What is the minimum head lap allowed for slate shingles secured to a roof with a 6:12 slope?

The correct choice regarding the minimum head lap for slate shingles secured to a roof with a 6:12 slope is based on established roofing practices and building codes. Head lap refers to the distance the upper part of one slate shingle overlaps the lower part of the shingle above it.

For slate shingles installed on a roof with a slope of 6:12, a minimum head lap of 4 inches is recommended to ensure proper water drainage and prevent leaks. This measurement is critical because it helps to create a watertight roof. The 4-inch minimum allows for adequate overlap while still providing stability and alignment for the shingles in the presence of wind and rain, which is especially important in areas prone to severe weather.

Options that suggest lesser head lap measurements would not provide sufficient overlap for effective water shedding, potentially leading to water intrusion and associated problems. Proper head lap is a key part of the roof's design, particularly with materials like slate that can be susceptible to failure if not installed correctly. The recommendation for a 4-inch head lap aligns with industry standards for ensuring durability and effectiveness in roofing applications.