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    Hello all,

    Am planning to have a small office-cum-bloke's bolthole in a wooden shed/log cabin type thing, situated at the bottom of the garden. Nothing massive, think fancy garden shed. It'll be insulated, of course. Regarding lighting, one option is connecting it to the electricity, the other is an oil lamp or two. For heating, electricity is the obvious option, but I like the idea of a small output woodburner (e.g. Aarrow Acorn, Stovax Brunel etc.).

    Can anybody here advise on the legal/practicality issues of installing a woodburner in such a building? Obviously, the burner would be standing on a fire-proof hearth, but other issues? E.g....how high would the flue/chimney need to be? What are the issues with having a hot flue/chimney going up through a wooden roof?

    We're in a rural area, quite high up, can get windy. Neighbours both use woodburners.

    If anybody can advise or share experiences on this, I'd be happy to hear your thoughts.
    • CommentAuthorjoe.e
    • CommentTimeJul 5th 2008 edited
    I have precisely what you describe - an office / cabin, which I've fitted a woodburner in. The building was a leaky static caravan when we bought the house, with the tow hitch too rusted to pull the thing out, and the garden grown up since it was put in there; I clad around it with 100mm stud/sheepswool insulation, put a steel roof over the top with lots more sheepswool underneath, cut the windows out and fitted new wooden frames with DG, waney-edged larch cladding outside, new floor... Now the old caravan is a kind of lining to the new building.
    Anyway, the place is so small it seemed to me that it wasn't too critical how much heat I got from the stove, so I put a super-cheap pot-bellied stove from Machine Mart in. If I light it in midwinter, I have to open the windows after ten minutes. I didn't pay much attention to the legalities, I'm afraid; I did pay some attention to the safety aspect by fitting an air vent behind the stove; running the flue through the ceiling through a section of bigger steel pipe, with the gap packed with rockwool; having the top of the flue 400mm clear of the highest point of the roof for clear updraft; stove on thick ceramic tiles.
    It's all very satisfactory, except that when the burner goes out it all gets cold quite fast due to not much thermal mass.
    Thanks Joe. Since posting, we've pretty much finalised the cabin type...44mm softwoord t&g walls, 20mm roof and floor. All will be insulated to increase this thickness. Have now worked out stove output, so we just need a bit more advice on any regs re. flue height etc., plus the slightly worrying bit about cutting a hole in the roof of an expensive log cabin...
    If you, or anyone else on the forum, has, or gets, the smallest Machine Mart pot-belly, I have 2 brand-new grates for it. They break in the heat, but equally the stoves die in a damp (boat) environment, so the stove did not last long enough to need the grates. Free to good home. You pay postage.

    • CommentAuthorCWatters
    • CommentTimeJul 8th 2008
    Ideally flue height should be at least 600mm above the ridge. See "A" on Diagram 17 page 26 for examples


    The hole will need to be covered with a "Flue Flashing kit". Various types are available depending on the roof covering (tiles, felt, plastic etc). You need one designed for a hot flue pipe not a twin wall gas boiler flue. Examples...

    • CommentAuthorcontadino
    • CommentTimeJul 8th 2008
    It might be worth reading the sections on "Stoves in funny places" at http://www.stovesonline.co.uk/stove_help_and_advice.html

    Things like boats, yurts, and buildings with sedum roofs are covered.
    • CommentAuthorWindy
    • CommentTimeJul 18th 2008
    Some of the cheaper pot bellies have been known to crack their castings while in normal use! Beware at your peril.

    You will need to put the burner on a stone plinth, and surround it with fire board or at a pinch aluminium sheet. Whatever you use, its important to have a 1/2" air gap behind the board/ally, with air able to flow from top to bottom, for cooling.

    Also its important to ensure that any fixings (screws etc) are to the dge of the board, as they can transmit heat from the burner through to the wood and start a fire.

    You can start off with single skin flue (DO NOT USE GALVANISED SINGLE SKIN), then carry on with an adapter to twinwall to pass through the roof. The roof can be sealed with the rubber flashing, and the flue terminated with a rain hat or storm cowl.

    Many people use single skin vitreous enamel flue all the way through the roof. This has proven to be safer than hanging your socks over the burner, but if building regs applied to caravans, would be very naughty indeed!

    Remember that if you are using single skin through the roof, you will have to use the high temperature (red) silicone flashing, which is safe to 240 degrees C.

    If you havent yet decided on which stove to go for, then have a look at: http://www.windysmithy.co.uk/html/woodburners.htm

    If you have any further concerns, let me know, Jon.
    • CommentAuthorMrKeating
    • CommentTimeAug 27th 2008
    Hi Jon,

    You say emphatically 'DO NOT USE GALVANISED SINGLE SKIN'! Can you tell me what the issues are with this?

    Many thanks
    • CommentAuthorWindy
    • CommentTimeNov 4th 2008
    The zinc coating burns off, which give off poisonous gases, then the paper thin steel is exposed to the corrosive flue gases.

    These will rot the steel in no time at all, allowing the fumes to come into the room, where you or your loved ones may be sleeping.

    Carbon monoxide kills, very unfortunately.
    • CommentAuthorjoe.e
    • CommentTimeNov 4th 2008 edited
    Out of interest, does anyone know of any fatalities caused by carbon monoxide leaking from woodburning stoves?
    Edited - just found this: http://www.carbonmonoxidekills.com/carbon_monoxide_deaths.htm - in 1987-1996, from 438 cases of carbon monoxide poisoning, one was caused by burning wood; the type of appliance is listed as 'unknown', so could be an open fire or woodburner, or conceivably some type of boiler. Interestingly, there were 13 deaths caused by burning non-wood solid fuel in open fireplaces.
    • CommentAuthorbevs
    • CommentTimeNov 11th 2008
    I am also building a similar building in my garden and will put in a wood burner but I want to take the flue through the wall and not roof, it is wooden construction do you think this will be ok.
    • CommentAuthorCWatters
    • CommentTimeNov 11th 2008
    Get it installed by a Hetas approved installer and it should be fine. Thatched cottages can have wood burning fires and stoves.
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