Should GCs ignore Alt-2 filings?

Most of the time, yes for net-new GC pursuit. Exceptions include commercial spaces that signal a tenant move-in, or an existing client relationship.

Where do the Index approval numbers live?

Borough, neighborhood, and approval-by-work-type tables with CSVs are on the NYC Preconstruction Activity Index at getpermitpipeline.com/research/preconstruction-index/nyc/. Method notes are on the same research pages.

NYC Alt-1 vs Alt-2: which alteration filings move, and how long they take

Q: Does every Alt-1 get a TCO?

No. Some go straight to a final Certificate of Occupancy. Temporary Certificates of Occupancy show up when occupancy is needed before every last item is closed.

A contractor's guide to DOB alteration types, Certificates of Occupancy, and measured plan-exam timing · By Josh Steinman · September 10, 2026

Short answer: In New York City, Alteration Type 1 (Alt-1) is the major path — it changes use, egress, or occupancy and usually needs a new or amended Certificate of Occupancy. Alteration Type 2 (Alt-2) covers multi-trade work that does not change use or occupancy and typically ends in a Letter of Completion. New Building is its own class. The labels matter because they change the review path, the end document, and how long you have to research the owner before a bid list hardens.

Note: Timelines and approval rates below are directional measures from public DOB filings, not promises. Real jobs vary by scope, self-cert vs standard plan exam, borough office, and referrals (Landmarks, FDNY, zoning).

Data note: Analysis based on NYC Department of Buildings DOB NOW public filings (Socrata w9ak-ipjd) and related issuance data as loaded by PermitPipeline. Index approval rates are from the NYC Preconstruction Activity Index (Edition 1). Declared values are applicant-reported. Named parties and status can change after filing. A filing is an opportunity signal, not proof a project is open or awarded.

Who this is for

BD and preconstruction: know which alteration class is worth a call this week.
GC owners: spot owner-led change-of-use work before the team is set.
Estimators: skip short-fuse Alt-2 noise unless it signals a tenant move-in you care about.

Alt-1 vs Alt-2 vs New Building in one table

Filing	What it usually means	End document	Why contractors care
Alt-2	Multi-trade work, no change in use/occupancy/egress	Letter of Completion	Fast path; often too short to chase as a "new GC" lead
Alt-1	Change of use, occupancy, or egress (incl. many conversions / major gut jobs)	New or amended Certificate of Occupancy (sometimes via TCO first)	Longer review; clearer owner-led signal
New Building (NB)	Ground-up on the lot	New Certificate of Occupancy	Longest clock; relationship play, not a quick close
Alt-3	Limited / single-trade minor work	Completion paperwork	Usually not a commercial pursuit

Mislabeling is expensive. Filing an Alt-1 scope as Alt-2 is a classic kickback: DOB sends it back, the clock resets, and everyone who was watching the wrong class of filing misses the real signal.

What a Certificate of Occupancy and a TCO are (in plain English)

A Certificate of Occupancy (C of O) is the document that says the space may be occupied for a stated use. New buildings and Alt-1 jobs that change occupancy generally need one. Alt-2 / Alt-3 work that does not change occupancy usually does not.

A Temporary Certificate of Occupancy (TCO) lets people occupy when the building is substantially safe but not fully finished. In NYC practice TCOs are time-limited (commonly discussed as ~90-day renewals) until a final C of O issues. For contractors, a live Alt-1 / NB filing on the way to a TCO or C of O is often where fit-out, MEP, and specialty scopes are still being bought.

Measured: how Alteration CO filings are clearing plan exam

Most NYC alterations that are professionally self-certified move in days. The interesting variance is on standard plan examination.

The Preconstruction Activity Index measures, for April cohorts under standard plan exam, what share of filings were approved within 120 days — same maturity window for each year:

Work type (standard plan examination)	Apr 2025 cohort	Apr 2026 cohort	Change
Alteration CO	41.3% (104 of 252)	25.1% (52 of 207)	−16.1 pts
New Building	25.8% (39 of 151)	13.9% (15 of 108)	−11.9 pts
Alteration (broader class)	87.6% (2,005 of 2,288)	86.0% (1,545 of 1,797)	−1.7 pts

Source: NYC Preconstruction Activity Index — approval processing. Self-certified filings are excluded from this comparison because they follow a different path.

Two limits before you quote that number

Maturity. Filings from about April 27 onward had not fully reached day 120 when the Index extract was taken, so the true year-over-year drop is at most ~16 points and is probably a little smaller.
The data shows who was approved inside the window, not why the rest were not. Open objections, referrals, and applicant delays all look the same in the public status field.

We also recomputed the Alteration CO cut at 115, 110, 105, and 100 days; the direction held. The New Building drop on the same page does not survive that robustness check as cleanly — treat NB as directional, not the headline.

For contractors, the practical read is simple: change-of-occupancy alterations under full plan exam are clearing more slowly than a year ago. That stretches the public window between filing and a locked team.

Typical calendars (directional)

From PermitPipeline's practitioner framing of DOB NOW filings and issuance feeds (see also How long does an NYC building permit take?):

Job type	Typical filing → issuance	What pushes it longer
Alt-2 (no use change)	2–4 weeks	Missing prior approvals
Alt-1 (use / egress / occupancy change)	4–10 weeks	Objections, ZRD-1, agency referrals
New Building	3–9 months	Zoning, environmental, long objection cycles

Quartiles on the same how-long article show why averages lie: combined alterations can show a 16-day median because self-cert floods the left side of the distribution, while Alteration with new C of O sits nearer a ~116-day median filed-to-issued among jobs that have both dates. Use the class that matches the filing in front of you.

A realistic Alt-1 week-by-week (outreach lens)

Day 0 — Job application files; appears in DOB NOW quickly.
Days 0–14 — Intake / examiner queue. Owner still shaping scope; GC often not locked.
Days 14–28 — First objections. Architect responding. Warmest research window for many mid-market jobs.
Days 28–56+ — Objection rounds. GC selection often happening here.
Later — Approval, then permit issuance; bid list frequently narrower.

Alt-2 compresses that calendar. By the time you finish a full owner research pass, many Alt-2 jobs are already moving or done — unless the filing is a commercial TI signal you specifically chase.

How to read an alteration filing without getting fooled

Job type / work type first. Alt-1 / Alteration CO vs Alt-2 vs NB.
Self-cert vs standard exam. Self-cert is a different clock.
Named parties. Owner, applicant, architect of record, GC if present.
Related filings. Subsequent and post-approval amendments attach to jobs already open — they are activity on an existing project, not a brand-new job (see the Index pipeline composition).
Borough and neighborhood. Volume and mix differ sharply across the city; the Index neighborhood CSV is free to download.

FAQ

Is Alt-1 always "bigger" than Alt-2?

Usually in regulatory weight, not always in dollar value. A large Alt-2 renovation can outspend a small Alt-1 use change. The C of O requirement is the cleaner split.

Does every Alt-1 get a TCO?

No. Some go straight to a final C of O. TCOs show up when occupancy is needed before every last item is closed.

Should GCs ignore Alt-2?

Most of the time, yes for "net-new GC" pursuit. Exceptions: commercial spaces that signal a tenant move-in, or an existing client relationship.

Where do these Index numbers live?

Borough, neighborhood, and approval-by-work-type tables (with CSVs) are on the NYC Preconstruction Activity Index. Method notes are on the same research pages.