What is typically used to seal the roofing above a vent pipe?

A collar is typically used to seal the roofing above a vent pipe. This component, often made of rubber or a similar flexible material, is essential in preventing water from penetrating the roof around the vent pipe. It fits around the base of the vent and creates a waterproof seal, accommodating any movement that might occur due to temperature changes or building settling. This sealing is crucial to ensure the longevity of the roof and to prevent leaks that could lead to structural damage or costly repairs.

The other options do not serve this specific function in roofing. A truss refers to a structural framework that helps support the roof, while a beam is a horizontal structure used to support loads. A plate generally refers to a flat component in construction, but it does not provide the necessary sealing function required around vent pipes.