What does the diagonal method refer to in roofing?

• A. The process of applying shingles in a straight horizontal row.
• B. A technique for trimming shingles at the corners.
• C. Roofing application method in which shingles are applied diagonally up the roof.
• D. The method of installing drip edge along eaves.

Answer: (C)

Diagonal method means applying shingles along diagonal lines up the roof rather than in straight horizontal rows. In practice, you start along one side near the eave and place the first shingles so their edges form a diagonal toward the ridge, then continue with each row along a parallel diagonal. This creates a pattern where the joints run diagonally, not horizontally, which is what distinguishes this method from the other tasks listed. Therefore, describing shingles as being applied diagonally up the roof best fits the diagonal method.