When a built-up roof meets exterior walls, how much higher should the exterior wall extend above the roof at the intersection?

When a built-up roof meets exterior walls, how much higher should the exterior wall extend above the roof at the intersection?

• A. 20"
• B. 40"
• C. 10"
• D. 30"

Answer: (D)

When a built-up roof meets exterior walls, the wall should rise above the roof enough to allow proper weatherproofing at the joint. This extra height creates a space for the roof edge to be turned up, for counterflashing to be installed into the wall, and for a cap or coping to finish the top. About 30 inches above the roof surface is a practical target because it provides sufficient room for flashing details and wind-driven rain protection without adding unnecessary excess height. If the wall is too short, flashing and sealing can be ineffective and water can penetrate behind the roof edge; if it’s much taller, it adds cost with little extra benefit.

When a built-up roof meets exterior walls, the wall should rise above the roof enough to allow proper weatherproofing at the joint. This extra height creates a space for the roof edge to be turned up, for counterflashing to be installed into the wall, and for a cap or coping to finish the top. About 30 inches above the roof surface is a practical target because it provides sufficient room for flashing details and wind-driven rain protection without adding unnecessary excess height. If the wall is too short, flashing and sealing can be ineffective and water can penetrate behind the roof edge; if it’s much taller, it adds cost with little extra benefit.