What Is an Alt-2 Application? NYC Building Permits

Alt-2 Application: A New York City Department of Buildings permit application type for alterations to existing buildings that do not change the occupancy classification or use group, including structural alterations, plumbing, electrical, and mechanical work that requires professional review.

NYC's Unique Permit System

New York City has its own building permit system that differs significantly from other U.S. cities. Rather than a single "building permit," NYC uses numbered application types based on the nature of the work. Understanding which application type applies to your project is the first step in the NYC permit process.

Alt-1, Alt-2, and Alt-3 Compared

Alt-1 (Full Alteration): Required for alterations that change occupancy or use, or for major alterations requiring a new or amended Certificate of Occupancy.

Alt-2 (Partial Alteration): Required for alterations that do not change occupancy and do not require a new CO. Covers most significant residential renovations: structural changes, bathroom or kitchen remodels involving plumbing, electrical upgrades, and window modifications. Must be filed by a licensed architect or engineer.

Alt-3 (Minor Alteration): For minor work not requiring professional certification — covered under a simpler self-certification process.

Who Can File an Alt-2

Alt-2 applications must be filed by a licensed architect or engineer registered with the NYC DOB. The filing professional certifies that the proposed work complies with applicable codes. Property owners cannot file Alt-2 applications themselves — the licensed professional is legally responsible for the filing's accuracy.

The Alt-2 Process

The Alt-2 process involves plan filing through the DOB NOW system, plan examination (either by DOB examiners or through the Professional Certification program, where the filing architect self-certifies), permit issuance, construction, and inspections. The Professional Certification route significantly speeds up Alt-2 approvals in NYC — experienced architects can often file and receive approval within days rather than weeks.

Frequently Asked Questions

Yes, if the renovation involves plumbing changes or structural work, an Alt-2 must be filed by a licensed architect or engineer. Simple cosmetic work (tile, fixtures in the same location) may not require an Alt-2. When in doubt, consult a DOB-experienced architect.

Alt-2 processing time varies significantly. Through Professional Certification (where the filing architect self-certifies), approvals can come in days or weeks. Through standard DOB plan examination, processing can take 4–12 weeks. For complex projects in historic districts or with significant structural work, additional review time is common.

In NYC, the application type (Alt-1, Alt-2, Alt-3) IS the permit application — there isn't a separate 'building permit' as in other cities. Once the Alt-2 is approved, a work permit is issued. The terms are sometimes used interchangeably in the context of NYC construction.