MegaSack DRAW - This year's winner is user - rgwb
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Just been given a Jotul F100 by my sister which I'm thinking of installing in my office at home. As there is no chimney I'll be using twin wall (about 2m came with the stove plus 2m of single wall) - the question is whether to put it through the roof or out through the wall then up?
The office itself is a converted single storey double garage with solid 9" walls that have been lined with thermal plasterboard. There is no ceiling, just plasterboard beneath the Kingspan insulated roof which is tiled. Total flue height will probably be about 4m max.
I'm generally not keen on putting things through roofs unless you really have to, so at the moment I'm probably leaning towards going up in single wall, then changing to twin wall before a 45 deg bend, through the outside wall, then another 45 deg before going up to the required height.
Is there any particular reason why going straight up through the roof is better than the above?
It will probably be cheaper to go straight up and out (fewer expensive bits), and IMO I prefer to have flue inside - especially as you can have single skin to within 2x diameters of the ceiling acting as a radiator.
And how good are you cutting a 45 degree elliptical hole in your wall? 😉
Modern high temp silicone flashings, properly fitted, should be fine.
go up, nice hot flue inside the office, much more efficient. 🙂
Sorry, should have said that I would go up as high as possible in single wall before changing to twin wall.
Given that I've paid nothing for this (it does need a good clean/respray and a new glass), I don't really mind spending a bit on extra bits of twin wall if needed.
And how good are you cutting a 45 degree elliptical hole in your wall?
This could be an issue!
Sorry, should have said that I would go up as high as possible in single wall before changing to twin wall.
AFAIK the flue isn't allowed to have any joints other than at the exit of the fire and the top of the flue i.e it has to be one continuous flue from the fire.
Minimum height of a CHIMNEY system 4.5m
Maximum height of single wall flue is 1.8m.
Sorry Stoner......
Maximum height of single wall flue is 1.8m.
Ah, but I had assumed that since it was a single storey garage and the flue would start at the stove, and finish within 2 diameters of the roof, then it would be less than the 1.8m limit anyway.
Is 4.5m a statutory minimum or a practical one for draw? I thought the latter rather than the former.
highclimber - going from single to twin is still one flue.
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We have exactly the same arrangement for our Aga.
Make friends with your local chimney specialist and get him to do the installation. He will fit a sweeping port above the stove and he will certainly prefer a vertical flue for access and ease of fitting.
Here in Lancs I strongly recommend Ian at Acorn Chimneys in Burnley and strongly not the stove company in Ramsbottom whose labourer has some behavioural problems.
4.5m is minimum for building regulations and as you know for solid fuel you use either building regs or manufacturers instructions whichever is the stricter.
ah. just re-read s2.8, Part J.
For a building regulation it's written a bit more woolly than normal.
anyway, BS EN 13384 1:2005, gives you a get-out if a shorter flue tests OK for draw, No?
I'm totally confused now and I do this for a living 🙂
At a Dunsley stand at a trade show they had a stove burning away nicely outside in a gazebo thingy with a short chimney off the top.
"How come you recommend a min 4.5M chimney yet that stove is working perfect with <2M chimney?"
"Dunno, we put that in the recommendations because everyone else does." 😆
I'd always keep it inside where possible. Get all the heat out of it whether single or twinwall. Don't discount the cost of bends for twinwall either. The stuff I use costs £85 per bend.
SS chimney systems where lots of it is outside can be prone to reversing when cold aswell. Not a big deal this though but worth being aware of.
OK cheers guys. I think I may be near the 4.5m height if I go straight up simply due to the height of the roof. I shall give it more consideration and there's no rush.