What should the valley of a roof look like?

A properly constructed roof valley should appear clean, uniform, and structurally sound, designed specifically to channel heavy volumes of rainwater smoothly down toward the gutters without obstruction. Depending on the architectural style of the roof, a valley generally takes one of three distinct appearances: an open valley features a clearly visible, smooth metal trough made of aluminum, copper, or galvanized steel running directly down the center of the intersection; a closed-cut valley has shingles from one roof plane overlapping continuously across the V-shape while the intersecting shingles are neatly trimmed back in a straight line; and a woven valley features alternating shingles interwoven seamlessly across the fold. Regardless of the specific style, a well-maintained valley should be entirely free of trapped organic debris, sagging sections, rust spots, or lifting shingle edges that could interrupt the natural flow of water runoff.