stove distance to combustibles

1 Oct 2012
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United Kingdom
Hi Diynotters

Before I get the stove installer back to fix it, I wanted to check with you folks...

Here's my stove install -

The chimney breast is metal studwork, faced in cement board. When the installer fitted the stove, the installer was aware that we wanted to hang a reclaimed wooden beam on those two brackets you see either side of the opening, with its bottom edge level with the opening.

Currently the distance from the outside of the flue to the front face of the chimney breast, where the wooden beam would be attached, is 12cm. It is 15cm single wall flue (it converts to twinwall higher up before going through the ceiling). Building regs distance, even with the cement board shielding, is 1.5x, so 22.5cm, I think? And the bottom of the beam that is not shielded needs to be 3x from the flue, which would seem to be not achievable at all...

Is the solution to get a building regs compliant distance to the beam to re-do the flue with twin wall, so the allowable distance to combustibles is 50-70mm depending on the flue type? Any other ideas?


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Twin wall would do it; alternatively move the beam further up.

A lot of the beams you see in pictures of installations are actually made from composite materials
What do the manufacturers instructions say? I have found wood burners which use a horizontal plastic flue, OK rather special, but the main problem with any fire using unrefined fuel be it wood, or coal, is keeping the temperature of flue gases low enough not to waste heat and high enough not to have particular emissions and there are many ways to get this, including water cooling, and water injection.

Only the manufacturer can really tell you how to fit their unit. How air needs to be supplied and flue gases removed.
Thanks for the replies - the stove manufacturer just talks about a standard 155mm flue, top or rear mounted.

Moving the wooden beam up unfortunately won't help, as it's single wall flue almost up to the ceiling inside the chimney breast (then it then changes to twinwall to go through the first floor joists).

I've got the installer coming back, he was aware when he installed it we had a (real) wood beam to put on the front, so I think he's going to have to change the flue...
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Study Part J. The distance is reduced if you can put a heat shield with air gap between the flue and the combustibles. Maybe you could move the beam up and create a heat shield within the dummy chimney breast

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