What is the purpose of aluminum valley flashing?

Aluminum valley flashing is primarily designed to prevent water infiltration in roofing systems. Valleys are the areas formed where two sloping roof sections meet, creating a channel that directs water runoff. Without proper flashing in these areas, water can seep underneath the roofing materials, leading to leaks, wood rot, mold, and other moisture-related issues within the structure. The aluminum material is particularly effective because it is durable, resistant to rust, and can conform well to the roofing surfaces, ensuring a tight seal that directs water away from vulnerable areas. This protective function is critical for maintaining the integrity and longevity of both the roofing system and the building itself.