Valley flashing repair fixes the channel where two roof slopes meet. A valley carries more water than any other part of the roof, and when a valley runs down into the side of a chimney or a wall, it can send a flood of water straight at the flashing.
There are two common ways to build a valley. An open valley has exposed metal, usually a W-profile galvanized or painted steel liner with a center rib that stops water from one slope from running up the other side. A closed or woven valley has shingles running through it over an ice and water shield underlayment. We repair both, and we match what the roof already has unless the valley keeps failing.
The failures we see most are nails driven too close to the center of the valley, cut shingles with the corners left square so water runs sideways under them, and rusted metal under a pile of leaves and pine needles. In the Southeast, pine straw sitting in a valley holds water for days.
Where a valley dumps into a chimney, we often add a chimney cricket or extend the valley metal to push water around the brick. Call (833) 583-1301 to get a valley looked at.