In 2016, CHPC launched its Hidden Housing study to investigate the scope of opportunity that exists for the conversion of basements in New York City into safe and legal rental apartments. At a time when new housing is urgently needed, Hidden Housing found that there are between 10,000 and 38,000 potential apartments that could be brought into safe and legal use in New York City without changing the Zoning Resolution.

These thousands of potential apartments are in the basements of existing small homes, making them unusually advantageous. Basement conversions bring rental units to the market without having to acquire land. They add apartments without altering the size or shape of the building. They inherently rent for less than similar, above-grade apartments. Homeowners can pay a mortgage, maintain their property, or pay other household expenses with the rent earned on the secondary unit. Basement apartments offer housing options to under-served groups, like extended families and new immigrants.

Based on the study findings, CHPC believes that a basement conversion pilot program in New York City would be an efficient and exciting way to add residential density and expand housing choices in our expensive and highly constrained urban market. It would also address the urgent health and safety concerns connected with illegal occupancy, which occurs far too frequently because the demand for housing is so high.

In the Hidden Housing report, CHPC makes the case for basement apartments in New York City and provides six key recommendations for how a basement conversion program could be implemented:


1) Identify the most suitable geographic areas for a pilot;
2) Offer homeowners some relief from parts of building regulations that are the most difficult to comply with when legalizing a basement apartment;
3) Cultivate more affordable fire suppression and prevention technologies that could be tested in the pilot project;
4) Commission and fund community-based organizations to support homeowners through the process;
5) Train and accredit architects and contractors who can appropriately undertake basement conversions;
6) Develop financial incentives so that homeowners can afford the required work, be protected against tax increases, and be encouraged to keep rents low.

Click HERE to download and read the report!


Special thanks to our project funders who continue to be essential partners in this
Capital One
Deutsche Bank
The Charles H. Revson Foundation