NYC Building Permits

by | Last updated Jun 4, 2020 | New York City, NYC DOB

There are different types of NYC Building Permits. A construction or building permit must be acquired before you begin any construction project in NYC including new buildings and renovations or alterations. In NYC building permit applications must be filed by an R.A. Registered Architect or P.E. Professional Engineer.


Types Of NYC Building Permits


  • NB – New Building Permit
  • Alt 1 – Alteration Type 1
  • Alt 2 – Alteration Type 2
  • Alt 3 – Alteration Type 3
  • Demo – Demolition Permit


NB New Building Permit

Filing a new building application with DOB is filed as an NB. An NB is one of the NYC building permits. NB stands for New Building. Any new construction in NYC will require an NB permit. This is defined by building a new building without keeping any portion of an existing building.

NB Permits and Applications are required for any type of new building construction this includes residential, commercial, and manufacturing buildings. Building a new houses in NYC also requires an NB application.

Example of projects that require NB NYC Building Permits and Applications:

  • New Houses
  • New Multifamily Buildings
  • New Commercial Buildings 
  • New Manufacturing Buildings
  • New Mixed Use Buildings


Alt 1 Alteration Type 1 Construction Permit

An Alt 1 or Alteration Type 1 is an NYC building permit for major renovations that require a change in use, occupancy, or egress. Some Alt 1s will fall into the category of a “Big Alt” and must follow the requirements for a New Building. Alt 1s that follow New Building requirements are still filed as Alt 1s. when you file an Alt 1 you will receive a new Certificate Of Occupancy after the work is completed, inspected, and signed off.

You can only have One Alt 1 open at a time on a building. all work must be complete and you must get a new Certificate Of Occupancy before you can file another Alt 1.

People often are uncertain about when to file an Alt 1 or Alt 2. We have a more detailed article you can read on Alt 1 vs Alt 2 applications.

Examples Of Projects That Will Need To Be Filed as an Alt 1:

  • Changing the Number of Apartments in a building
  • Changing a building use or portion of a building use
    • Converting Residential to Commercial
    • Converting one Commercial use to a different commercial use
    • Adaptive Reuse Projects
  • Major Interior Renovations
    • Any change that requires a new Certificate Of Occupancy
    • Changes that would contradict the existing certificate of occupancy
    • Changes that alter the means of egress to a building
  • Building Additions 
    • Adding floors on top of a building


Alt 2 Alteration Type 2 Construction Permit

An Alt 2 or Alteration Type 2 construction permit is for work that does not require an alt one. This is very common for interior renovations or exterior repairs and restoration. These applications will not require a new certificate of occupancy or a change to the means of egress. When an alt 2 is complete the original Certificate Of Occupancy (CO or C of O) will still be valid. If you do not have a CO for the building you can get a Letter Of No Objection to verify an Alt 2 is acceptable. You Should also verify the existing legal use and occupancy of the building.

Examples Of Projects That Will Need To Be Filed as an Alt 2:

  • Most Interior renovations
    • Gut Renovations can often be an alt 2
  • Apartment Renovations
  • Removing Walls and Building walls
  • Restaurant Renovations 
    • With no change in occupancy or use
  • Retail Renovations
    • With no change in occupancy or use
  • Office Renovations
    • With no change in occupancy or use
  • Building Restoration
  • Converting To Energy Efficient Buildings
  • Fire Damage Repair, Water or Flood Damage Repair


Alt 3 Alteration Type 3 Construction Permit

An Alt 3 or Alteration type 3 is a permit for minor alterations. These can only have 1 work type and must include only minor work. We rarely file alt 3s and when we do they are usually in conjunction with another building permit application.

Examples Of Projects That Will Need To Be Filed as an Alt 3:

  • Curb Cut
  • Construction Fence


Thank You for reading our blog post on NYC Building Permits / construction Permits

We wish you the best of luck with your building permit application. Please feel free to leave questions or comments below. If you want to discuss applying for NYC Building Permits with an architect 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.