Chimney Flashing & Leak Repair in Maryland

Warning signs include cracks in the crown, crumbling material at the crown edges, spalled or flaking brick faces, missing mortar joints, efflorescence (white salt deposits) on exterior brick, water stains inside the house adjacent to the chimney, rust on the damper, and any visible lean or step crack in the chimney structure. Most repairs are far less expensive caught early.

Crown repair is the highest-leverage chimney repair dollar a homeowner can spend. The crown is the slab at the top that sheds water away from the chimney masonry. When the crown fails, water flows directly into the chimney chase, damaging every component below. Fixing the crown stops the damage at its source.

CrownCoat is a flexible elastomeric coating applied over an existing intact crown with hairline cracks. It seals the cracks, stays flexible through freeze-thaw, and carries a 15-year warranty. A full rebuild is required when the crown is structurally compromised, missing material, or was built without proper overhang and drip edge. Rebuilds use poured concrete with mesh reinforcement and last 40-60 years.

ChimneySaver is a vapor-permeable masonry repellent. It lines each masonry pore with a hydrophobic chemistry that beads liquid water on contact while still allowing water vapor to pass through in either direction. Silicone sealers and paint coatings trap vapor inside the masonry, and the first freeze after application spalls every brick that had moisture inside. ChimneySaver is the right category. Silicone is wrong.

Almost certainly yes. An uncapped flue lets rain, snow, animals, embers, and downdrafts into the chimney. Once water enters the flue, it dissolves mortar between clay tiles, rusts the damper, and spalls the smoke chamber. A $400 stainless cap installed today routinely prevents $4,000 in liner damage three winters from now.

Most chimney leaks are flashing leaks, and most flashing leaks are misdiagnosed. We diagnose root cause (hose test, attic inspection, photo documentation), then rebuild step and counter flashing properly with ice and water shield underneath. Tar patches are stopgaps that fail within 2-4 winters. Proper flashing lasts the life of the roof.

Tuckpointing failed mortar joints runs $450-$2,495 depending on linear footage and access. We grind out failed joints to a minimum depth of 3/4 inch, brush clean, dampen, and re-tuck with Type N or Type S mortar matched to the original color and profile. Historic chimneys with lime-rich joints use historically appropriate mixes.

A cricket (also called a saddle) is a small peaked structure built on the upslope side of the chimney to divert water and snow around it. The IRC requires a cricket on any chimney wider than 30 inches measured perpendicular to the roof slope. Many older Maryland chimneys lack crickets and suffer chronic upslope leaks as a result.