420 12 Street, Brooklyn

A 1881 walk-up apartment building in the Park Slope Historic District Extension historic district, on 12 Street, zoned R6B.

420 12 Street is a walk-up apartment building in Brooklyn, New York City (BBL 3010980001). The property is zoned R6B, on a 40,800 sq ft lot, with 4 floors and 70 residential units. It was built in 1881. The lot is not inside a FEMA Special Flood Hazard Area. NYC municipal records show 9 open building violations for this lot as of 2026-07-05.

Property facts

BBL	3010980001
Borough	Brooklyn — Community District 6
Neighborhood	Park Slope
ZIP code	11215
Zoning district	R6B
Building class	C6 — walk-up apartment building (what’s a building class?)
Land use	02 — Multi-family walk-up buildings
Lot area	40,800 sq ft
Floors	4
Residential units	70
Year built	1881
FAR	2.68 built · 2 max residential · 0 max commercial Learn: What is FAR?
Historic district	Park Slope Historic District Extension
Flood zone	Not in a FEMA Special Flood Hazard Area

Public records

9 open Department of Buildings violations
0 open ECB (OATH) violations
0 open Housing Preservation & Development violations

Violation counts as of 2026-07-05.

Absence of a record means none on file in NYC municipal records — not a certification of compliance.

The complete dossier also covers:

Buildable floor area (residential & commercial)
Recorded ownership & last sale
Recorded mortgages & open debt stack
LL97 carbon exposure by compliance period
Flood coverage percentage & base flood elevation
Climate projections for this lot
Open permits & construction pipeline
Distress signal convergence
Air rights & transferable development rights
Comparable sales (Pro)

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Data: NYC municipal records (Departments of City Planning, Buildings, Finance) and FEMA. See our sources and methodology. Data as of 2026-07-11.