The Problem
The owners of a 1996 two-story in Greggs Landing noticed staining on the ceiling near the fireplace wall after two consecutive wet winters. The chimney itself looked fine from the street, but a closer look from the roofline told a different story. The concrete crown had developed a full transverse crack running across its width, and the joint between the crown and the outermost brick course had opened roughly 3/8 inch. Water was following that gap directly into the flue seat.
Below the crown, the stack joints above the roofline showed moderate recess averaging 1/2 inch. On a veneer chimney from the mid-1990s, that recess matters more than it would on older solid masonry - the brick wythe is thinner and moisture reaching the framing chase is a more serious consequence.
Our Solution
We demolished the failed crown with hand chisels, working carefully along the crown bed to avoid disturbing the uppermost brick course. The replacement crown was formed with a slight outward pitch and poured using a fiber-reinforced mix in two lifts. Once cured, we applied an elastomeric seal coat over the full crown surface and down onto the top two brick courses to create a continuous water barrier at the most vulnerable transition point.
Repointing of all stack joints above the roofline used Type N mortar. On Greggs Landing homes from 1996, the original mortar tends toward a light gray with minimal sand variation, so we tested a small batch against a protected joint before committing to the full mix. All joints were ground to 3/4-inch depth, cleared of dust, and moistened before packing in two lifts to prevent suction-pull from the brick. We also inspected visible veneer tie locations at the chimney base where the brick meets the roof surface, finding the ties intact with no corrosion requiring action.
Flashing at the roofline was cleaned, reseated at the step courses, and sealed with a polyurethane product compatible with the existing counter-flashing and shingles.
The Result
The ceiling staining stopped after the following rain season. The replacement crown shed water cleanly at its first freeze-thaw test, and the repointed joints showed no cracking at the 30-day inspection. The mortar color matches the lower unrepaired courses well enough that the repair zone is not visible from ground level.
Related: Chimney Repair Services | Vernon Hills Service Area
