Legal Use Of A Building In NYC

by | Last updated Jun 4, 2020 | NYC DOB, Property Development

All buildings in NYC must comply with regulations of use and occupancy. When dealing with existing buildings one must determine the legal use of a building before making any alterations.


Building Legal Use NYC

Verifying The Legal Use Of A Building

  • Certificate Of Occupancy
  • HPD Online
  • I Card
  • Letter Of No Objection – LNO
  • Department Of Buildings DOB Records / Microfilm


Certificate Of Occupancy

A Certificate Of Occupancy (CO) (CofO) is a document issued by the Department Of Buildings indicating the legal use and occupancy of a building. Not all buildings have a Certificate Of Occupancy but if the use of a building will change the owner must acquire a new or amended CO.

It is important to determine the legal use of a building in order to know if you will require a new Certificate Of Occupancy. In order to get a new, or amend an existing, Certificate Of Occupancy you must file an Alteration Type 1 or Alt 1 with the DOB. If your legal use will stay the same and you are renovating the space you can file the less complicated Alteration Type 2 application. Determining the existing the legal use will be essential in deciding to file an Alt 1 vs Alt 2 application.

To find your Certificate Of Occupancy you can look your building address up on the DOB BIS (Building Information System).

Changes to use, occupancy, and egress will require a new or amended certificate of occupancy and an Alteration Type 1 filing. If you completely demolish a building you will file an NB application for your New Building.


Buildings Without a Certificate Of Occupancy

Not all buildings have a Certificate Of Occupancy. The certificate of occupancy has only existed since 1938 and there has been no requirement for applying to get a new one if the building maintains its original use.


Housing Preservation & Development HPD Online

HPD has a very simple to use property lookup tool called HPD Online. This will be a good starting point for determining a building’s legal use. If the building is a residential building HPD will list the number of legal apartments and the type of apartments.

HPD has 2 types of apartments:

Class A Units – Class A apartments are normal apartments a private apartment with a kitchen and at least one full bathroom with living space / bedrooms.

Class B Units – A class B apartment is an SRO or Single Room Occupancy. Converting an SRO will require a new Certificate Of Occupancy.


HPD I card

HPD online also has I Cards. An I card is an old hand written document outlining the use off a building and potentially with diagrams or plans of the building. Not all buildings are going to have an I card but they are scanned and can be found online. a simple warning sometimes they are not easy to read.


Letter Of No Objection

A Letter Of No Objection or LNO is a document with the Department Of Buildings that can be used for properties without a Certificate Of Occupancy. You can submit an LNO application to the DOB for your proposed use on a building and they will either approve it or issue an LNO to state they have no objection to the proposed use. If you get an LNO for a particular use when renovating you will not need to file an Alt 1 you can file the simpler Alt 2 application.


Department Of Buildings DOB Records / Microfilm

The Department Of Buildings may have microfilm of the original plans and or paperwork of a building. This is hot or miss sometimes you find a full set of drawings sometimes you find nothing. They may even find an old job folder with the actual original blue prints for the building. If they do find the original documents or plans you can use those to verify the Legal Use Of  a Building.


Thank You for Reading our Blog Post on NYC Property Data Lookup.

Please leave questions or comments below. If you want to discuss a specific property you can contact us directly.


Contact Fontan Architecture


Jorge Fontan
Jorge Fontan

This post was written by Jorge Fontan AIA a Registered Architect and owner of New York City architecture firm Fontan Architecture. Jorge Fontan has earned 3 degrees in the study of architecture including two degrees from the City University of New York and a Masters Degree in Advanced Architectural Design from Columbia University. Jorge has a background in construction and has been practicing architecture for 20 years where he has designed renovations and new developments of various building types.