Turning a retail space into a restaurant. Converting a warehouse to offices. Adding an apartment above a store, or turning a doctor's office back into a residence. Each of these is a change of use, and in New York City a change of use means the Certificate of Occupancy has to change with it. It is easy to underestimate, in both time and cost. Here is how it works.
What a Certificate of Occupancy is
A Certificate of Occupancy (CO) is the Department of Buildings' record of a building's legal use and occupancy: what each floor may be used for, how many people may occupy it, the number of dwelling units, and the occupancy classification under the Building Code. Buildings built after 1938 generally have one. Many older buildings do not, and their legal use is established by other records, such as an I-Card for multiple dwellings or the pre-1938 department records; the DOB borough office can also issue a Letter of No Objection to confirm it. Either way, the legal use is documented somewhere, and DOB will compare the proposed use to it.
A Temporary Certificate of Occupancy (TCO) allows occupancy for a limited period while outstanding items are finished; DOB says TCOs typically expire 90 days after issuance. A final CO is issued when everything on the job is complete and signed off.
When a change of use is triggered
A change of use is triggered whenever the actual use of a space will differ from what the CO or the legal record allows. Common examples: retail to food service, office to residential, residential to commercial, manufacturing to any other use, a change in the number of dwelling units, and any change in occupancy classification (for example from Mercantile to Assembly). Changes to egress, such as adding or removing an exit, also require a CO amendment even when the use stays the same.
Two things have to be checked before anything else. First, zoning: is the new use permitted in the zoning district under the Zoning Resolution's use groups, and does the building comply with the district's floor area, parking and other requirements for that use? Second, the Building Code: what does the new occupancy classification require in terms of egress, fire protection, accessibility and construction type? A use that is permitted by zoning may still be impractical under the code, and vice versa.
How the filing works
A change of use is filed in DOB NOW: Build as an alteration that requires a new or amended Certificate of Occupancy. The filing includes a new Schedule of Occupancy showing the proposed use of every floor, a zoning analysis (often with a ZD1 diagram), architectural drawings covering the code items below, and the standard forms for the work types involved. It goes through plan examination, and objections on change-of-use filings are common because the examiner is checking the whole building's compliance for the new occupancy, not just the renovated space.
What the design has to address
- Egress. Occupant load for the new use, number and width of exits, travel distance, door hardware, corridor and stair ratings. A restaurant has a higher occupant load than the retail space it replaces, and often needs a second exit.
- Fire protection. Sprinklers and fire alarm are frequently required when moving to an assembly use or increasing occupant load. Kitchen exhaust and suppression systems have their own filings.
- Accessibility. Chapter 11 of the Building Code applies to the altered space and often to the path of travel to it, including restrooms and entrances.
- Structural. A change in occupancy can change design live loads. The engineer has to confirm the existing structure supports the new use.
- Mechanical and plumbing. Ventilation, fixture counts and gas service change with the use, and each is a separate work type with its own licensed trade.
- Place of Assembly. Spaces where 75 or more people gather indoors, such as larger restaurants and bars, require a Place of Assembly Certificate of Operation in addition to the CO, with its own inspections and an FDNY permit.
- Other agencies. Landmarks approval if the building is designated, DOT for sidewalk cafes, DEP for grease interceptors, and the Department of Health for food service.
Inspections and the new CO
Once the work is complete, the job goes through final inspections: construction, plumbing, electrical, fire protection, elevator if applicable, and the special inspections on the TR1. The applicant submits the close-out documents, and DOB issues the amended or new Certificate of Occupancy. If a few non-life-safety items remain, a TCO can be requested to allow the business to open while they are finished. TCOs expire and have to be renewed, so the final CO is still the goal.
Common ways this goes wrong
One frequent mistake is treating the change of use as an afterthought to the interior fit-out: signing the lease, designing the space, and only then discovering that the use is not permitted by zoning, that a second exit is impossible, or that the building has no CO and the legal use has to be established first. Another is operating on an expired TCO. A zoning and code review before the lease is signed avoids the first, and a renewal date on the calendar avoids the second.
Plan ahead
Build the CO timeline into the lease negotiation and the construction schedule from the start, or have us map it for you. Our Sign-Offs & Certificate of Occupancy and DOB Filings services cover the path from the zoning check to the final CO.