The stack vent must extend above the high side of the roof by a minimum of:

The requirement for a stack vent to extend above the high side of the roof by a minimum of 6 inches is based on plumbing code and best practices to prevent issues such as the entry of water, snow, or debris into the vent system. Vent pipes are essential for maintaining proper air pressure within the drainage system, allowing wastewater to flow freely while preventing sewer gases from entering the building.

By extending the stack vent at least 6 inches above the roofline, it ensures that the vent is adequately positioned to function effectively without being obstructed by roof features or any environmental factors such as wind-driven rain or snow accumulation. This height also helps to minimize the risk of backpressure and enhances the overall ventilation of the plumbing system. Such regulations are in place to promote safe and efficient plumbing installations, contributing to both the performance and longevity of the system.