What is the minimum height that a vent must extend above a roof?

The minimum height that a vent must extend above a roof is typically set at 6 inches. This requirement is established to ensure that the vent is adequately positioned to prevent any potential obstruction by snow, roofing material, or other debris that may accumulate near the roofline. The height is also intended to facilitate effective venting, allowing for the proper escape of gases and maintaining the necessary air flow within the plumbing system. By extending at least 6 inches above the roof, the vent can effectively reduce the risk of backdrafts and maintain air pressure balance within the drain and venting systems, which is critical for proper plumbing function.

This standard helps to promote safety and efficiency in plumbing installations, ensuring that the system operates effectively without negative impacts on air quality or plumbing performance.