Manhattan’s West Side Highway is lined by a gleaming wall of glass and metal. The skyscrapers along this stretch tend to be tall and boxy—aside from one conspicuous exception. Forty Tenth Avenue, a 12-story building from Chicago architecture firm Studio Gang, cuts a jagged silhouette against an otherwise rectilinear skyline. The southeastern side of the building tapers back from the eighth floor toward the roof and narrow base, creating an hourglass-shaped carve in the facade (pictured). On the northeastern side, the building slants inward, with a diamond shape carved out. The unusual design is courtesy of Gang’s “solar carving” concept, which uses software to model the sun’s path through the sky throughout the year and allows the studio to shift, tuck, and slant a building to minimize the shadows it casts. “We think of it from the standpoint of, How would you shape or carve a building like a sculptural block to benefit its surroundings?” says founding principal Jeanne Gang. In the case of 40 Tenth, the goal was twofold: Open up views to the Hudson River for pedestrians and deliver more light to the High Line, a plant-filled, parklike walkway that snakes through the west side of Manhattan and is increasingly shadowed by surrounding buildings. Working with engineering firm Arup, Studio Gang analyzed a host of factors, including sun path, sight lines, and the position of nearby structures, to determine where 40 Tenth should be carved to deliver maximum sun exposure. The design works—pedestrians in the park have clear views of the river, and the High Line’s gardens soak up triple the sunlight hours they would have with a traditional building—proving that architecture can steal the spotlight and still be a considerate urban neighbor.
Mapping the sky
Studio Gang used parametric modeling to plot the sun’s changing path over the course of a year and combined that information with other factors, such as optimal sight lines and how much sunlight the High Line’s foliage requires. Architects then altered the shape and setback of the building to increase the number of solar hours that fall on the High Line from 351 to 1,164 per year (with the majority of those occurring during the prime growing seasons of spring and summer).
A great view
The building boasts two outdoor spaces: a plant-filled, 10,000-square-foot roof-deck overlooking the Hudson River and an 8,000-square-foot terrace on the second floor that has views of the High Line.
Shiny glass towers are bad for birds—and human eyes. Forty Tenth is clad in high-performance, low-reflectivity glass, which helps prevent birds from crashing into the building and reduces glare for drivers on the West Side Highway. The building’s faceted walls also create visual noise that helps birds steer clear.
Exposed, angled concrete beams support the building’s cantilevered sections while giving the interior an industrial-chic look. Most of the office floor plans include balconies that jut outward, supported by the building’s carved units.
Pedestrian park and gardens
The High Line was designed with light-loving prairie grasses and perennials like little bluestem and coneflower. The building’s placement and shape help the sun reach an additional 110 feet of the pedestrian park (and the flowers that line it).
New York City’s zoning regulations would have allowed 40 Tenth to cantilever over a portion of the High Line, but instead Studio Gang got permission to build the 145,000-square-foot tower taller and narrower—leaving enough space between it and the High Line for a terrace.
An optimized shape
The building has two unusual facades that allow sunlight to pass by it at inverse angles—an hourglass-shaped one (pictured) and a diamond shape on the opposing face. The diamond carve allows light to glance around the building, hitting the sundeck of the High Line. On the southeastern side, the hourglass carve ensures the sun reaches the base of the pedestrian walkway; a cutback at the top means fewer shadows for the rest of the neighborhood.
A version of this article appeared in the November 2019 issue of Fast Company magazine.