Maintenance · 5 min read
Chimney Leaks: Diagnosis and Permanent Repair
Published
Chimneys are the second most common leak source we chase, and the repair is frequently masonry work as much as roofing work.
Four entry points
Failed counterflashing at the mortar joint, cracked crown at the top, deteriorated mortar joints in the stack itself, and a missing or ineffective cricket on the upslope side of a wide chimney.
Diagnosis
A hose test, run in stages from the bottom up with someone watching in the attic, isolates the entry point. Start at the base flashing and work upward, waiting several minutes at each stage.
Doing it right
Counterflashing should be cut into a reglet in the mortar joint and sealed, not surface-mounted with caulk. Crowns should be cast concrete with an overhang and drip edge, not the thin mortar wash most chimneys were built with.
When to consider removal
If the chimney serves nothing — the furnace was converted, the fireplace is decommissioned — removing it below the roof line and reroofing over the opening permanently ends the maintenance cycle and often costs less than a full rebuild.
If any of this applies to your own home, our emergency roof repair crews handle it every week, and you can see how we work in your area on our Troy, Ohio roofing page. Inspections and written estimates are free either way — call 937-749-7767.