PS 247K — NYC School Construction AuthorityBrooklyn, NY
A combined strategy of replacement and renewal was employed to prevent hazardous cracking limestone shards from falling away from the building onto the ground at this elementary school designed in 1934 by Walter C. Martin. Through probes, it was confirmed that the pattern of cracking on numerous stones indicated systematic rusting of many steel anchors which held the stone to the building. In addition to the inherent porosity of the limestone itself, the joints between the stones were open in many places, and mildew had turned powdery. There was no flashing or system of weeps to enable moisture to exit the facade, and caulking around the windows was cracked and deteriorated. The replacement of existing limestone panels with new ones, re-anchoring of suitable existing panels and some patching of the damaged stone, was developed to address this hazard. Brick masonry laid in ornamental patterns was also included in the scope of work as part of ensuring a water tight condition.