How high above the roof does my chimney have to be?
The following information is for the typical chimney installation. Always check your local codes.
Table from Metal-Fab, Inc.
Roof Pitch Minimum Height for gas chimneys, B-vent
Flat to 7/12 (305 mm) 1.0 feet
Over 7/12 to 8/12 (451 mm) 1.5 feet
Over 8/12 to 9/12 (610 mm) 2.0 feet
Over 9/12 to 10/12 (762 mm) 2.5 feet
Over 10/12 to 11/12 (991 mm) 3.25 feet
Over 11/12 to 12/12 (1218 mm) 4.0 feet
Over 12/12 to 14/12 (1524 mm) 5.0 feet
Over 14/12 to 16/12 (1829 mm) 6.0 feet
Over 16/12 to 18/12 (2134 mm) 7.0 feet
Over 18/12 to 20/12 (2286 mm) 7.5 feet
Over 20/12 to 21/12 (2438 mm) 8.0 feet
Metal-Fab B-vent (gas vent) instructions
For oil, wood or coal chimneys the top of the chimney must be at least 3 feet above the highest point of contact with the roof and at least 2 feet above the highest roof surface or other obstruction within 10 feet horizontally from the top of the chimney.
For more detailed installation instructions visit:
Metal-Fab Temp/Guard all-fuel chimneys
Metal-Fab L-vent for oil chimneys
We stock Metal-Fab B-vent for gas and Metal-Fab Temp/Guard for oil, coal and wood. Temp/Guard is rated for 2100F intermittent and 1000F continuous temperatures.