421 West 21st Street, Manhattan
Apartment building · 36 units · built c. 1938 · Block 719, Lot 29.
Building permits
- Alteration, filed Oct 5, 2026, estimated cost $48K, described as “At apt 5C, interior renovation incl new partitions, finishes, fixtures and appliances per plans. No change in use, bulk, egress or occupancy.”
- Alteration, filed Aug 4, 2026, estimated cost $3K, described as “Heavy duty sidewalk shed during exterior repairs filed under application # M01349874, filed sep. Sidewalk shed shall comply with ch #33 of the NYC bc. No change in use, occupancy or egress under this application.”
- Alteration, filed Mar 9, 2026, estimated cost $130K, described as “Window replacement / repair of north facing windows at cellar and floors 1 thru 6 in existing window frame. Installation / removal of safety equipment at facade. No change in egress, use, or occupancy.”
- Alteration, filed May 16, 2023, estimated cost $44K, described as “Installation of new Dish Wireless telecom site. Installing 3 sectors of antennas with associated parts, 6 RRH units, 1 GPS antenna, and 1 equipment cabinet. Service connection in basement.”
- Alteration, filed Nov 30, 2022, estimated cost $25K, described as “Decommission of existing Sprint site. Remove 9 antennas and equipment from the roof. Service connection in basement. Initial installation approved under application #101420179”
- Alteration, filed Jun 29, 2022, estimated cost $26K, described as “File alteration type 2 to combine existing apartment 4F and 5F according to plan, no change of use, egress, or occupancy”
- Alteration, filed Jun 29, 2022, estimated cost $135K, described as “File alteration type 2 to combine existing apartment 4F and 5F according to plan, no change of use, egress, or occupancy. Combining 2 apartments must comply with TPPN 03/97”
Property taxes
- Assessment
- $3,529,800
- 2026–27 tax
- $414,924
- Market value (city estimate)
- $7,844,000
- Taxable value
- $3,335,669
- Assessed land
- $271,800
- Assessed improvements
- $3,258,000
Zoning
R7B: floor area ratio 3.97 built, above the 3.00 base zoning allows, which bonuses, transfers or older rules can permit.
Flood zone
Current FEMA flood map: zone X, minimal flood hazard. FEMA’s preliminary map: zone X, moderate risk: a 0.2% chance of flooding each year.
Recent sales
- Aug 28, 2024: $18,500,000
Open-market sales since 2016, from the Department of Finance’s sales files.
Landmarks
Part of Chelsea Historic District (Historic District). 32 Landmarks Preservation Commission permits are on file.