The NYC Renovation Permit Process Explained: DOB Alt-1, Alt-2, and Alt-3

Renovating in New York City means working within one of the most regulated building environments in the country. The NYC Department of Buildings (DOB) classifies most renovation work into three alteration types. Knowing which one applies to your project tells you a lot about your timeline, cost, and what professionals you’ll need.

When Do You Need a DOB Permit?

You need a permit any time your renovation affects plumbing, gas, electrical, mechanical systems, or the building’s structure or layout. Purely cosmetic work — painting, flooring, cabinet replacement that doesn’t move plumbing — often doesn’t require a DOB permit, though your co-op or condo board will still likely require an alteration agreement.

If in doubt, assume you need one. Working without a required permit can result in stop-work orders, fines, and problems when you eventually sell.

Alteration Type 1 (Alt-1)

An **Alt-1 permit** is required when the renovation changes the building’s use, egress, or occupancy. In residential terms, this is the permit for major work — combining apartments, changing a layout in a way that affects the certificate of occupancy, or converting space from one use to another.

Alt-1 filings must be prepared by a registered architect or professional engineer, involve the most extensive review, and result in a new or amended certificate of occupancy. This is the most complex and time-consuming permit type.

Alteration Type 2 (Alt-2)

An **Alt-2 permit** covers multiple types of work that do not change the building’s use or occupancy. This is the most common permit for serious apartment renovations — a kitchen or bathroom gut renovation that involves new plumbing and electrical, for example, typically falls here.

Alt-2 work requires licensed professionals for the trades involved and is filed with the DOB, but it doesn’t trigger a change to the certificate of occupancy. Most full apartment renovations that keep the existing layout fall under Alt-2.

Alteration Type 3 (Alt-3)

An **Alt-3 permit** covers a single type of minor work — for example, one specific structural or plumbing change. It’s the narrowest classification and applies to limited-scope projects.

The Board Attestation Step

Under current NYC rules, co-op and condo boards must provide written attestation in DOB NOW confirming they’ve authorized the renovation before the city will process the permit application. This means your board approval and your permit filing are linked — you can’t get the permit without the board’s sign-off on record. Coordinating this step correctly prevents your project from stalling.

How the Filing Process Works

In practice, the sequence looks like this: your contractor and design professionals finalize the scope and drawings, the appropriate permit is filed through a licensed architect or engineer, the board provides its attestation, the DOB processes and issues the permit, work proceeds with required inspections along the way, and the project closes out with final sign-offs.

A contractor experienced in NYC manages this entire sequence so you’re not personally chasing filings, inspections, or sign-offs.

Why This Matters for Your Timeline

Permitting is often the hidden driver of a renovation timeline. The construction itself may take weeks, but board approval plus permit processing can add a month or more before work even begins. Building that reality into your expectations from day one prevents frustration later.

Let MCG Corp Handle the Paperwork

MCG Corp coordinates all DOB permit filings through licensed architects and engineers, manages the board attestation step, and handles inspections and sign-offs end-to-end. You get a renovation that’s done right, on the record, and free of the compliance risks that come with cutting corners — backed by our 10-Year Labor Warranty.