438 15th Street

What we found

438 15th Street arrived with the typical accumulation of issues we see on Park Slope brownstones that have not had serious facade work in 30+ years. Multiple layers of failed coatings, spalling at the lower facade where street-level salt does its damage, several courses of degraded mortar joints, and a stoop showing edge wear and minor riser delamination. Nothing catastrophic — but enough total deterioration that surface-only treatments would have been a waste of money.

The building was sound underneath. The brownstone was layered NYC sandstone of the era — soft, but salvageable with the right patching approach. The stoop had its original profile intact under the worn surface. The cornice was rusted but repairable.

The work

We stripped the failed coatings back to the underlying brownstone. We mapped each spalling area, tested the substrate, and patched in vapor-permeable layers color-matched to the surrounding stone. The mortar joints were selectively repointed with a lime-blend mortar — soft enough to flex with the building, hard enough to last decades.

The stoop was treated as its own project: edges reformed where the wear was deepest, risers patched and tooled to match the original profile, ironwork scraped, primed, and prepared for paint. The cornice was scraped, treated for rust, and recoated with a high-grade exterior system.

The result

The finished facade reads as continuous and original. From across the street, a visitor would not be able to tell which sections were patched and which are untouched original — which is exactly the standard. The building should not need significant facade work for another 20+ years if the new coating system is maintained as recommended.

Project gallery

A few additional views of the work at 438 15th Street.