The grey area in the picture shows where the flue must not terminate on a roof with standard non flammable roof.
Flue height above roof.
If the pitch of the roof is 38 degrees or greater the termination point of the flue or chimney will need to be 2300mm horizontally from the roof line and roofing material.
The picture below may illustrate it better than my words.
Should your roof be thatched or made of any other combustible material then as you can imagine these distances must increase.
Felted roofs the flue must terminate a minimum of 1 8m above the combustible surface.
Flues need to be 600mm higher than the highest part of the roof within 3 metres.
If the flue is over 3 m from the roof apex the flue top must be 1 000 mm minimum above the roof and at least 3 m horizontally from.
The minimum height of the top of the flue varies depending on where it is on the roof.
The distance between the cowl of the flue and the adjacent roof wall structure should be higher than 2 3 mtr.
We can work out the height required when we design your system.
As illustrated below if your flue exits through the roof within section a then you are required to rise at least 1800mm vertically above the roof surface and at least 600mm above the ridge.
For buildings with combustible roofs e g.
Back to our example over a run of 10 feet the roof would rise 40 inches.
Additionally per our rule we need to add 2 feet or 24 inches giving us a total height of 64 inches.
Roof pitch rise run in inchesminimum height flat to 7 12 1 0 foot above the roof surface 7 12 to 8 12 1 5 feet above the roof surface 8 12 to 9 12 2 0 feet above the roof surface.
The minimum chimney height recommended for minimum performance of wood burning and multi fuel appliances is 4 5 m from the top of the appliance to the top of the chimney.
If unsure please give us a call.
So take the top number of your roof pitch and multiply it by 10 then add 24 note example 1.
Vent caps 12 and smaller may terminate a distance above the roof if 8 feet or more away from a vertical surface as follows.
The height of the chimney above the roof surface measured at the up slope side of the chimney from the roof surface to the chimney top should be at least three feet the green line in our photo.
Degrees the height of flue or chimney stack will need to be at least 1800mm above the roof when not close to the ridge.
Do i need extra room ventilation.
Flue outlet height unsafe areas diagram.
The flue termination is within 600mm horizontally of the ridge in which case the flue finish at least 600mm above the ridge.
Flues that are more than 3 metres away from the highest part of the roof need to be 1000mm above the flue penetration.
Homes built on varying terrain have their own set of chimney and flue regulations.
