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By lathehunter
#1273490
I have converted my concrete block with asbestos roof construction garage to a workshop with patio doors and now want to fit a small log burner.
My question is can I run the flue 1.8mtr up from the stove and use a 90 degree bend to go through the wall and have the pipe end just proud of the outside wall? The reason being I don't want to cut the roofing material.
Any advise would be appreciated
By sunnybob
#1273496
90 degree bends tend to cause flue problems. avoid them if you can by fitting 135 degree and going through the wall at an angle. More work, but a much better efficiency of heat.
By phil.p
#1273546
90 degree bends are a no no to stove fitters - use two 135s. If you fit a stove ensure your garage is quite draught proof and well insulated or you will guarantee condensation problems.
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By Doug B
#1273573
phil.p wrote:If you fit a stove ensure your garage is quite draught proof


Possibly the most dangerous “advice” I’ve seen on a forum, people die from carbon monoxide poisoning cause by lack of air supply to stoves, what ever you do decide to do DON’T seal up your garage if you intend to fit & use a log burner .
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By MikeG.
#1273577
Doug B wrote:
phil.p wrote:If you fit a stove ensure your garage is quite draught proof


Possibly the most dangerous “advice” I’ve seen on a forum, people die from carbon monoxide poisoning cause by lack of air supply to stoves, what ever you do decide to do DON’T seal up your garage if you intend to fit & use a log burner .


The ideal situation is a dedicated air vent situated adjacent to the woodburner, and a carbon monoxide alarm. Even better, it is possible with many woodburners to pipe the air supply direct into the bottom of the stove. This removes draughts from the room and ensures that the fire will at all times have the air it needs to work.

ETA....

Just to be a bit pedantic, it isn't the lack of air supply to the stove which causes a build up of carbon monoxide, it is a leakage of the products of combustion into the room exacerbated by a lack of a fresh air supply to the room occupants. It is perfectly possible to have a room sealed air supply to the fire (ie the ideal situation), and yet still have carbon monoxide levels rising in the room.
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By Doug B
#1273579
MikeG. wrote:
Just to be a bit pedantic, it isn't the lack of air supply to the stove which causes a build up of carbon monoxide, it is a leakage of the products of combustion into the room exacerbated by a lack of a fresh air supply to the room occupants. .


To be fair Mike the two are inextricably linked as your sentence also suggests, the bottom line is a wood burner needs ventilation & by its nature an open vent where ever it is placed will cause a draught, I have no idea who the OP is but clearly by asking this question he is showing his lack of knowledge so folks should be careful what they say in reply.
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By Marineboy
#1273580
The log burner in my lounge does not have a room sealed air supply, just the ‘normal’ ventilation which comes in via the doors etc in my leaky Victorian house. However, I have never noticed any draughts, I think the combustion process is so efficient that the demand for air is well controlled.
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By doctor Bob
#1273583
I may well be talking out of my ass, but if it's not fitted by a hetas installer (I don't think you have mentioned whos installing) I supect any insurance etc would be null and void.
By Woody2Shoes
#1273587
I think it's worth mentioning that a significant proportion of the heat that you get by burning wood in a logburner actually comes from burning CO - which is a calorific gas in its own right, and used to be a significant component of "town gas" derived from coal. In other words, a correctly functioning stove will create and burn CO - the problem comes, as Mike and others indicate, if that gets drawn out into your breathing space.

I would check that a 6ft flue is long enough (it probably isn't - the manufacturer's data sheet should specify) to provide a satisfactory "draw" - which is necessary for efficient and safe combustion (as it helps to prevent a downdraft which would put CO etc into the room). The flue terminal also needs to be positioned correctly in relation to the ridge of the roof (looking at Building Regs would help here - Parts J and L from memory). Building Regs are also useful as they give guidance on minimum hearth sizes and other construction rules - the other obvious hazard being fire!

There would be a lot to be said for getting a HETAS installer to supervise/sign-off an installation such as this. I believe that HETAS regs can be found online as can Building Regs.

I have CO detectors and fire alarms wherever I have a solid fuel stove.

Cheers, W2S
By chaoticbob
#1273966
lathehunter wrote:I have converted my concrete block with asbestos roof construction garage to a workshop with patio doors and now want to fit a small log burner.
My question is can I run the flue 1.8mtr up from the stove and use a 90 degree bend to go through the wall and have the pipe end just proud of the outside wall? The reason being I don't want to cut the roofing material.
Any advise would be appreciated


If you are thinking of an 1.8m rise inside the garage and the outlet protruding horizontally outside the wall without any external vertical flue, the answer is an unequivocal 'no'. Apart from safety considerations, you simply won't get enough updraught to run the stove properly. You will need an insulated vertical external flue at least 3m long.
As W2S said, HETAS guidelines are available online - eg here.
Well worth a read.
You don't need to have a HETAS engineer do the installation, but if you want to comply with building regs and insurance requirements you need to get one in to sign it off - they fix a riveted plate on the work certifying conformity.
I suppose most of us with home workshops take risks from time to time, but in my case I sort of creep up on danger - whoops, that was a bit scary, not going there again. You might not get that option with carbon monoxide poisoning or fire though.
Obviously I have been down this route myself - I ended up taking professional advice.
Robin