Historic Co-op Allowed to Replace Terra Cotta with Cast Stone

The 12-story, century-old co-op in the Upper West Side Historic District was due for its mandatory cycle under the Facade Inspection and Safety Program (FISP). When workers started using sounding hammers to perform hands-on inspections of the terra cotta pieces on the facade, they were in for a surprise. It turned out that nearly 500 pieces – window jambs, lentils, arches, and decorative scrollwork – needed to be replaced. But with only two companies in the country producing terra cotta, the project could have dragged on indefinitely.

What’s a co-op board to do? This one turned to its contractor, Central Construction, who suggested that replacing the faulty terra cotta with cast stone replicas would speed up the project and reduce costs. But in February 2017, the Landmarks Preservation Commission (LPC) rejected the idea, insisting, as it usually does, that only terra cotta can replace terra cotta.

A co-op board member then asked the corporation’s engineer, Jamey Ehrman of RAND Engineering & Architecture, to contact the Landmarks Conservancy, a nonprofit that supplies low-interest loans to historic buildings. Blaire Walsh, the conservancy’s project and outreach manager, agreed to get in touch with the LPC to plead the co-op’s case.

“I used to work at the commission, so we speak the same language,” Walsh says. “They wanted an accurate number of how many pieces of terra cotta needed to be replaced. We got Rand to update their drawings and show that the faulty terra cotta was less than 5 percent of the facade area.” The LPC reversed itself and approved the cast stone in February 2018. The job could finally begin.

“She was very proactive,” Ehrman says of Walsh. “She understood the predicament we were in – terra cotta across the city is starting to fail at the same time. With the supply logistics, we’ve got a real problem, but the terra cotta isn’t stepping up to solve it. Blaire argued to the LPC that cast stone is a satisfactory replacement.”

Unlike terra cotta – clay that’s placed in a mold, then dried and fired in a kiln – cast stone is concrete that’s poured into custom-made molds and allowed to cure. It’s cheaper and faster to produce than terra cotta. To many purists, though, it’s an inferior substitute.

“The purists think only terra cotta should replace terra cotta,” Ehrman says. “In a perfect world, we would all use terra cotta. But it may not be possible to match terra cotta exactly, 100 years after the original was made, and cast stone might look virtually identical. I’m an engineer, and the project must always move forward. Cast stone became a reasonable way to do that.”

This job may be a sign of greater flexibility on the part of the LPC. “I think this project is a change,” says Walsh. “The LPC is being more sensitive about substitute materials, such as cast stone to replace terra cotta or actual stone. Or fiberglass to replace wooden or sheet-metal cornices.”

As the Upper West Side job winds to a close, Ehrman is confident that the client will be satisfied. “We sounded everything and replaced everything that was suspect,” he says. “I can’t say with 100 percent certainty that there won’t be any repairs required on the next (five-year) FISP cycle, but it’s unlikely it’ll be on the magnitude of the work we’re just completing.”

PRINCIPAL PLAYERS – ENGINEER: RAND Engineering & Architecture. CONTRACTOR: Central Construction. CAST STONE SUPPLIER: D’Amelio Brothers.