Code: Conversion (Change to building use or units)
Description: (Building conversion – change of use or layout) is any change to the way a building or part of a building is used or divided, such as adding or removing dwelling units, changing rooms to apartments, or turning storage or commercial space into living space.
Practical Meaning: For a NYC homeowner, conversion usually means changing how many units your building has or how rooms are used, which almost always requires DOB permits and approvals. An illegal conversion is when you make these changes without proper approval, which can bring serious safety issues, fines, and orders to remove the extra units or work.
Where You May See It: You may see “conversion” or “illegal conversion” on DOB violation notices, inspection reports, HPD complaints, 311 complaint records, or zoning and planning discussions about changing a one‑family house into two or more units, or turning a basement, cellar, attic, or garage into an apartment.
Why It Matters: Conversions that do not match DOB permits or zoning rules can lead to large civil penalties, emergency vacate orders, problems with insurance coverage, and trouble when refinancing or selling the property. Understanding when a planned change counts as a conversion helps you know when to hire design professionals, apply for permits, and avoid creating an illegal unit.
Source: More About Illegal Conversions