About Face: Giving Existing Towers a Modern Edge With Recladding
475 PARK AVENUE SOUTH, NEW YORK, NEW YORK
Project type: Curtain wall replacement
Architect: Pelli Clarke Pelli Architects, New York, New York
Architect of Record: The Spector Group
Curtain Wall Consultant: Israel Berger & Associates / Vidaris, Inc.
Curtain Wall Contractor: Permasteelisa
Owner: Charles Cohen
Photos courtesy of Pelli Clarke Pelli Architects
Before renovation on the left, After renovation in the middle and Glazing detail on the right.
This 35-story, 400,000-square-foot tower was built in 1969 according to the design of prominent New York architects Shreve, Lamb & Harmon Associates who were best known for designing the Empire State Building. Some 35 years later, the current owner was confronted with a combination of motivations for a new exterior recladding. First, the brick on the façade had started to show signs of failure, raising concerns that pieces might start falling and crashing to the ground below. Second, there was a need to upgrade the appearance in order to make the building more marketable to New York City tenants.
After going through a feasibility assessment, the first step was to remove the brick cladding and add some temporary waterproofing to the fully occupied building. This bought some time while the design team led by Pelli Clarke Pelli Architects (with The Spector Group as architect of record) explored a variety of glazed curtain wall design options. The analysis included a mix of clear and patterned glass with ceramic frit coatings in different designs. They also investigated how to work with the chamfered edges of the existing building in an effort to enhance the overall image of the building. After working through options and creating several full mock-ups, the final design uses six different frit patterns across the façade that complement clear vision glass panels in a striking, contemporary pattern. This provides visual interest and texture to the façade but also creates the appearance of different materials being used other than glass. Although the façade looks like it has metal panels crisscrossing it from afar, up close it is clear that the exterior is, in fact, entirely glass with different treatments. This re-clad design shows just how versatile glass can be since glazing technology now allows glass to mimic other materials. It has been noted that the designers have created a “modern interpretation of the trompe l'oeil.” While not using paint, the varied glass appearances result in a unique effect that offers visual interest and dynamism.
For the tallest portion of the building, the curtain wall system extends out past the chamfered corner, creating a more defined edge to the building and further enhancing the design transformation. Since the work occurred with the building fully occupied, and in order to avoid tenant disruptions, the removal and replacement of windows occurred on nights and weekends, allowing the interior work to be kept to a minimum. After that, a suspended scaffolding system was used to install the new curtain wall panels from the top of the building using new or existing anchorage components on the exterior. The full project, including a separate lobby upgrade, is scheduled to be completed by the end of 2015.
Images courtesy of Pelli Clarke Pelli Architects
The recladding of 475 Park Avenue South in New York City involved specific treatments for different parts of the building as shown.
Design Strategies
While the aforementioned three-phase process remains fundamentally the same across all façade renovation projects, there are five fundamental design strategies that can be considered.2 Each one has varying impacts on the existing building and are discussed further as follows:
Image courtesy of Enclos
Four common types of façade retrofit strategies are: 1) replacement, 2) recladding, 3) over-cladding, and 4) double skin. A hybrid approach that combines elements of any of these four is a valid fifth strategy.
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