What is the role of roof penetrations like vent pipes and skylights during shingle installation?

• A. They must be flashed and sealed properly to create a watertight connection with the shingles and flashing assembly.
• B. They should be left unsealed to create ventilation.
• C. They require only nails, no flashing.
• D. They are optional.

Answer: (A)

Penetrations in a roof create potential leak points, so they must be flashed and sealed properly to form a watertight connection with the shingles and the flashing system. Vent pipes get a flashing boot or collar that seals around the pipe and is integrated with the surrounding shingles, using step flashing and counter-flashing to direct water away from the joint. Skylights require proper curb flashing and a coordinated layout so the flashing around the skylight blends with the surrounding shingles, often with side and end flashing plus counter-flashing to keep water from seeping in. The goal is to channel water down and off the roof, not into gaps around the penetration. Relying on nails alone or on sealant without proper flashing leaves the installation vulnerable to leaks and long-term damage. Proper flashing around penetrations is essential for a durable, watertight roof.