5 Signs Your Chimney Flashing Is Failing
Chimney flashing fails quietly — these five signs are usually visible well before a leak becomes obvious inside the home.
1. Water staining on the ceiling or wall near the chimney
Interior staining anywhere along the chimney chase, even a floor away from the roofline, is often the first sign homeowners notice. Water can travel a surprising distance along framing before showing up as a visible stain, so the stain's location doesn't always point directly at the leak's source.
2. Rust streaks on the flashing itself
Visible rust streaking down the chimney brick or siding from the flashing indicates the metal is deteriorating and likely no longer sealing properly, even if no active leak has developed yet. This is worth addressing proactively rather than waiting for a leak to confirm the problem.
3. Visible gaps or separation at the flashing
From ground level with binoculars, or during a professional inspection, gaps between the counter flashing and the chimney masonry, or lifted step flashing along the sides, are direct visual evidence of failure.
4. Deteriorated mortar joints around the counter flashing
Counter flashing is typically set into a mortar joint; if that mortar has crumbled or eroded, the flashing loses its seal even if the metal itself is intact. This is a masonry issue that affects flashing performance and needs to be addressed alongside any metal repair.
5. Daylight or moisture visible from inside the attic near the chimney chase
If your attic is accessible, checking directly around the chimney penetration for daylight, staining, or dampness gives you an early warning sign well before it progresses to a visible interior ceiling stain elsewhere in the home.