ASK AN EXPERT: What Is Roof Flashing?

Q: What is roof flashing, and why is it important?

A: Roof flashing is a thin, weather-resistant material—usually aluminum, galvanized steel, or copper—that’s installed in vulnerable areas of your roof where water is most likely to penetrate. These spots include around chimneys, skylights, vents, roof valleys, and anywhere the roof meets a vertical wall. The job of flashing is to create a watertight barrier and direct rainwater, melting snow, or debris safely down the roof and into the gutters.

Without properly installed or maintained flashing, water can easily seep into seams and gaps, causing leaks, wood rot, insulation damage, and even structural problems over time. In fact, damaged or missing flashing is one of the most common sources of roof leaks. That’s why flashing isn’t just an accessory—it’s a critical part of your roof’s defense system. Regular inspections and timely repairs help ensure your flashing continues to protect your home or building for years to come.