When using lead as a flashing on a roof drain, how far must the flashing extend beyond the outer circumference of the stone guard clamping ring?

The requirement for lead flashing to extend a specific distance beyond the outer circumference of the stone guard clamping ring is designed to ensure that water is effectively diverted away from the roof drain. Extending the flashing by 12 inches provides a sufficient barrier against water penetration, which is critical for preventing leaks and protecting the roofing structure. This distance is generally based on industry standards and best practices that take into account the expected movement of water and the potential for wind-driven rain, ensuring that the flashing covers areas where water could pool or run down.

The other choices represent distances that are either unnecessarily excessive or inadequate based on standard roofing practices. A shorter extension may not adequately protect against water infiltration, while excessive lengths could complicate the installation without providing additional benefits. Thus, a 12-inch extension strikes a balance between effectiveness and practicality for proper rooftop drainage systems.