Short Answer
Flashing is a component used to direct water away from vulnerable intersections and penetrations. Examples include step flashing, counterflashing, valley flashing, chimney flashing, pipe flashing, wall flashing, and drip edge. Flashing is one of the most critical parts of water management on a roof.
Detailed Explanation
Flashing is the metal (or sometimes rubberized) material installed at every point where the roof plane changes direction or is penetrated. Every time a roof meets a wall, a chimney, a vent pipe, a skylight, or a valley, there's a transition that needs flashing to direct water away from the gap. Without proper flashing, water would run straight into these joints and into the home. Flashing is arguably more important than shingles for preventing leaks — a roof with excellent shingles and poor flashing will leak, while a roof with average shingles and excellent flashing will often perform well. That's why flashing quality and installation are critical evaluation points in any roof replacement.
Why It Matters
Most roof leaks originate at flashing failures, not shingle failures. Flashing quality is the single biggest differentiator between a roof that lasts and one that leaks.
Common Mistakes
- ✕Reusing old, deteriorated flashing during roof replacement
- ✕Not asking what flashing will be replaced
- ✕Assuming flashing is included when it's not specified in the proposal
Questions to Ask Your Contractor
- ?What flashing will be replaced vs. reused?
- ?Will new step flashing be installed at all roof-to-wall transitions?
- ?Will chimney flashing be replaced or reused?
- ?What material is the flashing made of?