Every once in awhile, I'm asked to use a V-crimped valley flashing profile. Typically, it's when I'm installing a metal roof where a valley is formed by intersecting roofs of different pitches. The rationale behind the V-crimp is that it will prevent the steeper roof runoff from running back up the adjoining shallow roof. I've seen it specified for asphalt shingle roofs, but I prefer to use a closed valley. The protruding ridge of the V-crimp can easily be damaged if someone accidentally steps in the valley. A cardinal rule is never to step in a valley, but accidents happen, and a misshapen V-crimp is unsightly and difficult to realign. I use a 10-foot brake to form the Vcrimp. The throat