What is the common term for the type of flashing used to waterproof joints between sloping roofs and vertical walls?

The common term for the type of flashing used to waterproof joints between sloping roofs and vertical walls is step-flashing. This flashing consists of individual pieces that are installed in a stepped manner alongside the roof's slope. Each piece overlaps the one below it, effectively channeling water away from the junction where the roof meets the wall. This design is particularly effective because it allows for proper drainage and helps prevent water from seeping into the joint, which could lead to leaks and structural damage over time.

Other types of flashing, like cap flashing, is used to cover the top edge of a wall or to serve as a cap over other types of flashing to protect them. Base flashing is typically used at the base of parapet walls or similar structures to direct water away from an area. Parapet flashing is specifically designed for waterproofing the top edge of a parapet wall. While each of these types of flashing serves important roles in a roofing system, step-flashing is specifically designed for the critical intersection between sloped roofs and vertical walls, which is why it is the correct answer to this question.