21 West 20th Street

The tax lot is 100 feet by 90 feet and carries roughly 89,300 gross square feet in two buildings, of which about 28,110 square feet is residential. Built FAR is 8.79 against a residential FAR of 10.0 in the C6-4A district.

The residential stack divides cleanly in two. The lower floors hold eight essentially identical full-floor residences of roughly 1,302 square feet each, plus one of about 1,270 square feet addressed 19 West 20th Street — one home per floor, served by a private elevator landing, with light front and rear on a 25-foot-wide plate. Above them sit four substantially larger residences of roughly 2,710, 3,774, 4,663 and 4,841 square feet, occupying the widened floors that cantilever over the neighboring building. Those four are a different product from the nine below them: wider, terraced, and priced in a different band from the first sellout onward. One residence also carries a 436-square-foot ancillary unit lot.

The offering plan offered twelve residences and twelve storage lockers. The building as completed carries thirteen. That gap is a plan amendment, not a discrepancy in the physical building, but a buyer's counsel should read the amendment history rather than the original plan alone.

The staffing model is a full-time attended lobby serving thirteen residences — a high service-to-unit ratio and a correspondingly high per-residence cost. There is no gym, no pool and no resident manager in the records reviewed; the amenity here is the elevator opening into your own floor.

The building's finances were not available for this page and are not published. Two questions matter more here than in an ordinary condominium and should be put to the managing agent in writing. First, how the common charges and the reserve are allocated between the residential section and the non-residential unit — the plan carries a separate schedule of charges payable by the non-residential unit owner, and the split determines what thirteen households actually carry. Second, the facade and roof status of the older building, because the upper residences sit on top of it and its exterior is inside the same historic district.

Real estate taxes — the 421-a has burned off. The offering plan projected 421-a exemption benefits, and the assessment roll shows the benefit ran and then ended. On a representative full-floor residence the exemption stood at roughly $34,500 of assessed value on the fiscal 2023 roll and at zero from fiscal 2024 forward; on the largest penthouse it stood at roughly $168,000 in fiscal 2023 and zero thereafter. The same pattern holds on every residential unit lot in the building. There is no exemption of any kind on the fiscal 2027 roll. There is no J-51 — the historical J-51 record shows no benefit anywhere on this tax block — and no 485-x.

For a buyer this is the single most consequential line on the page. Any carrying-cost figure sourced from before fiscal 2024, and any resale analysis that leans on pre-2024 monthly costs, understates the current tax burden materially. Underwrite the actual current bill on the specific unit and nothing else.

Public data describes this as a 1927 loft conversion. It is not.

PLUTO carries a year built of 1927 for tax lot 7506 with an alteration year of 2014, and read alone that reads like a prewar loft renovated into apartments. The underlying records say something different. The residences at 21 West 20th Street were built under a new-building application filed June 2, 2008 for a fifteen-story, 156-foot structure with fourteen dwelling units in occupancy group J-2. Excavation, underpinning and structural filings followed in 2009 and again in 2013. Temporary certificates of occupancy began issuing in March 2016 and the final certificate of occupancy issued January 22, 2019. The Department of Finance carries every residential unit lot at a year built of 2015. The city's building-footprint record dates the structure to 2016.

The 1927 date is real, but it belongs to a different building. The condominium was formed across an assembled site, and it contains a seven-story commercial loft building at 19–25 West 20th Street as a single non-residential unit — 52,797 square feet of office and retail, in tax class 4, dated 1927 on the DOF roll. PLUTO aggregates every building on a condominium billing lot and reports the oldest one. The residences are new; their neighbor inside the declaration is not.

That distinction is not pedantry. It changes the tax analysis, the capital analysis and the comparable set entirely.

Ownership form: Condominium, with a large non-residential unit inside the same declaration that was never offered to residents. Residential transfers proceed by the board's right of first refusal, exercised after a complete purchase package is submitted through the managing agent.

Sponsor control disclosure: The offering plan carries the standard reserved right to rent rather than sell residential units, with the accompanying warning that owner-occupants might never gain control of the board. The sellout completed between 2016 and 2018 and the units are today in separate hands, so the disclosure should be read against the building's actual ownership rather than treated as a live condition — but the plan language is on file and a buyer's counsel will see it.

