Theses Master's

Bigger Houses, Fewer Homes: Dwelling Unit Consolidation in New York City

Brodheim, Adam Oscar

Dwelling unit consolidation, whereby two or more housing units are combined, is an under-studied aspect of housing in New York City. While previous research has identified the practice historically, particularly in relation to “brownstoning” and early gentrification in New York City, the full historical and modern extent of the practice has not been studied or quantified. Over the past 70 years, over 50,000 small multi-family buildings have been converted to one or two-families, resulting in a loss of approximately 100,000 units of housing. Concurrently, many larger multi-unit apartment buildings have seen decreases in their overall number of units, as adjacent apartments are combined.

This study uses archival building records and contemporary building permits to identify cases of dwelling unit consolidation in New York City. Geospatial methods are employed to identify clusters of the practice, quantify the overall impact, and describe the demographic characteristics of areas where the activity is most common. It shows that dwelling unit consolidation disproportionately occurs in historic districts (both historically and currently), and that the activity primarily occurs in census blocks that are whiter and wealthier than the surrounding neighborhood. It concludes with a discussion of policy responses to dwelling unit consolidation in other cities. Ultimately, this thesis finds that dwelling unit consolidation is an “unintended consequence” of historic preservation, and that policy makers must actively engage with such negative externalities to historic preservation going forward.

Geographic Areas


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More About This Work

Academic Units
Historic Preservation
Thesis Advisors
Clark, Carol A.
M.S., Columbia University
Published Here
June 21, 2023