What is roof flashing?
Thin metal strips installed at roof joints and penetrations to direct water away and prevent leaks into the building structure.
Roof flashing consists of thin metal sheets, typically made from aluminum, galvanized steel, or copper, that seal the seams and openings where the roof meets walls, chimneys, vents, skylights, and other structures. Its primary function is to direct water away from these vulnerable joints so it runs off the roof surface rather than pooling or seeping into the building.
Common flashing types include step flashing, which overlaps shingles along vertical surfaces, chimney flashing that wraps around chimney bases, vent flashing that seals pipe penetrations, and valley flashing that lines the V-shaped channels where two roof slopes meet. Drip edge flashing is installed along roof edges to control water runoff at the fascia. Each type is designed to fit its specific location and handle the water flow pattern at that point on the roof.
Proper flashing installation is critical because water intrusion at roof seams causes rot, mold, and structural damage. Flashing failure is a leading cause of attic leaks and moisture problems. The metal must be sloped correctly, overlapped in the right sequence, and sealed with roofing cement or caulk to stop water from working underneath. When roofing contractors in the Hartford Metro area perform replacements or repairs, they inspect and replace flashing as part of the job to ensure long-term water protection. Finding experienced installers who understand flashing details is essential for a roof that stays dry.