Custom-engineered entrance system merges two distinctive architectural treatments
With perpetual demand for upscale housing in New York City and limited real estate, developers push creative ways to use available space. Zoning regulations and density requirements limit building height and the number of occupants. Developers and architects have utilized unused air space above neighboring structures. Cantilevered designs maximize square footage by building wider, not taller. A prime example of this is the new 35XV tower in New York City’s Chelsea neighborhood.
Developed by New York City-based Alchemy Properties and designed by New York City-based FXFOWLE Architects, 35XV is a study in contrast. The 25-story, mixed-use development features school facilities on the first six floors and luxury apartments on the upper floors. After discovering that Xavier High School–one of the city’s top Jesuit educational institutions–had development rights to the unused air space in a lot across from its campus, Alchemy Properties purchased the rights to build residential units there in exchange for new school facilities.
FXFOWLE designed 35XV with two distinct architectural themes to meet the aesthetic and performance requirements of each identity. The bottom floors that house the classrooms and a half-court gym are clad in white granite, which pays homage to the surrounding 19th-century-style streetscape while providing a functional base for the school. It also reveals a predominantly cubical concept. Conversely, the top residential floors feature an angular cantilever design that simulates a glass obelisk reaching towards the sky. This breaks the rigidity of verticals across the New York City landscape and creates a unique, immediately recognizable landmark in the Flatiron District.
The cantilever concept was engineered to fulfill Alchemy Properties’ zoning strategy. Instead of building upwards, the architectural team creatively leveraged horizontal dimensions to extend the design beyond the standard grid and over existing structures, thus maximizing square footage. This was achieved by installing steel columns under the cantilever that connect back to the lower podium for support. To compensate for the substantial forward pressure generated by the cantilever’s unique form, the 12th floor is post-tensioned. The stone-and-glass tower’s two distinct themes-one of the street and one of the sky-are disjointed in theory; however, meticulous attention was placed on the entrance system to skillfully tie the two concepts together.
The entrance is seemingly carved into the building’s granite lower façade. This creates a sculptural design that mirrors the forms of the residential envelope in order to provide harmonious cohesion. Although only one story, it also gives the entrance a monumental, two-story scale that complements the grandeur of the rest of the tower.
Accentuating the sloped nature of the residential cantilever is an all-glass entrance system with multiple slants and planes. The design intent was for it to integrate into the surrounding angled granite and have it create depth by acting as an “invisible screen” that produced a seamless transition indoors. This was achieved by installing large, point-supported glass panels that are affixed through the granite using a stainless steel channel, and secured to the floor with a low-profile base shoe.
The focal point of the entrance is an all-glass, cubed vestibule that projects out of the glass wall-a sharp contrast to the skewed systems that surround it. The vestibule delivers scale and depth, and reflects the 90-degree planes of the school’s envelope. It serves as the final component to an entrance that merges two distinct architectural themes. According to Stephan Dallendorfer, principal at FXFOWLE and 35XV project director, the vestibule also, “Functions as a visual extension of the lobby, creating a red carpet arrival experience comparable to that of an upscale gallery space.”
It proved very challenging integrating an all-glass entrance-which typically exists as a linear glass front on a vertical plane-into an opening consisting of multiple angles. The granite cladding compounded the difficulty of securing heavy glass to the angled structural steel attachment points at the head. Maintaining an all-glass, asymmetrical aesthetic that embodied the cantilever’s design was essential, however. When asked to consider alternatives, Dallendorfer stood firm. “The entrance design is like a Swiss watch, every element is articulate and has a purpose,” he explains. “You can’t start peeling away the pieces because the design is only successful if you go all the way with the glass, hardware and details.”
To overcome these challenges, the team at FXFOWLE worked closely with Los Angeles-based CRL-U.S. Aluminum
(C.R. Laurence Co. Inc.)–who supplied the components of the all-glass entrance system including the base shoe, door rails, spider fittings, Blumcraft panic handles, and custom-fabricated metal canopy panels-and glazing contractor, Walsh Glass
& Metal Inc., Yonkers, N.Y. CRL-U.S. Aluminum’s drafting and design team utilized 3-D Autodesk Inventor modeling software to find a solution that would accommodate the complex geometry where the glass panels meet the granite. It then produced shop drawings that illustrated the connection details.
As the anticipated LEED Silver 35XV tower demonstrates, an innovative, collaborative approach can produce a grand entrance that effectively ties two aesthetic concepts together, making the overall design a success.
35XV, New York City
Developer: Alchemy Properties, New York City
Architect: FXFOWLE Architects, New York City
Glazing contractor: Walsh Glass
& Metal Inc., Yonkers, N.Y.
All-glass entrance system: CRL-U.S. Aluminum (C.R. Laurence Co. Inc.), Los Angeles, www.crl-arch.com
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Andrew Haring is the vice president of marketing at Los Angeles-based CRL-U.S. Aluminum (C.R. Laurence Co. Inc.) To learn more, visit www.crl-arch.com.