Chimney Services
Chimney mortar repair in Lock Arbor, in detail
Damp joints with no standing water
Brick that is bone dry wicks water out of new mortar too fast, and the bond suffers. Technical Note 46 recommends dampening the joints before repointing but letting the brickwork absorb all surface water first. The Park Service brief puts it the same way: damp at the time of filling, with no standing water present.
Getting that balance right depends on the day, the sun on each face of the chimney and how absorbent the brick is. Our crew adjusts as the work moves around the chimney, which is one reason careful repointing on a home in Lock Arbor is never rushed to fit a clock.
Tooling new joints at thumbprint hardness
Timing the tooling decides both how well a joint sheds water and how it looks. Technical Note 7B describes thumbprint hard as the point where a thumb leaves an impression but picks up no mortar. Tooled too early, joints smear and can turn out lighter in color. Tooled too late, the surface cannot be consolidated against the brick.
The Park Service brief adds that joints tooled when too hard can show dark streaks known as tool burning. On a chimney the faces set at different speeds depending on sun and wind, so our crew checks each area before tooling it.
Letting new mortar joints weather in
Even a well-matched repair looks newer than the joints around it for a while. The Park Service brief explains that new mortar is matched to the unweathered portion of the old, and that sand shows more on old joints as their surface erodes. Its advice for a properly matched mortar is to let it age naturally.
The same brief generally advises against staining new mortar to force a match, because old and new joints may weather at different rates. We tell you what to expect in the first months, so the fresh look of a new repair on your Lock Arbor chimney is not mistaken for a mismatch.
Chimney cracks that point to movement
Some cracks come from the chimney moving rather than the mortar wearing. A crack that steps diagonally through several courses, runs through brick as well as joints or keeps widening is a different problem, and Technical Note 46 places structural cracks outside ordinary maintenance, calling for professional investigation of the cause.
Filling those cracks with new mortar would hide the symptom for a while and leave the cause in place. When our specialists see signs of movement on a chimney in Lock Arbor, we explain what we found, and the options may include rebuilding part of the stack. Tuckpointing is recommended only where the masonry is stable.
