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Question category:

Chimney & Fireplace

Fire cement vs heat-resistant silicone

Anonymous user 14 September 2023 - 1.01 PM

https://ibb.co/RPchf2q https://ibb.co/Yynndj1 Hi, I have a gap between the register/closure plate and the flue pipe (please see pics shared above). I'm worried that this is a source of heat loss from the fireplace and flat. Air and debris seem to be coming in. The stove is a wood-burning one and Snug 5 Eco. Can anyone confirm if fire cement or heat-resistant silicone is best for sealing this flue pipe and register plate gap? I'm planning to use VITCAS heat-resistant sealant or VITCAS fire cement. Would like to know which one is better. Thank you. Regards, D

6 answers from MyBuilder tradespeople

Best answer
C & S Chimney Services
Rating: 5 out of 5558 reviews
Blackburn

Cement is prone to cracking and falling off when the pipe expands with heat. I'd use the sealant, it tends to have more give.

Answered

14 September 2023

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Anonymous user

The issues are that silicones can bubble/move / melt etc especially if using standard high temp as the heat produced from the flue is over the max temp rating of most “high temp sealant” and fire cements can crack and fall out when it’s just stuffed into a gap which has so much movement under intense heat. The best solution would be to fit rope into the gap that’s fitted snug and then use a decorative rose (metal collar) that will cover the gap and makes it look seamless Just banging sealant and or cement in there may very well do the job for now but it probably won’t last long.

Answered

14 September 2023

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nick rowsell stonecraft
Rating: 5 out of 55521 reviews
Hexham

Fire cement, no question. It works for some considerable time. It’s pricey, but it works and is easier to apply than silicone. Also fireplaces, of any description, find cavities abhorrent.

Answered

14 September 2023

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R J RIDLEY BUILDERS
Rating: 5 out of 5552 reviews
Brampton

Fire rope is normally stuck around the register plate using heat proof mastic to prevent debris from falling out of the chimney.

Answered

14 September 2023

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Dr flue log burner and chimney specialist
Rating: 5 out of 55530 reviews
Hinckley

I go for higher temp silicon as it never cracks and seals the gap properly. I’ve never had an issue with it after 10 years.

Answered

14 September 2023

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Toasty Stoves
Rating: 4.9 out of 54.9531 reviews
Bristol

You might be better use of rope. Same rope that used in the door to seal. Cement will fail. As the metal moves in the heat. Silicone messy if gap more than 4 mm.

Answered

16 September 2023

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