What are plumbing jacks used for in roofing?

Plumbing jacks are specifically designed to fit around drain and waste vent pipes that extend through the roof. Their primary purpose is to create a waterproof barrier where these pipes penetrate the roofing material. By securely sealing around the pipes, plumbing jacks prevent water from entering the building at these vulnerable points.

The design of plumbing jacks incorporates flexible materials that can conform to the shape of the vent pipe, which allows for effective sealing against various weather conditions. This function is crucial for maintaining the integrity of the roof and preventing leaks that could lead to significant damage within the structure.

Other options do not capture the specific purpose of plumbing jacks. For instance, capping the roof edges typically involves different materials and techniques aimed at providing a finished look and preventing water penetration along the edges. Sealing shingles involves applying roofing adhesives or sealants which do not pertain to plumbing jacks. Supporting roof beams falls under structural framework rather than roofing penetration and waterproofing solutions. Thus, the choice that accurately reflects the role of plumbing jacks in roofing is the one regarding their fitting around drain and waste vent pipes.