How Apartment Combining Contributes to the Housing Crunch

Most New York City co-ops and condos have at least one experience with a resident combining two (or more) apartments to create one much larger unit. Once the construction noise and dust settle, the outcome is usually happy: a shareholder has a big apartment, and values throughout the building are likely to enjoy a bump.

Now comes word that the recent frenzy of apartment combinations carries a high cost.

Through apartment combinations in co-ops and condos, as well as conversions of buildings with several units into single-family homes, the city has lost more than 100,000 apartments since 1950, according to a new analysis of building records shared with The New York Times. Overall, the number of apartments in the city has grown since then, but the pace of new construction has not kept up with the growth in population and demand.

The result: combining apartments is feeding the city's intractable shortage of affordable housing.

“I’m not trying to begrudge folks who are trying to build a larger apartment as their families grow,” says Adam Brodheim, a preservationist who did the research and is also a member of Open New York, a nonprofit that advocates for more development. “I’m trying to bring attention to the way these actions across the entire city make a meaningful impact on our housing crisis.”

He adds, “It’s not a problem if you were building a lot of new housing" — which the city is not doing.

The rate of combinations ramped up in the 1990s as the city came out of an economic crisis. They were clustered in wealthier neighborhoods like the Upper East Side and the West Village in Manhattan or Park Slope in Brooklyn, which housing experts say are the exact neighborhoods, with their easy access to transit and jobs, that should be adding many new homes.

The trend has continued since then — and spread into other neighborhoods when the city came out of the post-2008 recession and became increasingly wealthy. Today it is among the many reasons some neighborhoods have so little new housing — a troubling outcome when city officials have spoken in dire terms about the need to add housing to improve affordability and fight segregation.

Here's a telling case study: while 3,000 units of new housing were added in the community district that includes the Upper East Side between 2010 and 2021, about 2,000 units were lost through the consolidation of apartments, according to the research. Another 1,000 or so were lost in demolition.

End result: zero units of new housing, and a worsening housing shortage.