New York City’s official chronicler on Fifth Avenue and 103rd Street was originally designed in 1929 as a grand mansion suitable for its subject matter.

Image: Polshek Partnership Architects
At $80 million and covering three phases, the renovation and expansion of the museum will see the reworking of 90,000 sq ft and the addition of 23,000 sq ft of space.

The city’s wealthiest residents funded the construction of the five-story Museum of the City of New York in Georgian Revival style, with a grand entrance facing the world’s most famous city park. Mayor James Walker laid the cornerstone for the new building, thus creating, with the Metropolitan Museum of Art at the other end, what became known as Museum Mile.

And then, as new museums popped up in between and the city went through some of its worst economic times, the museum was quietly forgotten. Half a century later, it badly needed repairs.

In the 1980s, New York’s Polshek Partnership Architects proposed a master plan for a massive expansion and an upgrade of the building’s interiors, and Marlton, N.J.-based Hill International was selected as the construction manager. But plans changed, and the work was put on hold.

It wasn’t until 2006, under a powerful mayor, that the museum’s first substantial renovation since the ’30s began.

“Since I started working on this project, I’ve gotten married, had two kids, and the first one just had his graduation from college,” says Timothy Hartung, Polshek’s project manager, laughing quietly.

While the original ’80s plans called for a significantly larger expansion, the current $80 million, three-phase work is no less ambitious in scope. And, all the work on 90,000 sq ft of renovation and a 23,000-sq-ft expansion is happening while the museum stays open for staff and visitors.

The $22 million phase one of the project, completed last year, included renovation of the Fifth Avenue entrance and its entry court, which was previously covered in shrubbery and is now a programmable space that is frequently rented out for functions separate from the museum.

Inside, the team restored the lobby, adding a storefront and new openings, but leaving intact and restoring a grandiose marble spiral staircase.

“I don’t think we could have rebuilt one of these,” says Michael Brothers, the project executive with Hill. Hartung adds that the staircase “is one of the most sought-after post-marriage ceremony spots in the city.”

Testing for structural integrity as it went along, the team did make an opening underneath the stairwell, to connect the lobby to phase one’s most outstanding feature: a 23,000-sq-ft addition that includes the museum’s first climate-controlled gallery as well as, in its basement, a climate-controlled storage center, complete with a vault, for the museum’s rarest and most fragile pieces.

The new wing was finished just in time for this year’s 400th anniversary of Henry Hudson’s discovery of the region, and now houses a model replica of his ship Half Moon. There is also an extensive collection of manuscripts and artifacts from the era, in a comprehensive program coordinated with the government of the Netherlands (Hudson’s employer).

The exhibit has the feel of a tasteful archeological presentation, with dim lights reflecting off of wood floors and additional lamps highlighting the collection’s pieces.

But a museum that prides itself on covering not just what was, but what is—such as hip hop’s influence on fashion, to name one recent exhibit—still needs more versatility and an update to the aesthetics of the 21st Century. Polshek Partners had previously integrated such aesthetics into its projects, at the Rose Center at the Museum of Natural History and the new foyer at the Brooklyn Museum, and so it was keenly aware of what was needed at the museum.

The new building is glass.