How high must a chimney terminate above a roof to ensure proper venting?

A chimney must terminate at least 3 feet above the highest point where it passes through the roof to ensure proper venting. This height is crucial for preventing backdrafts, ensuring that gases and smoke can escape freely, and reducing the risk of chimney fires or carbon monoxide accumulation. The 3-foot guideline helps ensure that the chimney's exhaust is carried away from the roof and any nearby structures, minimizing the chance of dangerous fumes re-entering the building or causing other safety hazards.

Additionally, if the chimney is within a certain distance from the roof's peak or adjacent structures, it may need to be taller than 3 feet to create a proper draft and prevent downdrafts. This is part of the overall safety and efficiency required for venting systems in homes and buildings.