At what rate does the waterway width increase for shingles laid along the sides of an open valley?

The increase of the waterway width for shingles laid along the sides of an open valley is understood to be 1/8 inch per foot. This measurement is crucial for ensuring proper water drainage and preventing potential water pooling, which can lead to leaks and other issues in roofing applications.

When shingles are positioned along the valley, they must be installed in such a way that they effectively channel water down into the valley. The specified increase in width ensures that each shingle overlaps adequately with the next, providing a lip that helps guide water into the valley rather than allowing it to cascade off the edges, which could compromise the roof’s effectiveness.

In carpentry and roofing, precise dimensions such as this help maintain the integrity of the structure and ensure longevity through proper water management. Understanding this concept is vital for anyone involved in roofing installation and maintenance.