As shingles are laid along an open valley, what is the width increase of the waterway per foot?

The correct answer reflects a crucial detail about the construction and installation of shingles in an open valley. As the shingles are laid along an open valley, there's a natural slope that directs water flow towards the valley. Specifically, the width of the waterway increases by 1/8 inch for every foot of valley area. This is due to the effective angle at which the shingles are installed, creating a gap that allows rainwater to flow more freely into the valley.

Understanding this increment is important for ensuring proper drainage and minimizing the risk of water pooling, which can lead to roof leaks and other structural issues. By following this standard, carpenters ensure that the shingles not only serve their purpose of protecting the roof from weather elements but also facilitate efficient water runoff through the roof valley system.