THE DEVELOPER’S GUIDE TO MULTIFAMILY CONVERSIONS IN NEW YORK CITY

NYC’s conversion wave is moving fast. This guide gives developers, architects, and property owners a clear view of the zoning, code, and regulatory landscape and how to navigate it from feasibility through Certificate of Occupancy.

Why This Guide Matters

Converting a building in New York City is not simple, and the rules just changed significantly.

Across the city, teams are facing:

• Expanded eligibility under City of Yes Housing Opportunity, effective December 2024

• Complex light and air requirements that determine whether a project is viable at all

• Tax abatement deadlines that can mean millions of dollars in project economics

• Multi-agency approval processes involving DOB, HPD, and the Attorney General’s Office

This guide explains what’s changed and how to move forward with confidence.

What You’ll Learn

• Why conversions are on the rise. The market forces, vacancy pressures, and regulatory shifts driving NYC’s office-to-residential boom.

• How City of Yes changed the math. What the December 2024 zoning amendments mean for building eligibility across all five boroughs.

• The light and air question. Why floor plate depth is the first thing to assess and how experienced teams solve for it.

• Tax abatement programs that affect your pro forma. A breakdown of 467-m and 485-x, including the timing strategies that protect project economics.

• How to preserve grandfathered bulk. The demolition thresholds that determine whether your building stays as-is or must comply with current regulations.

• The full conversion process. From feasibility study through final Certificate of Occupancy, what happens, in what order, and where projects stall.

The Milrose Advantage

Milrose and JM Zoning support conversion projects across the entire regulatory lifecycle, from early feasibility through post-occupancy compliance. With more than 40 years in NYC’s permitting environment and the #1 permit filing volume in the city, our team knows how to move projects forward.