Plumbing roof vents must extend a minimum of how far above the roof?

Plumbing roof vents are critical for ensuring proper drainage and preventing sewer gases from entering the home. According to plumbing codes, the minimum height requirement for these vents is set to ensure they effectively function without being obstructed by roof surfaces, snow, or other potential barriers.

Extending the vent a minimum of 12 inches above the roof provides adequate clearance to prevent backdrafts or blockages caused by wind or ice accumulation. This elevation helps to maintain proper ventilation for the system, promoting good air flow and preventing issues like stagnant air or sewer gas backflow into the building. Furthermore, having the vent raised sufficiently above the roofline minimizes the risk of water pooling around the vent opening, which could compromise its function and lead to leaks or other plumbing issues.