How Far Above Roof Should Chimney Extend

This specification makes sure steep roof slopes are cleared.

How far above roof should chimney extend.

There must be at least 5 inches of clearance between the top of your tallest flue and the lid or roof of the chimney cap. The chimney must extend at least 3 above the highest point where it passes through a roof. Most wood stove and factory built fireplace manufacturers and local building codes will require that the chimney must extend at least 2 feet above any portion of any structure within 10 feet measured horizontally and must extend at least 3 feet above the highest point of its roof penetration. Continue reading below our video of the day.

The 10 foot rule explains the clearance you need. Most building codes require the chimney extend two feet higher than anything within ten feet horizontally. The flue should extend at least 3 feet above the roof. The chimney flue is the open shaft that runs from the firebox up through the chimney creating the passage for the fire smoke.

If the pipe is farther than 10 feet from the roof peak it must be 2. Vertical blue line along the left side of the chimney in our photo. The top of the chimney should be at least 3 ft 0 92 m above the roof surface. For gas vents or a type l vent this distance above the roof surface must be at least 2 ft 0 61m.

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. Specifications aren t there to merely cause you problems. And at least 2 higher than any portion of a building within 10. They intend to make sure that the chimney draws properly and that a fire hazard does not occur.

Select a chimney cap with a screen height 5 inches above your tallest flue at least 5 inches taller than the blue dotted line which metal is best for a top mount or multi flue chimney cap.