Key takeaways
- Flashing seals the joints where leaks love to start.
- Sealant dries out and metal rusts or lifts.
- Chimneys and walls are the usual hotspots.
- A small flashing repair can prevent big damage.
Shingles shed water, but flashing handles the joints, and joints are where leaks begin.
Where flashing lives
- Around chimneys
- Where roofs meet walls
- In valleys
- Around skylights and vents
- Along the roof edge
How it fails
- Sealant dries and cracks. The seal opens a gap.
- Metal rusts or lifts. Water slips behind.
- Nails back out. Fasteners loosen with movement.
- Settling. Houses move and joints open.
What to look for
Rust streaks, lifted edges, gaps, dried sealant and water stains near joints. A close look is best done by someone who can safely reach the area.
Case note: a small flashing repair now is cheaper than rotted decking later.