head lap
Isaac Kremer/ November 23, 2025/ / 0 comments
The overlap of a roofing material, like a slate tile or shingle, on the course two rows below it, creating a watertight seal by preventing water from getting underneath. It is the distance from the upper edge of a lower course to the exposed surface of the next course up, and the correct head lap is crucial for weatherproofing the roof. The required head lap varies based on the roof’s slope, with lower slopes needing a greater overlap. (Kremer, 2025)