A roof valley is the internal angle formed where two sloping roof sections meet. It creates a channel that directs rainwater and melting snow down toward the roof’s drainage system, typically gutters.
Because valleys concentrate water flow, they are one of the most critical and vulnerable areas of a roofing system. Proper installation and waterproofing are essential to prevent leaks and structural damage.
Roof valleys are typically constructed using metal flashing, shingles, or specialized waterproofing membranes. The chosen method depends on roof type, slope, and climate conditions.
There are different types of valleys, including open valleys (where metal is visible) and closed valleys (where shingles overlap and conceal the valley liner). Each system has advantages in terms of durability and aesthetics.
Improperly installed or damaged valleys can lead to water penetration beneath roofing materials, resulting in rot, mold, and interior leaks. Regular inspection and maintenance are recommended, especially after severe weather events.
