Audubon Terrace is a remarkable but little-known Beaux-Arts ensemble in New York’s Washington Heights neighborhood. When the American Academy of Arts and Letters—housed on the terrace in a 1923 McKim, Mead, and White building—purchased the neighboring American Numismatic Society building in 2005, it struggled with how to bridge the 12-foot gap between the two landmarks. With no practical way to create an underground link, the organization charged house architect James Czajka of JVC Architects with creating a structure to connect the buildings above ground, without detracting from the existing architecture.
The result is a carefully detailed 144-square-foot connector, made almost entirely from low-iron glass. “It really is a Swiss watch,” says Czajka, who was assisted with the detailing by Henry N. Cobb (a member of the academy and the association’s building committee) and Michael Flynn of Pei Cobb Freed & Partners. Three layers of the material are laminated together to form 1½-inch-thick glass trusses that support the 1-inch-thick glass shed roof. Each end wall is made from a single sheet of glass 10 feet wide—the largest that could be manufactured—and 16 feet tall, and trimmed with a bronze cap around the edges that will limit exposure and help to prevent delamination over time.
To make up the remaining foot of space on either side of each end wall, a system of bronze-clad steel gutters was developed to support the glass roof and handle stormwater runoff. The decision to angle the sheds toward the existing buildings instead of to the front and back of the Glass Link raised a few eyebrows, but the reasoning is very practical. “If we had that shed come to the front and back,” says Czajka, “there would be constant rainwater and streaks.”
The glass also extends to the floor, which consists of a grid of 16 glass squares made from multiple sheets of laminated glass with a white translucent interlayer. The glass sits on a series of pedestals on top of the underfloor structure, and a media grid—composed of 2-inch-square tubes that accommodate light fixtures—runs in the gap created between the structure and the glass. “We haven’t played light twister yet,” says Czajka, referring to the fact that the lighting has yet to be finalized. For now, the link is lit at night by fluorescent fixtures from the office below.
Despite the use of modern materials, Czajka understood the need to dialogue with the classically inspired 1923 building. The Glass Link’s end panels are true golden rectangles, following the ratio 1:1.618 for aesthetically pleasing forms. Often attributed to Pythagoras, but formally termed the divine proportion in Luca Pacioli’s 1509 treatise Divina Proportione, the ratio has served as an inspiration for architects for centuries. In addition, Czajka formed his triangular glass trusses to echo the proportions and placement of the pediments over the academy’s first floor windows. The goal may have been to make the Glass Link disappear into the historic fabric, but instead it is a worthy enough addition to be a destination of its own.