A woven valley is a traditional method of installing shingles in the valley by interlacing the shingles as you go up the roof. This method is fine when installing the traditional strip shingles. However, it creates a problem with Architectural shingles. These shingles are thicker and the weave causes them to “bridge” the valley resulting in a condition that allows water to migrate underneath the shingles. The cut valley prevents this condition and provides a cleaner aesthetic appearance.