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Multifamily Alteration

Apartment + condo alterations, renovations, + envelope work.

2.6M permits classified across 26 metros

Browse multifamily alteration permits in New York City →
Definition

What it covers

Multifamily alteration permits cover changes to existing apartment and condo buildings — unit-level reconfigurations, common-area overhauls, structural retrofits, roof replacements, and substantial systems work. The highest-volume multifamily segment in most US metros because turnover + aging-stock maintenance dominate filings against existing buildings.

Methodology

How a permit lands in Multifamily Alteration.

Every silver permit flows through a two-stage classifier. The deterministic stage maps the structured signals — work_class, the normalized permit type, and the building sub-type — into the segment vocabulary where the mapping is unambiguous. The machine-learning stage handles the cases that aren't direct lookups: multi-vocab permit-type strings, ambiguous occupancy spans, and jurisdictions that bundle categories. The segment is the classifier's output, the same axis across every metro — so multifamily_alteration means the same thing in NYC as in LA even though the upstream jurisdictions emit completely different raw permit-type strings.

When the signal genuinely isn't there, we say so. A row with no assignable segment degrades honestly — to its work-nature, then to its raw source type, and only to “Unclassified” when truly nothing is known. We never guess a segment to fill a gap; an honest Unclassified is the floor, and field-level data-quality flags surface when the classifier had low confidence. That restraint is the point — the classification is only worth selling on if the “don't know” is honest.

Coverage

Multifamily Alteration by metro — where it’s moving

Where multifamily alteration permits are classified today, ranked by volume — with each metro’s momentum (the last 90 days vs the prior 90) so you can see where the segment is heating up in your territory. Momentum shows only where we have enough filings to stand behind it. Metros with recent activity link straight into the live browse.

Busiest metro right now: New York City — last 90 days vs the prior 90
Prior 90d11,437
Last 90d9,798

-14% vs prior 90d

Alert me when Multifamily Alteration momentum crosses a threshold.Single-window signal (last 90 days vs the prior 90) — at most once a week, no account.
+%

Email when Multifamily Alteration momentum in New York City crosses +25%.

Find Multifamily Alteration contractors near your branchEnter your address — see who’s pulling these permits in your radius.
Recent

Recent multifamily alteration permits

Real permits classified into Multifamily Alteration in the last 30 days.

  • 1991 BroadwayMEP / Plumbing$9K2026-08-26New York City
  • 22 Halsey StreetMEP / Mechanical / HVAC$10K2026-08-26New York City
  • 22 Halsey StreetAlteration / Commercial$10K2026-08-26New York City
  • 219 East 84 StreetAlteration / Commercial$55K2026-08-26New York City
  • 265A Nassau AvenueFoundation / Only$25K2026-08-26New York City
  • 2055 Ryer AvenueOther$1K2026-08-26New York City
Who sells into this

Who tracks Multifamily Alteration.

Multifamily Alteration is a sales-intelligence segment for suppliers and reps targeting multifamily developers and general contractors. Filter it by metro, rank the contractors pulling these permits, and see the projects worth selling into — the same way across every covered market.

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