Which of the following is the correct minimum vent pipe height above the roof?

• A. 6 inches
• B. 18 inches
• C. 24 inches
• D. 12 inches

Answer: (D)

Vents through a roof must rise high enough to stay clear of weather and roof debris so they can vent properly. The air needs a path to the outdoors without being blocked by snow, rain, or leaves, and the vent must be easily seen and accessible for inspection. The minimum height specified is 12 inches above the finished roof surface, which ensures the vent remains open and effective in most weather conditions. Shorter heights, like 6 inches, risk being buried or blocked, while taller heights such as 18 or 24 inches are acceptable but simply exceed the minimum requirement. Therefore, 12 inches is the correct minimum.