One Madison Avenue

With a design complementing its landmarked neighbor, the transformation of One Madison Avenue brings flexible, Class-A office space to Manhattan’s Flatiron District.

The design updates an existing, mid-century podium and adds an elegant new tower along with over an acre of outdoor space and multiple terraces, all boasting exceptional views of Madison Square Park and the adjacent 5 Madison Clock Tower. A new glazed opening with a series of green spaces visually connects the building to the park and extends it vertically through the tower, culminating in landscaped terraces on the upper floors.

At the podium, the limestone façade is retained and repaired, while aluminum windows and spandrels are replaced with a high-performance structurally-glazed curtainwall. Inside, the gut-renovation enables large, open floor plates to accommodate flexible workspace, with maximized ceiling heights and a modern, Class-A vertical transportation system and service core. The new tower, with a glass, curtainwall façade, optimized floor-to-floor heights, and virtually column-free floorplates, steps away from the landmarked clock tower to establish a dialogue between past and present.

By retaining 67% of the building’s original structure, a significant amount of embodied energy was reused. The redesign is forecast to result in an energy reduction of over 60% against the AIA 2030 Commitment baseline. The project is designed to comply today with the 2030 building emission targets determined by NYC’s Local Law 97, one of the first legislations of its kind in the world.


New York, NY, USA


SL Green, Hines


Adaptive Reuse, Office


121,000 m2 / 1,300,000 ft2


Costar Impact Award (2024)

Project Website
Watch the full Adaptive Reuse video, part of the KPF Review Spring 2023 issue, here.

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Project Type:Adaptive Reuse
Project Location:Americas