Anon the chimney outlet needs to not only be proper height above the roof surface but proper distance from any opening that could take flue exhaust.
Minimu chimney height above flat roof.
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.
For the next example you have a shorter chimney height.
Chimney heights and termination.
Per the 10 and 2 rule once you are at the level of the peak you only need to be 2 feet above it.
If your peak to penetration distance is 7 feet you would have a rise of 28 inches.
The distance between the cowl of the flue and the adjacent roof wall structure should be higher than 2 3 mtr.
On a flat roof may not be tall enough.
Positing a chimney on the home relative to the rest of the home may cause it to draw better.
If the chimney or flue exits the roof within 600mm horizontally of the ridge then the flue or chimney should be a minimum of 600mm above the ridge.
For the case you describe there are other distances like from windows and depending on the total chimney height even meeting the above roof minimum distance 3 ft.
The flue or chimney outlet must be above and outside of the shaded area.
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.
Chimney height regulations chimneys need to be high enough to ensure that smoke is directed away from where it might be harmful to your neighbours.
This will generally cause you fewer problems as a homeowner.
The 10 foot rule explains the clearance you need.
When a chimney is not adequately supported by ties or securely restrained in any way its height h when measured from the highest point of intersection with the roof surface gutter and so on should not exceed 4 5w provided the density of the masonry is greater than 1500 kg m 3 that is.
Brickwork heavyweight concrete block and so on where.
Diagram 2 shows the area on a traditionally constructed non flammable material roof where the flue must not terminate.
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.
So 28 inches plus 24 inches is a chimney height of only 52 inches.
The minimum chimney heights above roof are in the article above.
How far from a window must the chimney cowl be in the u k.
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.
If the pipe is farther than 10 feet from the roof.