Height of stove flue?

[jcalow]

We have an existing gas stove with a balanced flue through the wall. We would like to upgrade this to a log burning stove with a piped flue. My question is how high would this piped flue approximately need to be? I have looked at building regs documentation, but found this confusing. Anyone have some experience or ideas on this. Does it need to go beyond the roof apex? I have attached a couple of pictures detailing the existing setup. New piped flue would exit pretty much where the balanced flue is now. Note that there is a skylite window on the end roof, don't know if this effects the flue height.

Many thanks in advance.

Untitled

• jcalow
• 7 Oct 2011
• 1

Untitled

• jcalow
• 7 Oct 2011
• 1

 

[RedHerring2]

Hopefully Richard C will be along soon with his links to the documentation.
IIRC, there is an excellent diagram in the regulations that indicate the minimal height above the roof for a flue in the posistion that you are thinking of. I know it's 600mm above ridge height when the flue is at the ridge but I can't remember the other heights off hand.

I also think that the minimum recommended height for a flue is something like 4 metres, anything less than that and the draw will be reduced and possibly problematic. This might be relevant to the type or make of stove installed.

Another consideration is that that is possibly the worst place to site a chimney 'cos of the flashing problems. It can be done, but there are better positions.

Edit: I've found one of Richard C's posts with the excellent links.
//www.diynot.com/forums/general-diy/open-fire-v-stove.292559/#2132435

This is a link to the appropriate page;
http://www.stovesonline.co.uk/flue-outlet-height.html

So I think we're talking 1 metre minimum height of flue above the top of the roof window. But it may need to be more.

 

[mointainwalker]

Recommendations are very general because the siting of the outlet will inevitably be more or less unique.


When I installed my stove, recommendations were :

1) Flue length min 4.20 m
2) Outlet min 40 cm above ridge line if more than 8 m away from higher points on surrounding buildings, otherwise 40 cm above that height.

1) My flue length is 3,50 m single-skinned and draws very well.
2) Outlet is 40 cm above ridge and is fine although it is only 6 m away from the wall of a higher building. Following the recommendations would have increased the height by another 2 m - very undesirable.

My house is located on a mainly open hillside so good wind-flow. If I were on the flat, surrounded by houses , who knows ?

I believe you need to look around at local houses with chimneys and ask their experience, as well as talking to a local fire-shop or sweep. Don't forget thought, that for something like this you will be subject to micro-conditions i.e. that big tree breaking the wind-flow, adjacent houses channeling the wind etc.

Looking at your pics, it really looks as if significant disruption to clean air is likely and so a longer flue would be advisable. But how long ........... ?