The steeply-pitched mansard roof of 150 Central Park South, an iconic copper patinaed topper that stands out among its West 57th Street neighbors, will eventually be home to more than storage and HVAC equipment. SPAN Architecture is converting the previously-unused roof floors into a triplex condo unit with surround-views of Central Park, and AN got to tour the raw space before construction begins.

150 Central Park South, also known as Hampshire House, was completed in 1937 after six years of delays caused by the Great Depression. The 37-story, limestone-clad building is instantly recognizable owing to a cascading series of terraces on the northern face, and the two chimneys that bookend its massive copper top. Despite its age and famous tenants, the tower isn’t a landmarked building, allowing for significant interior alterations with the permission of the co-op board and Department of Buildings (DOB).

Among them? Two floors could be added, punching 40-foot-tall windows into the roof (after a restoration), and a terrace could be built on the Central Park-facing side.

According to SPAN principal Peter Pelsinski, the “eureka” moment came during a survey for the (then) top-floor apartment on the 37th floor. Questioning where the mechanical systems were held, SPAN discovered that the space inside of the roof directly above—also used as storage—could be converted into two new floors with 14-foot-tall ceilings.

Photo of the Hampshire House penthouse at 150 Central Park South

The current, raw interior of the roof tapers to a steep interior point. (Jonathan Hilburg/AN)

A tour of the current space revealed ample exposed terra-cotta block insulation (commonly used for fireproofing in older buildings), anchors connecting the copper cladding to the raw concrete walls inside, and a soaring vaulted ceiling reminiscent of a cathedral.

With so much height to work with, SPAN ran through over 15 different schemes before arriving at their current layout, though it was also noted that any potential buyers would have the ability to customize the triplex. Some of the wilder schemes for the 39th floor involved leaving it out entirely and opening up the full height of the ceiling, running a pool from one end of the building to the other, or turning it into a gym, an office, or a full cinema.

Photo of view from the Hampshire House penthouse at 150 Central Park South

The current view from what will become the 39th-floor terrace. (Jonathan Hilburg/AN)

The current plan as approved by the DOB would see the renovation of the current 1,100-square-foot 39th-floor unit, the addition of living rooms on both the 38th and 39th floors, a bedroom and bathroom at each end of the 38th floor, a family room, and a full kitchen and dining room. The nearly-floor-to-ceiling windows in the top-floor living room will also have the ability to open up to the 39th-floor terrace facing the park and create a seamless indoor-outdoor space. When fully built out, the triplex will hold 8,585 square feet of interior space and 1,225 square feet of accessible outdoor space.

SPAN went with a neutral palette for the interior, in part as a response to the colorful backdrop that Central Park presents. As the seasons change, so does the color of the foliage, and with so much of the penthouse’s view oriented towards the park, the firm didn’t want to lock themselves into a color or material scheme that would only sync up some of the time. With white walls, herringbone floors in light wood (already found in the 37th-floor unit), and white marble in the bathroom, the aim was to enhance, not detract from, the view.

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