gas safe engineer, however the whole around it wasnt sealed so you can feel a draft from the wall cavity.

I need to seal the whole around the flue pipe, so can i use expanding foam or does it have to be mortar?

Thanks

 

[Destroyer2813]

Just use sand a d cement its what I always use

 

[yamahamark]

Yeah was just thinking foam quicker, easier and less mess.

Looks like i'll do what you suggested although its a bit awkward getting in with a trowel.

Thanks for your reply

 

[novicegas]

if you do use exp foam get the pink fire rated stuff.

 

[Whyme]

Carefull using too much foam cos it will spew everywhere when it expands.

 

[yamahamark]

Can i take it theres no issue or gas reg restricting use of foam as dont want eon moaning at next service.

I have used this stuff before on the odd occasion so understand not to squirt too much out!

 

[Guest123]

Should have a fire guard plate and sealed with intumescent fire cement.

 

[kozak1968]

Vaillant say mastic is acceptable to seal around the flue.

 

[villa_tom]

I wouldn't use expanding foam. I once saw a flue sealed with expanding foam and the foam warped and disturbed the flue joint. Admittidly the joint was screwed but still it wasn't a pretty site.

 

[AWheating]

any suitable seal that meets the fire rating of the wall and the manufacturers instructions should be fine. Sand a cement is the best option really, easy to mess with in the future also when you have a new boiler.