Fill gap around gas fire flue.

We have a coal-effect gas fire with a flue that goes straight out through the wall. Unfortunately, there is a considerable draught coming into the room from behind the fire, which rather defeats the purpose of having it. Presumably, the hole in the breeze-block inner wall is much too large. It doesn't seem possible to dismantle the fire from the inside, because the flue is screwed onto the main chamber, and then the flue is cemented in place from the outside. I would like to avoid having to knock a few bricks out from the outside (which seems to me the only way to get access to the gap), and I was wondering if there is some kind of filler that would suit this application. I see there is a product called firefoam, but I don't know if it's meant to be used in a situation where it will get hot for repeated periods over the years. Does anyone think this would be suitable, or is there anything else I could use?
Thanks.
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On 20/12/2011 11:54, Sgt. Pinback wrote:

Hey Pinback, I thought the Bomb got you!
You need to think _very_ carefully about this. Not being suited up in your lounge it needs to be full of breathing air, and the fire likes that as much, if not more than, you do. If you block all the holes it might generate carbon monoxide, which even the least able spacer will know is Bad News.
x-posted to uk.d-i-y... they know more than I do.
Andy
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The flue that goes out of the wall - what sort is it? See http://www.valleyfiresandheating.co.uk/important-information-for-fires.html (for example) for the various options.
With luck, it's a balanced flue; in that case a) there is no need for ventilation in the room; b) you can fill round the flue with pretty much anything you like - the outer tube is responsible for bringing fresh air in, so it stays pretty cool.
If it's a chimney-type affair, I'd fit an appropriate ventilator, and fill round the flue with mortar (possibly reinforced with some fibre). I'd use lime mortar and goat hair, but I happen to have that in the shed; cement mortar and fibre glass would be fine too.
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wrote:

The flue that goes out of the wall - what sort is it? See http://www.valleyfiresandheating.co.uk/important-information-for-fires.html (for example) for the various options.
With luck, it's a balanced flue; in that case a) there is no need for ventilation in the room; b) you can fill round the flue with pretty much anything you like - the outer tube is responsible for bringing fresh air in, so it stays pretty cool.
If it's a chimney-type affair, I'd fit an appropriate ventilator, and fill round the flue with mortar (possibly reinforced with some fibre). I'd use lime mortar and goat hair, but I happen to have that in the shed; cement mortar and fibre glass would be fine too.
--------------
Yes, it's a balanced flue. The main problem is access - the back of the main chamber is only about an inch away from the wall, and it's quite large compared to the diameter of the flue, where the draught comes from. So, if I can't squirt some expanding stuff behind it, then I'm reduced to poking something in there with a stick, with no guarantee that it won't then just fall through the hole, and into the wall cavity. I can't get at it from the outside (without removing bricks), because it's all pointed up.
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similar. Suggest you obtain installation instructions for the fire which will tell you how to dismount either the flue or the fire to give access to the gap for filling.
There will be a spec plate on the fire which should give you the model name or number or at the very least the GCN (Gas Council Number) which is a unique gas appliance reference from which you can search for the manufacturer's details and installation instructions.
--
fred
it's a ba-na-na . . . .
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Only in body.

It's a balanced flue, so none of it reaches the room. Actually, it's pretty useless at heating the room at all - I'm sure most of the heat just goes out of the wall. I think it's just supposed to look pretty.

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