What Causes Roof Flashing Failure?

Flashing protects valleys, roof edges and other parts of the roof that’s vulnerable to moisture intrusion. But why is it important to ensure that flashing doesn’t fail?

What Is Flashing?

Flashing is installed over breaks on the roofing plane to help prevent water infiltration. Most types of flashing are made from metal strips, with different profiles depending on which parts of the roof it will be used.

Valley flashing is installed on roofing valleys where rainwater from meeting slopes can cause cross-infiltration. It features an inverted “T” profile, with the vertical fin acting as a barrier. Some roofing systems feature flashing with material that’s similar to asphalt shingles that create a cleaner look.

Continuous and step flashing protect the base of dormers and similar structures that project from a roof slope. Continuous flashing is installed on the side of the projection that’s parallel to the roof while step flashing is installed in “steps” that follow the shingles along the roofing slope.

Drip edges are long strips of flashing that protect the roof edge and typically have an inverted “L” profile, though some roofing systems use a right side-up “T” drip edge. Rainwater can infiltrate the roof edge through water surface tension, and drip edges extend the roof edge downward and route the rainwater into the gutters.

Rubber boots are made of rubber and are shaped like traffic cones. They’re installed on the base of vent pipes and similar cylindrical protrusions. The tip of the cone is cut to fit the pipe and sealed afterwards.

How to Prevent Flashing Failure

Flashing is exposed to the same conditions as the roof and can, therefore, be damaged by high winds and impact from hailstones and airborne debris. Flashing can become dislodged, bent or knocked clear off the roof. Extreme temperatures and ultraviolet (UV) rays can also cause rubber boots to crack and turn brittle over time. This is why you need to pay attention to flashing when routinely inspecting your roof and especially after a storm. They will need to be replaced by your roofing contractor even when the rest of the roof looks fine.

Investing in a quality roofing system can also help prevent flashing failure. In addition to using heavy-duty materials, quality roofing systems typically include accessories – which include flashing – in their warranty coverage.

Renovation Team is your leading provider of roofing repair and installation services. Give us a call at (636) 428-3634. You can also fill out our contact form to schedule an appointment. We serve customers in St. Louis, St. Charles and Creve Coeur, MO.