New York, NY, USA
Dan Kaplan, FAIA, LEED AP
Alchemy Properties (Developer)
David Sundberg Chris Cooper
Rising 347 feet above its site, its design establishes two distinct identities: one for Xavier High School, addressing the street realm, and one for the residential tower above, that addresses the sky. Anchoring the building, a stone-clad cubic base continues the scale of the block’s street wall. Careful modulation of fenestration and a “chiseled” design vocabulary equally accommodates the school’s functions and establishes the residential use’s identity. Poised above, the tower’s sloped, shard-like form and fish-scaled glass cladding reflect the sky, appearing to de-materialize the tower. The building’s sky exposure plane—a zoning restriction that traditionally limits design—is used here to sculpt a unique form that offers residents light, airy interior living spaces with unparalleled views of the surrounding cityscape. The building’s six-story base incorporates classrooms, a STEM lab, rehearsal space, and a double-height commons for the local non-profit institution Xavier High School. A mix of one-, two-, three-, and four-bedroom units occupy the top 18 floors, while a seventh floor amenity space includes a gym, lounge, children’s play room, shared wine cellar, and communal terrace. Constructed with flat-plate concrete, the tower provides ample footprints for apartments to allow for maximum planning flexibility. The building’s two principal uses are supported by completely independent MEP systems and vertical circulation infrastructure.
This unique, hybrid residential-educational building utilizes excess development rights from the adjacent Xavier High School campus, artfully provides needed expansion space for the school in its six-story base, and creates highly-crafted residential units that take advantage of their elevated location in a tower above. 35XV conforms to highly restrictive municipal massing controls, including sloped sky exposure planes, and is designed to be a “good neighbor” that relates to both the Xavier campus and to the streetscape of its dense neighborhood, despite the project’s overall size. By housing the addition to the school in its base, the development is positioned to support and improve the school’s role as a community anchor in exchange for using its air rights, allowing the building’s amount of residential floor area to increase by an additional 2/3 of its original limit. As a result of the agreement, 35XV’s innovative hybrid structure allows for large, long span spaces in the school’s portion of the building while a tower of 55 new condominiums cantilever over Xavier’s property (36 feet over the rear yard and 17 feet over the existing school building)—a superior model among the recent proliferation of cantilevered apartment buildings in Manhattan.
Certified LEED Silver, 35XV offers public value in private development through its partnership with Xavier High School and energy efficient design. Occupied since March 2016, 35XV is 100% sold and Xavier High School has moved its six-story campus in the building’s base. By pushing the building to the limits of the lot’s zoning envelope, it yielded a form that is at once hyper-rational in its maximization of the site’s land value potential, and also dramatic and easily recognizable in the cityscape and skyline. The angled profile façade translates on the interior to highly unique and differentiated living spaces, which substantially increase the value of 35XV’s residences, setting the bar for competitive comparable real estate data within the area. In terms of sustainable building practices, 35XV was designed to perform at an estimated 47% energy reduction compared to a median comparable property. Overall, more than 30% of materials used are made from recycled content, and more than 90% of construction waste was diverted from landfills. Furthermore, many materials qualify as low-emitting, contributing to a higher-than-average indoor air quality. With an emphasis on creating healthy environments, 35XV exemplifies easily attainable goals and best practices for mutually beneficial mixed-use, urban property developments, setting new standards in the growing trend of air rights development and setting a positive influence for future projects in the neighborhood and the city at large.