Tuckpointing is not cosmetic. Mortar joints are designed to be the sacrificial element in masonry — softer than the brick, so that movement and moisture take the joint rather than the unit. When those joints fail, water has a direct path into the chimney, and from that point the damage moves from something that can be raked out and replaced to something that involves cutting brick out. Repointing in time is the difference between a joint repair and a rebuild.
What failing mortar looks like
Joints that are recessed well behind the face of the brick. Mortar you can pick out with a screwdriver or, in bad cases, a fingernail. Sand collecting on the roof or at the base of the chimney. Visible gaps and open head joints. Any of those means the joint is no longer keeping water out.
Where the joints have failed on a weather-facing elevation, the chimney does not need a crack anywhere to leak. The wall itself has become the route.
Repointing properly
The distinction that matters is between repointing and smearing. Done properly, the failed mortar is cut out to an appropriate working depth — deep enough that the new material has something to key into — the joint is cleaned of dust and loose material, and new mortar is packed in and tooled to match the original profile.
Done badly, new mortar is spread over the face of the old failed joint. It looks fine for a season. It has no depth, it is not bonded, and it comes away.
Matching the mortar to the brick
This is the part that gets old chimneys damaged. Older brick is generally softer and more permeable than modern brick, and was laid in a softer lime-based mortar. Repoint it with a hard modern cement mortar and the joint becomes stronger than the units around it. Thermal movement and moisture then have to go somewhere, and they go into the brick face instead of the joint — so the repair causes exactly the spalling it was meant to prevent.
ABC Chimney Solutions selects the mortar based on the existing masonry and the project rather than using one mix on everything, and makes a real effort to match the existing color and joint appearance at the same time.
Why we sometimes recommend a slightly wider area
Occasionally only a few joints have fully failed, but the mortar immediately around them is visibly close behind. Repointing a slightly larger area now is often the cheaper outcome, because the alternative is repeating the same setup, the same access and the same visit within a couple of years. We will explain when that applies and let you decide.
Weather and timing
Mortar has to cure. ABC Chimney Solutions schedules masonry work around suitable temperatures and normally looks for a rain-free window of roughly two to three days, so the repair has a fair chance of curing correctly rather than being rushed in between showers.
Where it sits among the options
Timely tuckpointing and repointing is the cheapest thing on the masonry list and the one that prevents the most. Left long enough, it becomes masonry restoration — cutting out and replacing units as well as joints — and left longer still it becomes a rebuild.
Adding vapor-permeable waterproofing after repointing keeps liquid water out of the masonry while still letting it dry, which is the pairing that gets the most out of the work.
Frequently asked
How do I know if my chimney needs repointing?
Look for joints recessed behind the brick face, mortar that crumbles when picked at, sand collecting at the base, and open gaps. Any of those means the joint has stopped keeping water out, and ABC Chimney Solutions would recommend repointing before the brick starts taking the damage instead. Learn more about this service.
Can you match the existing mortar?
ABC Chimney Solutions selects the mortar to suit the existing masonry and makes a strong effort to match the color and joint profile. On older brick that suitability matters as much as the appearance — too hard a mortar damages soft brick. Learn more about this service.
Is repointing a permanent fix?
It restores the joints to a working condition and, on sound brick, buys a great many years. It does not stop water arriving from a failed crown or an uncapped flue, which is why ABC Chimney Solutions addresses those at the same time. Learn more about this service.