23. January 2017
One element of New York City's famous Zoning Resolusion is the "sky exposure plane," a virtual sloping plane that determines the extents of upper floors in tall buildings to ensure light and air reach street level. This has resulted in the city's recognizable setback towers, but every now and then a building takes a more creative approach to the plane. FXFOWLE's design for 35XV, a residential and educational building at 35 West 15th Street in Manhattan, makes this aspect of the resolution physical by angling back the top fourteen floors. The architects answered a few questions about this striking addition to the Chelsea neighborhood.
What were the circumstances of receiving the commission for this project?
Alchemy Properties and FXFOWLE previously worked together on a condominium building on West 15th Street, directly across from 35XV. During this project, the team grew familiar with the block’s historic architecture, as well as the local community, including neighboring Xavier High School. In 2010, Alchemy purchased the property for 35XV as well as the high school’s unused development rights, with a vision to capitalize on the open space above the school’s low-rise campus.
Please provide an overview of the project.
A rare mid-block design opportunity engendered the creation of this unique Manhattan mid-rise. Employing dramatic cantilevers and an expressive, textured façade, 35XV exemplifies a truly unprecedented environment for both living and learning.
Rising 330 feet above 15th Street in Manhattan, 35XV is a unique, hybrid residential-educational building located in a commercially-mixed, historic neighborhood. The tower rises from a granite-clad base – an expansion of the adjacent Xavier High School – that extrudes the scale and materiality of the street-level context upwards for the first six stories of the building. A sculptural, angled glass form emerges above the base, providing a dynamic transition to a carefully sculpted, 19-story volume of high-end residences.
What are the main ideas and inspirations influencing the design of the building?
The zoning requirements for the tower’s location became the greatest design challenge for 35XV. The project resolves a complex three-dimensional puzzle that cleverly finesses the zoning, mix of uses, and unique attributes of this mid-block site. The design further leverages requirements that stipulate an angled sky exposure plane – traditionally a design constraint – to form a unique, angled structure with unparalleled views of the surrounding cityscape.
- Creating two identities: one of the street/city; and one of the sky - a stone-clad cubic base responds to and continues the scale of and materiality of the “street wall” while the tower’s sloped form and “fish-scaled” glass cladding serve to reflect the changing sky and dematerialize the tower
- Leveraging the sky exposure plane, traditionally a design constraint, to form a dynamic and iconic structure with unparalleled views of the surrounding cityscape and unique interior living spaces
- Hybridizing structural system with a steel frame at the base to accommodate the school program and maximized cantilevers to enable an ample footprint of the tower for large, gracious residences while flat rate concrete was incorporated in the tower floors for flexibility of planning
- Modulating of fenestration at base that accommodates equally the school functions and the residential identity.
How does the design respond to the unique qualities of the site?
The building design establishes two distinct identities: one for the 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. The building’s sky exposure plane – a zoning bulk 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 planning of 35XV employed an inventive use of air rights obtained from Xavier High School, which occupies an adjacent site on the north side of the property. In exchange for allowing the new condominiums to cantilever 36 feet over Xavier’s property, increasing residential floor area by 40%, the developer agreed to include a new education building at the tower’s base, allowing the school to expand its physical facilities on an otherwise tight, urban site.
Was the project influenced by any trends in energy-conservation, construction, or design?
35XV’s final design features a unique, sloped curtain wall façade with a complex shading system complimenting it on the interior. To overcome the myriad structural requirements, a hybrid support system was ultimately chosen by the client, with a steel frame at the base that accommodates the school and allows for extensive cantilevers in the tower portion above. The residential portion of the building is constructed with flat-plate concrete to provide an ample footprint for residences, and to allow for maximum flexibility of planning. Finally, a careful modulation of fenestration on the building’s educational portion equally accommodates the school’s functions and the building’s residential identity.
35XV was designed to perform at an estimated 47% energy reduction compared to a median comparable property. Overall, more than 30% of the materials used in the building are made from recycled content, and more than 90% of the project’s construction waste was diverted from landfills. 35XV also sets new standards in the growing trend of air rights development, meeting housing demands in a dense Manhattan neighborhood while providing needed support for a local non-profit institution, all within a contextually specific, dynamic design.
What products or materials have contributed to the success of the completed building?
38.23% of all architectural building materials were extracted or manufactured within 500 miles of the project site. The project used low-emitting, wet-applied products that were low in VOCs and free of added urea formaldehyde.
Email interview conducted by John Hill.
Ground floor plan
Typical residential floor plan
New York, NY
New York, NY
Dagher Engineering, PLLC
Beyer Belinder Belle (school)
BNO Design (residential)
AGA 15th Street LLC
Van Deusen & Associates
Cerami & Associates
Façade Maintenance Consultant
Entek Engineering, PLLC
7,744 square feet
170,000 square feet
David Sundberg/Esto, Chris Cooper