How Much Chimney Height Do I Need Above the Roof?
Chimney height is the most important factor that can affect the overall performance of a wood stove and whether your installation is safe. For traditional construction, the “3-2-10 Rule” is in force that determines how high chimneys have to be above the roof. For RVs, vans, buses, and boats, we suggest using shorter and detachable chimneys.
The 3-2-10 Rule
The openings for chimneys above the roof should be at least 3 feet above the roof line or 2 feet above any part of the building that is higher. For most small structures, such as small cabins and tiny homes, the tallest part of the structure is where chimneys should be placed. In this case, chimneys must be 2′ above the peak or 3′ above the roof line, whichever one is higher.
For larger structures, the result depends on the pitch of the roof. For example, in a building that has a flat or shallow pitch, chimneys must be 3 feet above the point where they pass along the roof line. For buildings that have steeply pitched roofs, the chimneys must be 2′ above the highest part of the roof.
Why Is the Height of Chimneys So Important?
Taller chimneys create a stronger draft. One factor that will dictate the strength of the draft created by a flue system is the difference in air pressure from the firebox and the opening of the chimney. Because air pressure is lower the higher the altitude, a taller column of rising air will pull harder on the air that is below it; increasing the height of the chimneys will increase the draft. Traditionally, homes have at least 15 feet of vertical height between the chimneys and the firebox. Most tiny structures are not tall enough to support a 15-foot flue, so it is important to have as much height as possible.
If you would like to make an appointment for a professional chimney service, please contact HDL Construction LLC at (201) 375-5437 now! We are happy to be of assistance if you live in the Hasbrouck Heights, NJ region.