Repointing is cutting out deteriorated mortar to a sound depth and refilling the joint with fresh matched mortar. You need it when the joints have receded, softened, or started shedding sand — the quick field test is scraping a joint with a screwdriver, and if the mortar gives up sand easily while the brick around it stays solid, it is time. The reason not to wait is that open joints admit water, and once water is behind the brick face the freeze-thaw cycle begins spalling it, which turns a mortar job into a brick-replacement job.

Once a brick has lost its outer face it cannot be restored — the hard fired surface that made it weather-resistant is gone, and the exposed core will keep absorbing water and shedding layers. The fix is cutting the unit out and setting a replacement. Sealers and coatings are sometimes marketed for this and generally make it worse, because they trap the moisture inside the brick rather than letting it evaporate. The useful move is replacing the failed units and repointing the surrounding joints so no more brick is exposed.

Mortar sets in hours but continues gaining strength for weeks, and it needs temperatures holding above roughly 40°F while that happens. In the Philadelphia area that means repointing and brick-laying work runs from spring through late autumn, and a cold snap mid-job can mean pausing rather than pushing through. Freshly finished joints also look noticeably lighter than they will end up, so a new section typically blends into the surrounding wall over the first few months rather than matching perfectly on the day the scaffold comes down.

That is movement, not weathering, and it is more urgent than a mortar problem. On a freestanding or retaining wall, bulging usually means water pressure has built up behind it because the drainage failed or was never installed. On a house wall it can mean a failed lintel over an opening, corroded wall ties, or settlement below. In every case the wall is telling you a structural condition has changed, and the repair is a rebuild of the affected section after the cause is addressed — repointing a leaning wall accomplishes nothing.

Be careful with both. High-pressure washing on older Delaware County brick can strip the fired face and blast out already-soft mortar, turning a cleaning into a repointing job. Gentle low-pressure cleaning with the right detergent is usually the right approach. Sealers are the bigger risk: brick is meant to breathe, absorbing and releasing moisture, and a film-forming sealer traps water inside the unit where it freezes and spalls the face from within. Sound joints, working flashing, and proper drainage protect brick far better than any coating.

K&S Masonry Restoration is based in Brookhaven, PA and works throughout Delaware County and the Philadelphia suburbs, including Philadelphia, Havertown, Springfield, Drexel Hill, Chester, Wayne, Radnor, and Ardmore, plus Montgomery and Chester Counties. If you are unsure whether your address is in range, call (610) 990-1379 and ask — it is a quick answer.