What is the role of a drip edge in a roof system?

• A. For decoration.
• B. To hold shingles in place.
• C. Directs water away from underlying structure.
• D. To seal nails.

Answer: (C)

The main idea is to control water flow at the roof edge. A drip edge provides a clean, outward-facing edge that directs run-off away from the underlying structure and toward the gutter, helping water shed cleanly off the roof rather than seeping behind the fascia, into the decking, or underlayment. This protects the roof deck, fascia, and interior from rot and moisture intrusion and supports proper gutter performance by giving water a clear path off the roof.

It’s not for decoration, it doesn’t hold shingles in place, and it doesn’t seal nails. Those roles belong to aesthetics, fasteners, and flashing/sealants, respectively.