Sealing up flue on a multifuel stove - fire cement / silicone?

JustAnotherSaver

I hope it's called a flue. the picture will show what i'm on about anyway.

The chap who installed the fire said that with the heat & then the cooling, the cement that i'm pointing at in the photo will need toppin up / replacing.



I've read that fire cement should be used, but i've also read you can use some sort of fireproof silicone.

Is either/or ok for the job really or is it best to use one over the other for some reason?




While i'm at it about this fire thing ......

behind the fire is some fire board & the joint was filled, i imagine with some heat resistant silicone.
It must've either shrunk or not been filled too great because i can see the gap.
Any particular sealant in this case that you'd recommend as being good for the job? Sorry i didn't take a photo of that.

chappers

Would have thought either.
Was the installer HETAS registered. I'm not sure but I can't believe it's OK to use a product that will fail over time.

JustAnotherSaver

Yes he was.

So you're saying fire cement there should last the lifetime of the fire?

Not challenging what you're saying, just asking for clarification.

theonlywayisup

We replace fire cement every year or so. It does crack but it's easy to repair/replace.

Can you take a picture of the gap problem as I'm not sure what you mean?

Davesnave

Just confirming fire cement does crack and need replacing periodically; mine twice in 6 years.

JustAnotherSaver

I don't think it's cracked so bad. It was installed a month or so ago. I was just trying to gain knowledge for the future really but I can take a close up photo no problem. It'll just be tonight that's all.

Any takers on the board at the rear (the joints)?

dominoman

Small cracks, like crazing, you can ignore. You only have to worry if you think the crack is large enough to allow a leak into the room.

Ours was installed six months ago and we have several thin cracks, but they haven't opened up so we leave them alone

JustAnotherSaver

On that note it should be fine. I saw no smoke coming from the cracks.

But still ... If/when the day comes .....??

Davesnave

My fire had gaps around where the boiler pipes leave it. I plugged these with fire cement too and have had no problems since. This is the case even though I've now sawn off the pipes to just leave stubs, as I don't need or want the boiler facility.

The fire is a different beast altogether now; much better performing and nowhere near as sooty.