Flues through timber kits.

[mike-c]

Can some nice person please point me in the direction of the regulations in regard to fitting a horizontal flue through a timber kit with a brick outer skin. Also are there differing rules for Scotland over England?
thanks in advance.

 

[Barry98]

Without looking I think and stress the word think it just has to be suitably sealed so poc cannot re enter

 

[Barry98]

The seal should be a non combustible material also I think , Again stress the word think a gap of 50mm should be left to allow for swelling of the wood

 

[johnnyplumb]

you need a non combustible sleeve as bod says with a 25mm gap all round the flue, so if flue is 4 inch , you need a 6 inch sleeve, sleeve has to be continous through the wall, dont think the regs are any different in scotland than england.

 

[Barry98]

Is it 25 sorry , I did say I'd have to look

 

[johnnyplumb]

it's overkill, if you ask me, especially with condensing boilers,
it's impossible to seal when doing on a top flat with no access to outside.

 

[tamz]

There are a couple of recommended ways of doing it.
Either using a sleeve ( a cutting of 6" supersleve will do) which is fitted across the kit only. It shouldn't extend into the cavity by more than 10mm.
or by cutting out a section of the plasterboard and framing a square which is then lined with masterboard or similar.
You should also really put a drip collar around the flue in the centre of the cavity (a piece of wire wrapped around the flue and twisted at the bottom or a bead of silicon) to prevent moisture travelling along the flue to the kit. I've never seen that done tho.

 

[AWheating]

On the timber framed jobs ive worked on we have done roughly what tamz has discribed.

check out page 26 onwards
http://www.igem.org.uk/media/80398/UP-7-Edition-2 _Comm-1722.pdf

 

[mike-c]

On the timber framed jobs ive worked on we have done roughly what tamz has discribed.

check out page 26 onwards
http://www.igem.org.uk/media/80398/UP-7-Edition-2%20_Comm-1722.pdf

Thanks for that AW.
i had already found that elsewhere but I was hoping against hope that there might have been a simpler method.
i have been left to cover a job whilst the boss is on holiday and the builders and site agent have decided not to take the advice that he gave them before he left and are now putting the squeeze on me to get 16 flues fitted in a block of flats before the rendering is done on Wednesday.
I also have my own work to do in that timeframe for another job as the tilers are booked there for Thursday and there are 2baths and a shower tray to be fitted.
Happy days (where did I put that noose again).

 

[johnnyplumb]

cheers tamz & aw, must admit i usually sleeve the whole depth of the wall in a kit house, see alot done like that,
i've just read the above link, looks like you can get away with a 10mm gap between flue and sleeve if a condensing boiler, probably makes more sense.