New York City Mayor Zohran Mamdani’s attempt to revive an old plan to build 12,000 affordable units over a borough railyard is seen as a long shot, even if he gains support from President Trump.
Mamdani has garnered headline attention for proposing to build units on a platform above Sunnyside Yard, a 180-acre freight and marshaling area in Queens. The ambitious idea has been stuck in neutral for more than a decade.
However, real progress on housing affordability in one of the world’s most expensive cities might be more gradual and effective than focusing on a single large, costly, publicly funded project.
Like many cities across the country, New York City officials have struggled with local zoning laws as they push to simplify the construction of housing.
In November, voters approved four amendments to the city’s charter related to affordable housing. They also elected Mamdani partly because he promised to speed up planning reviews for affordable projects.
Mamdani already has a December 2024 citywide rezoning ordinance titled “City of Yes for Housing Opportunity” at his disposal. City officials stated that this rezoning could potentially add 80,000 new homes over the next 15 years.
The changes made it easier to convert office buildings into residences. The ordinance also laid the groundwork for reviving shared housing, but it still requires other updates to building, fire and maintenance codes.
The city leads the nation in office-to-residential conversions. In his final month in office in December, former Mayor Eric Adams said more than 12,000 units are already in the pipeline, with additional projects announced this year.
Apartment units sitting empty
New York City still has a long way to go to address a roughly 1.4% apartment vacancy rate. That rate does not include empty rent-stabilized units, which some estimates suggest could be as high as 100,000.
Landlords intentionally keep apartments vacant because they can’t increase rents enough to cover renovation expenses for new tenants.
A 2019 state law closed a loophole that previously allowed landlords to remove apartments from rent stabilization when making substantial renovations.
Construction costs surged during the COVID-19 pandemic and haven’t decreased much since. That change in costs altered the financial calculations for landlords who own rent-stabilized units.
A favorable ruling in a federal lawsuit filed by multiple landlords could open up some of those vacant units. The lawsuit claims that the part of the 2019 law that closed the loophole is unconstitutional.
Making early incremental progress
Until the city figures out what to do about vacant, unrented units, it is making little progress on new housing.
The city’s new Expedited Land Use Review Procedure – created by one of the charter amendments – has its first project underway. The proposal aims to add 84 income-restricted units on city-owned land in the Bronx. The review is required to take 90 days by law.
Mamdani’s office states that this reduces the review process by about seven months. Construction on the Powerhouse Apartments is expected to begin in 2028.
A pending New York City Council ordinance would permit converting office buildings into single-room occupancy housing, both in existing structures and new Class A apartment buildings. The ordinance has the administration’s backing.
“Reintroducing purpose-built shared housing models provides a new set of tools to expand housing opportunity and choice to the growing population of single New Yorkers,” Michael Sandler, an assistant commissioner with the city’s Housing Preservation and Development Department, said in a December City Council committee hearing.
Sandler said the ordinance would establish clear rules for designing, occupying and maintaining safe shared housing. His department published a shared housing roadmap in November.
Converting obsolete offices to residential
New York developer RXR Realty secured a $420 million loan to transform a Financial District office building into nearly 800 apartments, with 25 percent designated as affordable. The developer is leveraging a tax abatement introduced by state lawmakers in 2024 for projects that include a quarter of new units as affordable.
Bushburg, also a New York developer, recently acquired a 1970s office building in the Financial District and is transforming it into 400 apartments, with 100 designated as affordable. The developer obtained a $78 million loan from Oak Funding and OakNorth Bank.
“We felt confident that the city needs housing and needs affordable housing,” Jeremy Levart, co-founder and principal of Oak Funding, told The Builder’s Daily.
Going big sounds swell, but may be folly
Mamdani is bringing back a plan that originally appeared over 10 years ago under Mayor Bill de Blasio. It lost momentum in 2020 when the pandemic started.
The idea might struggle again, even if Mamdani persuades President Trump to back it. The funding could become an issue.
The estimated cost in 2020 was $21 billion and would need significant federal assistance. The late architect Robert A.M. Stern, known for designing notable condominium and apartment towers, told the New York Post in 2015 that this approach was naïve.
“It’s just so expensive,” he said.
Experts say the all-affordable, union-labor mandate is unsustainable without large subsidies. Building over an active railyard also creates significant engineering challenges and bureaucratic hurdles.
Focusing on the basic tasks of smaller projects that require less public funding might be Mamdani’s best chance for significant progress.