log burner flue

[reb78]

What's the best way to pass a rear (horizontal) exit 6" log burner flue through a cavity wall and out? Does it need a 45 degree bend then diagonally out through the wall and another 45 to put it upright to run up the outside wall? Best to use twin wall through the cavity? Can it be run horizontally through the wall and then connected to a 90 bend that goes straight up? The wall is probably about a foot from inside through the cavity to outside.

This is in a home workshop not the house.

 

[gaz1]

the best way is 45 degree to a tee then you can use another 2 45 degree bends as you have then used 4 45 degree bends in the chimney which is the limit

straight up is the prefered method but you can use the rear by using a tee then a 45 degree to outside then another tee

straight out through the rear is not the prefered way due to heat and wear and tear on the stove pipe
neither is out of the stove and into a 90 to outside then a tee piece

the tee piece is for clean outs of the flue and needs a cap at the bottom or a sealed collection box of ash if anything drops down the flue pipe or during clean outs of the flue when rodding it

 

[reb78]

I'd like to avoid straight up as it seems easier to take it through the wall to the outside than through the roof and tiles. Easier to seal anyway.

So, I am thinking 45 to get the angle, then diagonally out through the wall and then 45 to put it upright again and straight up to above the ridge height. Not sure i need a tee in there at all as these flexible drill rods I have will go straight up without a tee and seem to get more muck out than conventional rods and brush strangely.

Should it be twin walled as it goes through the wall and then switch to single? It will be too high for anyone to touch once outside so no risks there.

 

[gaz1]

nope 45 degree through the wall best not to use diagonal pieces ( but theres a but )

you need a tee for cleaning or a double tee if a long pipe to the outside

first is on top of the stove or other the next 2 are from the rear of the stove or other


open up connection to the chimney read up on diagonall pieces

Chimney & Flue Design - Wood & Solid Fuel - BFCMA (British Flue and Chimney Manufacturer's Association)

The BFCMA, the British Flue and Chimney Manufacturer's Association, is the UK's only Trade Association for factory-made chimney products.

www.bfcma.co.uk

 

[reb78]

nope 45 degree through the wall best not to use diagonal pieces ( but theres a but )

you need a tee for cleaning or a double tee if a long pipe to the outside

first is on top of the stove or other the next 2 are from the rear of the stove or other

View attachment 449332View attachment 449333View attachment 449334
open up connection to the chimney read up on diagonall pieces

Chimney & Flue Design - Wood & Solid Fuel - BFCMA (British Flue and Chimney Manufacturer's Association)

The BFCMA, the British Flue and Chimney Manufacturer's Association, is the UK's only Trade Association for factory-made chimney products.

www.bfcma.co.uk

I think we are agreeing. Your bottom pic is what i was thinking but didnt know if i really needed the external access at the bottom as can clean from inside really.

 

[Bobtail4x4]

you are only supposed to have a maximum of 2 45 degree bends, and no horizontal bits,

 

[gaz1]

your allowed 4 in the diagrams above 3 in total the other with a tee piece

horizontal bits preferably avoided but as shown there is a but

though i would rather not use horizontal even within the exception

 

[Kj1123]

I echo everything said above just to answer your question defo go through the wall with twin wall flue. Most important thing to do is cut back any insulation, plaster board slabs ect to the manufacturer of the flue pipes recommended distance to combustible materials usually 50/60mm but can vary also make sure this distance is maintained to the cavity in the wall with ether a sleeve or pack around the pipe with rockwool fireproof insulation. That is very important as if the cavity wall are ever pump down the road the bead cannot be blown up against the pipe and start to burn. Also go as high as possible with your flue usually u can go 1,1/2 meter after your last brackets at the gutter higher the flue better the draw ideal if u can get up past the ride into clear airflow but not always possible just go as high as u can u are supposed to be a minium of 2.4m from and velux windows or vents.

 

[reb78]

I echo everything said above just to answer your question defo go through the wall with twin wall flue. Most important thing to do is cut back any insulation, plaster board slabs ect to the manufacturer of the flue pipes recommended distance to combustible materials usually 50/60mm but can vary also make sure this distance is maintained to the cavity in the wall with ether a sleeve or pack around the pipe with rockwool fireproof insulation. That is very important as if the cavity wall are ever pump down the road the bead cannot be blown up against the pipe and start to burn. Also go as high as possible with your flue usually u can go 1,1/2 meter after your last brackets at the gutter higher the flue better the draw ideal if u can get up past the ride into clear airflow but not always possible just go as high as u can u are supposed to be a minium of 2.4m from and velux windows or vents.

Really helpful. Thanks. Think thats all i need to know now.

Eta - no chance of cavity bead insulation going in here, so thats not a worry in this instance - its a garage and I won't use cavity bead insulation anyway.

 

[gaz1]

with the rocket stove its different and also a lot lower down on the exit the flue also dosnt hit the tamps of a normal stove at the flue either

ive also used galvanised spiral duct pipe whilst the top layer of the galvanised diagonal piece has lost its galvanised material the rest of the duct has not