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House stuff - wood stove flue height question
Mr Whippy - 8/6/18 at 06:15 AM

Hi,

Not remotely car related but for a wood burning stove does the flue need to be level with the ridge or above it?

Cheers

jps - 8/6/18 at 06:28 AM

Can't remember the details but it depends how close it is to the ridge as to whether building regs says it has to be above or not. But I would say "think of your neighbours", ours put a stove in and filled our garden with smoke on a daily basis. Although their flue height was regs compliant there were all sorts of downdraughts thanks to prevailing winds and the roof shape..

We built an extension (and fitted a woodburner) and went for the tallest chimney we could...

Mr Whippy - 8/6/18 at 06:36 AM

almost all our neighbours have solid fuel fires as most are old style cottages, were lucky in that the prevailing winds 95% of the time are blowing away from the row of houses out to sea so affects no one and the flue will be on the sea facing side. But a good point.

Agriv8 - 8/6/18 at 06:47 AM

Whippy no idea on if it needs to be above ridge line buy the flue will need to be over a 'Certain' length I would have thought to create enough 'Draw' for the stove to work.

Regards Agriv8

hughpinder - 8/6/18 at 07:39 AM

Here you go:

https://www.flue-pipes.com/tips/height-on-roof

Regards
Hugh

Sam_68 - 8/6/18 at 08:01 AM

quote:
Originally posted by hughpinder
Here you go:

https://www.flue-pipes.com/tips/height-on-roof


The diagram that's based on is from Approved Document J to the Building Regulations.

See pages 31 & 32, on this link

Mr Whippy - 8/6/18 at 08:50 AM

well done, that's exactly what I needed

Thanks

Mr Whippy - 8/6/18 at 08:58 AM

seems reading through that I actually need a vastly lower flue than I first thought

HowardB - 8/6/18 at 09:09 AM

not sure on this particular case, but are some building regs different in Scotland,... ?

jps - 8/6/18 at 10:01 AM

quote:
Originally posted by Mr Whippy
seems reading through that I actually need a vastly lower flue than I first thought


I think this is the big point - "need - to conform with building regs" vs "need - to not have smoke flow problems in your specific setting" is not necessarily the same thing!!!

From memory I found it hard to get info about 'tuning optimum flue length' anywhere - but we have a considerably longer flue than the minimum regs requirement and have no problem with the amount of draw on the fire (although our flue is in a brick chimney stack so warms up and holds the heat well - don't know how it'd work with an external metal tube flue)...

David Jenkins - 8/6/18 at 11:03 AM

As an aside - our chimney-sweep loves the external flues with a double wall and insulation between. They rarely get tarred up and are a delight to clean (he says).

Mr Whippy - 8/6/18 at 11:03 AM

yeah, the company I'm buying it all off has been super helpful and has just supplied me all the info and parts list I needed

Turns out I need just 2.4m of flue sticking out the roof, bonus.

As for the flue type its the double walled stainless one which I have used before, it's amazing stuff and retains it's heat so well you can hold the outside with you bare hand yet it's glowing inside, if we have issues with lack of flow I can just order another length...