Financing, pets, pied-à-terre and subletting: Not documented in the records reviewed beyond the standard condominium framework. Pied-à-terre ownership and subletting are ordinarily permitted in a condominium of this type subject to board review; the specific house rules, any sublease term limit, and any financing floor should be obtained from the managing agent.

Flip tax: Not documented. No transfer fee appears in the material reviewed. Confirm before pricing a sale.

Recent sales

Recent closings at this building, curated by The Roebling Team research desk. Prices are the transfer amounts recorded with the NYC Department of Finance; apartment-level detail is checked against the building’s own file in The Roebling Research Library before publishing.

Market read. Most recent trades (2025) cleared a median $2,055/sf across 1 sale. Median listing discount 2.0% from the last ask — a recurring negotiation gap worth pricing into any offer or listing strategy.

Sales sourced from NYC Department of Finance recorded transfers (BBL 1-00822-7506) and verified listing data. Apartment-level facts (line, condition, asking-price context) curated and cross-verified by The Roebling Team research desk. Not all transactions cross-verify with ACRIS records — sponsor and LLC purchases sometimes record at stipulated values rather than market price; square footage from recorded condo declarations and offering plans.

This is new construction from 2015, not a 1927 conversion. Any listing, valuation or comparable analysis that treats it as a prewar loft is working from PLUTO's aggregated year built, which reports the adjoining commercial building.

The 421-a is gone. It ended after fiscal 2023. Pull the current tax bill for the specific unit and build your carry from that. Run the True Monthly Carrying Cost Calculator on real numbers.

The commercial unit is not yours. It is 52,797 square feet of office and retail inside the same declaration, it was never owned by the sponsor and never offered, and it is roughly twice the residential floor area. Read the plan's non-residential-unit section and the schedule of charges payable by that owner, and ask how it votes.

Know which tier you are buying. Nine full-floor homes of roughly 1,300 square feet, four penthouses of roughly 2,700 to 4,800 square feet. They are different products with different buyers and different resale curves.

Landmark constraint is real. The building is inside the Ladies' Mile Historic District by block and lot. Anything visible from the street — windows, terraces, mechanical equipment — runs through the Landmarks Preservation Commission as well as the Department of Buildings.

Get the house rules. Pets, pied-à-terre, sublet terms and any financing floor were not in the material reviewed for this page. The managing agent has them.

Correct the record in your marketing. Buyers and appraisers pull PLUTO. State the new-building application, the 2015 completion and the 2019 final certificate of occupancy plainly, and the architect with it.

Present the tax number first. The 421-a expired after fiscal 2023 and the current bill is the bill. A seller who leads with a clean post-2024 carrying-cost analysis controls the conversation; one who does not will spend it on the defensive.

Sell the plate and the landing. A full-floor home with a private elevator landing on a Ladies' Mile block is a specific product. Thirteen residences will never win on amenities and should not try.

Have the commercial-unit answers ready. Who owns it, how charges are allocated, how it votes. Every buyer's attorney will ask, and the answer is in the plan.

Comparables are thin by design. Thirteen homes in two size tiers. Build the case from small full-floor Flatiron and Ladies' Mile condominiums, and price the specific tier. Run the Seller Closing Cost Calculator against your net expectation.

If you're considering 21W20, also evaluate:

• 32 West 20th Street — Ladies' Mile loft cooperative directly across the street; the prewar co-op alternative on the same block face
• 15 West 20th Street — immediate West 20th Street neighbor; closest micro-location comparable
• 29 West 21st Street — Flatiron loft building one block north; comparable scale
• 31 West 21st Street — Flatiron loft condominium; useful per-foot calibration
• 27 West 19th Street — Flatiron loft building one block south; comparable unit count
• 16 West 19th Street — Flatiron loft building; similar boutique staffing level
• 105 Fifth Avenue — Ladies' Mile building on the corridor's spine; the avenue alternative
• 129 Fifth Avenue — Fifth Avenue loft building in the same district
• 141 Fifth Avenue — landmark Fifth Avenue condominium; the designated-district trophy comparable
• 1107 Broadway — large-scale Flatiron/NoMad conversion; the full-amenity alternative at a different scale
• 7 East 20th Street — East 20th Street condominium; the cross-Fifth comparable
• 39 West 23rd Street — Flatiron condominium a few blocks north; different product, same buyer pool