Tuckpointing is the process of repairing deteriorated mortar joints in brick or masonry. Around a chimney or masonry wall, it can be just as important as the flashing because water can enter through failed mortar joints above the roofline.
Why It Matters
Chimney flashing and wall flashing are designed to shed water at the roof-to-masonry transition. If the mortar above or around that flashing is cracked, loose, or missing, water may still find a path behind the flashing or into the masonry. In that situation, the leak may look like a roofing problem even though the masonry is part of the issue.
Common Problems
Common problems include cracked mortar joints, loose brick, open gaps above counter flashing, sealant smeared over failing masonry, metal flashing set into deteriorated joints, and water entering through the chimney face rather than the roof surface.
Building Codes & Industry Standards
Chimney and wall flashing details need to work with the condition of the masonry. Counter flashing is often tied into mortar joints or masonry cuts, so the surrounding brick and mortar must be sound enough to support a durable water-shedding detail. Masonry repairs should follow appropriate masonry practices and local requirements.
Exterior Echelon Notes
Exterior Echelon looks at both the flashing and the masonry condition when evaluating chimney leaks or masonry wall transitions. A good flashing detail cannot always overcome failing mortar, so tuckpointing may need to be addressed before the flashing system can perform the way it should.
