The Problem
The homeowner’s annual roof inspection flagged mortar deterioration on all four faces of the chimney. The south and west faces showed the worst damage - joints were recessed over 1/2 inch and several had open voids. The chimney crown was still intact but showed hairline cracks that would need attention within 2-3 years.
The chimney had not been repointed since original construction in 1962 - 63 years of Chicagoland weather. While that is actually decent longevity for mortar joints (typical life is 25-50 years depending on exposure), the joints were clearly past their useful life and allowing water entry into the chimney structure.
Our Solution
We accessed the chimney from the roof using proper fall protection equipment. All mortar joints on all four faces were ground out to a minimum depth of 3/4 inch. The existing mortar was a standard Type N Portland-lime mix typical of early 1960s construction.
The replacement mortar was a Type N mix color-matched to an unexposed joint sample taken from inside the flue cleanout door. This interior sample showed the original mortar color before 60+ years of UV exposure and weathering had lightened the exterior joints.
We packed all joints in two lifts and tooled each with a concave profile to match the original joint style. The hairline crown cracks were sealed with a flexible crown sealant (not a permanent fix, but buys time until a crown rebuild is needed).
The Result
The repointed chimney is now fully sealed against water penetration. The mortar color matches the original warm gray tone. The homeowner was advised that the crown will need a full rebuild within 2-3 years, and we documented the crown condition with photos for their records.
