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Facade restoration for a New York City landmark is nearly complete
By Alex Ulam

	At Shepard Hall (above), masonry is replacing terra-cotta elements that were load bearing (below). Before-and-after photos (two bottom) show the new GFRC panels in action.
	Photography: Courtesy Stein White Nelligan Architects

This spring, a long-term preservation project for one of Manhattan’s most ornately decorated buildings will be drawing to a close. The disintegrating terra-cotta facade of Shepard Hall, the immense neo–Collegiate Gothic structure at the City College of New York, is being replaced by glass-fiber-reinforced concrete (GFRC). The effort is one of the largest terra-cotta replacement projects ever undertaken.

Designed by architect George Post and completed in 1907, Shepard Hall was on the verge of structural failure in 1986 when Stein White Nelligan Architects was hired to repair its terra-cotta elements, which comprised about 15 to 20 percent of the facade. The material began to crack and crumble in the 1930s, allowing water to seep through, says Carl Stein, a firm principal. Much of the terra-cotta was load bearing, with some pieces extending several feet into stone walls. As a result, its failure further undermined the building’s integrity. “It was either do something or demolish the whole building, because it was going to fall down in 10 or 15 years,” he says.

Back in 1986, the most durable GFRC available was a low-cost material with a limited grayish palette used chiefly in industrial structures. Stein began exploring it as an option for Shepard Hall, knowing that using terra-cotta or typical substitutes such as cast stone or architectural precast concrete for the building’s facade would have been cost prohibitive. He worked with manufacturer Cem-Fill to improve GFRC’s resistance to acid rain and UV light (which had been problems in the past) and make the material more flexible for pigmentation. Stein says the improved GFRC is one of the most durable, convenient materials to use in historic reconstruction.

About 72,000 pieces of terra-cotta, including more than 3,000 exterior sculptural ornaments, are being replaced with 0.5-inch-thick GFRC panels. They will serve as a decorative skin and rain screen for Shepard’s facade. Supporting the panels is an adjustable skeleton of galvanized-steel brackets. This substructure will make future repairs and restorations easier, Stein says, and also eliminates compressive loads in the outer skin, since the joints can absorb movement between the GFRC panels. New interior structural masonry will replace the terra-cotta elements that were load bearing.

Some preservationists and engineers have expressed doubts about the long-term durability of GFRC. But Stein says the panels being used will actually last longer than other materials.

Using GFRC allowed Stein to recreate ornamental features in detail, which would have been expensive and complicated had other materials been used. The large dog sculptures at Shepard Hall, for example, weigh only about 500 pounds in GFRC, compared to 3,000 to 4,000 pounds had they been made of cast stone. And the firm was even able to replicate irregularities in the original terra-cotta panels. “We had to avoid making things too perfect,” Stein says. “We didn’t want Shepard to look like a fake Gothic Revival building.”

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