Conversions Eliminated Over 100K Housing Units in New York City

Apartment-to-house conversions are contributing to a net loss of housing in some of the city’s historic neighborhoods.

1 minute read

August 28, 2023, 5:00 AM PDT

By Diana Ionescu @aworkoffiction


Colorful historic brownstones in New York City

goodmanphoto / Adobe Stock

According to an article by Rachel Holliday Smith in The City, “over the last 70-plus years, mergers of flats and rooming houses into bigger residences have taken a steady toll on [New York City’s] housing stock, a new study finds.”

The study from historic preservationist Adam Brodheim found that in Manhattan, where conversions have been most aggressive, “each conversion accounted for the loss of between six or seven units on average.” Based on Brodheim’s estimate, the city lost 104,000 housing units to conversions since the 1950s.

“In the past decade, such apartment combinations have nearly erased gains made by the construction of new housing units in the wealthiest parts of the city, particularly in the Upper East and Upper West sides of Manhattan.” The city’s historic districts also experienced a net loss of housing between 2010 and 2022.

The answer, for Brodheim and others, is not to limit conversions, but to make up for them.“Trying to restrict that activity is not necessarily beneficial because there is a demand for it. What this illustrates is that you just have to build a lot more housing.” 

Thursday, August 24, 2023 in The City

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Get top-rated, practical training

Wastewater pouring out from a pipe.

Alabama: Trump Terminates Settlements for Black Communities Harmed By Raw Sewage

Trump deemed the landmark civil rights agreement “illegal DEI and environmental justice policy.”

April 13, 2025 - Inside Climate News

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

April 23, 2025 - Diana Ionescu

Black and white photos of camp made up of small 'earthquake shacks' in Dolores Park in 1906 after the San Francisco earthquake.

The 120 Year Old Tiny Home Villages That Sheltered San Francisco’s Earthquake Refugees

More than a century ago, San Francisco mobilized to house thousands of residents displaced by the 1906 earthquake. Could their strategy offer a model for the present?

April 15, 2025 - Charles F. Bloszies

Looking out at trees on 4th Street in downtown Los Angeles, California.

LA’s Tree Emergency Goes Beyond Vandalism

After a vandal destroyed dozens of downtown LA trees, Mayor Karen Bass vowed to replace them. Days later, she slashed the city’s tree budget.

April 23 - Torched

White and blue Sacramento regional transit bus with one bike on front bike rack.

Sacramento Leads Nation With Bus-Mounted Bike Lane Enforcement Cameras

The city is the first to use its bus-mounted traffic enforcement system to cite drivers who park or drive in bike lanes.

April 23 - Streetsblog California

View of downtown Seattle with Space Needle and mountains in background

Seattle Voters Approve Social Housing Referendum

Voters approved a corporate tax to fund the city’s housing authority despite an opposition campaign funded by Amazon and Microsoft.

April 23 - Next City