They intend to make sure that the chimney draws properly and that a fire hazard does not occur.
How high chimney above roof line uk.
This means that below 38 degree roof pitches that the height of the flue outlet should be at least 1800mm above the roof when not close to the ridge and above 38 degree roof pitches the flue outlet height should be 2300mm horizontally back to the roof flue height figures are given in the table above where the flue is not close to the ridge.
Keep in mind that there is generally a minimum chimney height requirement for the overall system usually 15 feet which sometimes includes connector pipe that can affect the finished height of your chimney system.
Specifications aren t there to merely cause you problems.
The chimney must extend at least 3 above the highest point where it passes through a roof.
Homes built on varying terrain have their own set of chimney and flue regulations.
These rules helps ensure draft is not spoiled by wind induced turbulence.
Imagine an imaginary horizontal line extending 2 3m in all directions.
We also have the 2 3m rule.
If the top of the chimney is within 600mm 60cm of the ridge it should finish 60cm higher than 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.
If the pipe is farther than 10 feet from the roof peak it must be 2.
Degrees the height of flue or chimney stack will need to be at least 1800mm above the roof when not close to the ridge.
Chimneys shall extend at least 2 feet 610 mm higher than any portion of a building within 10 feet 3048 mm but shall not be less than 3 feet 914 mm above the point where the chimney passes through the roof.
The 10 foot rule explains the clearance you need.
Flues need to be 600mm higher than the highest part of the roof within 3 metres.
Other factors can influence the necessary height of the chimney such as house stack effect and high altitude.
And at least 2 higher than any portion of a building within 10.
Both above the flat roof and 2 feet above the point at which a horizontal line from the chimney would touch the highest portion of the nearest roof.
The top of a chimney pipe must extend at least 2 feet above the peak of the roof if the pipe is within 10 feet of the peak.
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.