One Madison Avenue

One Madison Avenue didn’t start as a blank lot. It started as a tired full-block office building from the 1950s, and the bet behind the project was that keeping most of it would beat tearing it down. The finished tower rises 27 stories over Madison Square Park with about 1.4 million square feet of Class A space, and it kept roughly two-thirds of the original structure underneath the new glass.

Project Scope

Developer SL Green, with partners Hines and Korea’s National Pension Service, hired Kohn Pedersen Fox to design the rebuild and AECOM Tishman to construct it. The team preserved about 67% of the existing 1950s frame, then added a slender tower expansion on top, a sequence that’s far harder to engineer than a clean-sheet high-rise. Loads from the new floors had to find their way down through a structure that wasn’t built for them. The result reads as a single contemporary building, with floor plates and systems tuned for tenants who can now lease space almost anywhere.

Why It Matters

Manhattan is full of mid-century office stock that’s too dated to lease and, increasingly, too carbon-expensive to justify demolishing. One Madison is a worked example of the alternative. Reusing the existing frame avoided a large slug of embodied carbon and shaved time off the schedule, while still delivering the kind of trophy floor plates that anchor tenants want. For owners staring at aging towers, it’s a template worth studying. Exchange has tracked the forces reshaping the office market, from construction spending trends to the towers redrawing the Manhattan skyline, and One Madison makes the case that the greenest new office building is sometimes the old one.

Project Team & Details