How far should valley flashing extend from the centerline on each side?

The correct distance for valley flashing to extend from the centerline on each side is 11 inches. This measurement is critical for ensuring that water is effectively redirected away from the roof valley and into the gutters or drainage system. By extending the valley flashing sufficiently on both sides, it minimizes the risk of water infiltration and potential damage to the underlying roofing materials or structural components over time.

This standard has been established to promote proper drainage and safeguard the integrity of a roofing system, particularly in regions that may experience heavy rainfall. The specified extension of 11 inches allows for enough overlap with the adjacent roofing materials, ensuring that any water that does flow down the roof is effectively channeled away from potential entry points.

Understanding these specifics helps contractors ensure that their work meets both building codes and industry best practices, thereby enhancing the longevity and performance of the roofing system they are installing.