What is valley flashing used for in roofing?

Valley flashing is specifically designed to be installed in the "V" area of a roof valley, which is the point where two roof slopes meet and channel water down toward the eaves. The purpose of valley flashing is to prevent water from entering the roof system at this vulnerable point, where there is increased risk of leaks due to the accumulation and flow of water. It acts as a waterproof barrier, effectively directing water away from the seams where the roof planes intersect while ensuring that any water runoff is efficiently diverted to the gutters.

The function of valley flashing is not related to insulation, the overall strengthening of the roof structure, or merely directing water away without regard to its placement. Each of these other aspects has its own solutions in roofing, but valley flashing's role is crucial for maintaining the integrity of roof valleys and preventing potential water damage.