Gap around boiler flue

[Michael Wojcik]

Hi

After a bit of advice, need the gap around my boiler flue filled with something to stop the wind getting In see pic and was thinking of using fire proof expanding foam.

Would this be ok?

 

[simond]

Yes it would, but the $6M question is, who installed it like that in the first place?

 

[Michael Wojcik]

No idea like this b4 we moved in

 

[steve32]

Sand and cement would be best

 

[gigz]

Sand and cement outside, decorators caulk inside.

 

[BigSnoopy01]

Has the boiler been moved? as it looks like it has some patching material on it already. The outside needs patching ASAP as any decent engineer will turn it off in this situation. Outside use sand and cement, inside I'd remove the old stuff, fill with sand and cement a few mm below finished surface and the fill over that to a smooth finish.

 

[simond]

Some manufacturers will allow you to use just the external rubber ring as the seal (eg: Worcester) but any diligent installer would use cement mortar outside and render inside. But fire rated foam would suffice. For all we know the flue is 5 floors up.

Nb: this engineer would use fire rated foam if it wasnt a cavity wall rather than turn it off - or sand cement.

 

[Agile]

Gas Safe inspectors don't like seeing just the gaskets used.

Also not cementing outside risks water getting into the brickwork. G-S consider the installation as classed as At Risk with an unsealed flue which means it should be turned off.

I prefer to use plaster inside as that makes removing easier. Its a real pain when the installer uses cement on the inside.

My view is that a gasket inside is totally adequate when cemented outside. Most G-S inspectors don't like them though.

Tony

 

[shambolic]

Don't use foam as it makes it nearly impossible to remove flue in future if boiler needs it off for repair.

 

[Agile]

I have never wanted to use foam on a flue.

But for other applications, I have never managed to reuse a foam can again so presumably those who do must dedicate a can to an installation or is there some way to use them again?

 

[steve32]

I have never wanted to use foam on a flue.

But for other applications, I have never managed to reuse a foam can again so presumably those who do must dedicate a can to an installation or is there some way to use them again?

If you must use foam you need a foam gun and cleaner and the correct can of foam.

http://www.screwfix.com/c/sealants-adhesives/guns-cleaners/cat850112


http://www.screwfix.com/p/soudal-flexible-expanding-foam-gun-grade-750ml/96928

 

[TCCHeating]

If you must use foam you need a foam gun and cleaner and the correct can of foam.

http://www.screwfix.com/c/sealants-adhesives/guns-cleaners/cat850112


http://www.screwfix.com/p/soudal-flexible-expanding-foam-gun-grade-750ml/96928

Also. To complete the 'look' while applying the foam. You must invest in a pair of these

And these

 

[BigSnoopy01]

WB may allow the rubber to be the seal but they also ask for the gap to be filled from the inside which suggest they only expect this to be done on flats above 3 story (for access reasons) imo.

 

[DrWho]

Sorry for replying to an old thread.

I have gaps on my flue at wall above the boiler, which is the best method to fill these gaps apart from foam as the flue as per image is attached to plasterboard wall.

 

[denso13]

which is the best method to fill these gaps

You've asked this before. Sand/cement or plaster as it is plasterboard.