Chimney Height Calculator
Chimney Height (2-10-3 Rule)
Calculate minimum chimney height per building code
Chimney Draft & Flue Size
Estimate chimney draft and recommended flue size
Formula
Min Height = Max(3 ft above penetration, 2 ft above roof within 10 ft) | Flue Area ≥ Fireplace Opening / 10
Frequently Asked Questions
What is the 2-10-3 chimney rule?
The chimney must extend at least 3 feet above the point where it passes through the roof, AND it must be at least 2 feet taller than any part of the building within 10 horizontal feet. This rule ensures proper draft and prevents downdrafts from nearby roof sections.
How tall should my chimney be for good draft?
Minimum 15 feet from the firebox or appliance connection to the top of the chimney for reliable draft. 20-35 feet is optimal. Chimneys under 12 feet may experience poor draft and smoke spillage.
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