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Chimney Lining & Vermiculite
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greyteam1959
Posts: 4,710 Forumite


I am going to replace my 25 year old multi fuel stove with a new one.
The house is now about 100 years old & I will be lining the chimney with a flexible 904 liner.
I have been told that I should have the chimney 'back filled' with vermiculite after the liner has been fitted. This will stop the new flue moving about when being swept & provide insulation.
20 bags at £20 per bag.........
Is this an expensive add on or a reasonable thing to do ???
Oh & what happens if you need to replace the liner at some stage if the chimney is loose filled with vermiculite ??
The house is now about 100 years old & I will be lining the chimney with a flexible 904 liner.
I have been told that I should have the chimney 'back filled' with vermiculite after the liner has been fitted. This will stop the new flue moving about when being swept & provide insulation.
20 bags at £20 per bag.........
Is this an expensive add on or a reasonable thing to do ???
Oh & what happens if you need to replace the liner at some stage if the chimney is loose filled with vermiculite ??
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Comments
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I am going to replace my 25 year old multi fuel stove with a new one.
The house is now about 100 years old & I will be lining the chimney with a flexible 904 liner.
I have been told that I should have the chimney 'back filled' with vermiculite after the liner has been fitted. This will stop the new flue moving about when being swept & provide insulation.
20 bags at £20 per bag.........
Is this an expensive add on or a reasonable thing to do ???
Oh & what happens if you need to replace the liner at some stage if the chimney is loose filled with vermiculite ??
Sounds like a good plan to me but not sure if expensive.0 -
Have they explained what you will do, or what it will cost, should the liner crack, and the broken bit is inaccesible owing to having back filled it with vermiculite?0
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Best person to ask would be Hethmar he's a fitter.You may click thanks if you found my advice useful0
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The man who installed my stove (HETAs registered, for what that's worth) doesn't recommend it - implying that it's 'a nice earner' for installers but can cause problems with damp. I didn't press him on exactly what these problems were but as he is the main local installer in an area with a lot of stoves. I took his advice.0
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I have done some more research on this.
I have a feeling that using vermiculite or any other back fill product may not be such a good idea as it sounds.
If the liner has ever to be replaced 20 bags of sooty vermiculite is going to cause a right mess when it has to be removed !!
Dampness also seems like it might be an issue with the stuff as well.
I was a little suspicious that it sounded like a 'nice little earner' when it was suggested by the place that was selling the new stove.0 -
My sweep says insulating a liner is not needed on an internal stack, only if the stack is on an outside wall of the house.
This made sense to me as a stack on an outside wall will be colder than a stack in the middle of the house .
Willie.0 -
Sorry, only just seen this. We always recommend using insulation - usually vermiculite if its an average flueway or rock wool wraps in a large flueway. It is also recommended by the manufacturers of the liners and a must do in thatched properties.
It provides insulation and support for the liner. A warm flue is less likely to have any resin problems or transfer heat to resin already in the brickwork. We also put a metre long insert in at the top of the flueway as additional protection for the liner in its most vulnerable place.
Its not a nice little earner actually - its a hard old slog up and down ladders and across roofs carrying the bags of material - hence why many an installer will not recommend or mention it. Much easier to sling down the liner, hang it by a diy pot hanger (without even removing the pot) and be on your way.
But, you pays your money and takes your choice. (20 bags is a huge amount for a standard flueway - if its a large one, then ask for wraps to go round the liner)0
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