New York City is home to many of the most iconic buildings in the world. The familiar skyline is displayed on various postcards and photographs and is often referenced in pop culture each day. In addition to being known for its diverse cultures and high-end fashion, the Big Apple is home to many skyscrapers, including One World Trade Center, the Empire State Building, the Chrysler Building, and of course, the Flatiron Building. Originally designed by Daniel Burnham and completed in 1902, the Flatiron Building sits at 175 Fifth Avenue in the heart of its namesake, the Flatiron District. The structure was one of the earliest skyscrapers in New York City history and quickly became one of its top tourist attractions, mainly due to its unique triangular shape. In 1966, the Flatiron Building was designated as a landmark in New York City and would become a National Historic Landmark in 1989. The Flatiron Building was originally developed as offices for the Fuller Company and remained as such until 2019 when Macmillan Publishers left the building.
In 2023, a revamped ownership team agreed to convert the tower into residential condominiums. GMS had provided structural engineering to the ownership team in the building for several years and our building envelope team was added for this new chapter.
The building includes 140,000 GSF of residential space, 16,350 GSF of lobby and retail space, and 10,000 GSF of amenity space. The residential program consists of about 38 units, with two units on each floor and a penthouse suite on the 23rd floor. The amenities will include a swimming pool, locker rooms, a sport court, a lounge/screening area, owner storage, and a fitness center. GMS designed new framing and reinforcement of the existing steel structure for the many proposed changes and upgrades to the building. Most of the work centered on the reconfigured building core with new egress stairs, a service elevator and two new passenger elevators serving the north or south units. We also performed structural analysis to assess the impact of the new core on the existing lateral load resisting system. Locally, we evaluated the original terracotta tile arch floors for the proposed MEP systems including risers for the new residential units.
One of the most challenging aspects of this project has been its landmark status, which protects its historical and cultural value. This made it particularly demanding for our building envelope group, as all upgrades had to be carefully designed to preserve the building’s exterior appearance. Our building envelope team was involved in the replacement of the existing windows throughout the building. The original windows were double-hung and did not perform well from an energy standpoint, so the new windows were designed to be operable while closely replicating the originals in terms of color, material, and depth, ensuring that the change is not noticeable from the exterior. A significant portion of the work has taken place at the upper levels, particularly at the terraces and penthouse. We provided new roofing, waterproofing, railings, and a new brick enclosure at the penthouse level, replacing the original stucco exterior. At the lower levels, we provided foundation waterproofing for a new pool, along with the replacement and waterproofing of the existing sidewalk.
As work on the project is continuing to progress, some residences were listed for sale earlier this year. With its rich history and landmark status, the redevelopment of the Flatiron Building is undoubtedly one of the most special projects we have ever worked on in our firm’s history. To see more about our work, kindly visit our website at www.gmsllp.com.