29 West 21st Street (Iron Lofts)
29 West 21st Street, New York, NY 10010
Flatiron
BBL 1008237508 · BIN 1015529
- Year built
- 1909
- Type
- Condominium
- Units
- 6
- Floors
- 7
- Landmark
- No
Every recorded sale at this building, 2024–2026
Price-per-square-foot over time, the line- and floor-premium curves, and every recorded sale.
- Median $/sf
- $1,549
- Listing discount
- 4.7%
- Recorded sales
- 7
- On record
- 2024–2026
Six residences is a small building even by Flatiron standards, and the structure behind those six residences is unusual enough to be the reason to read this page carefully.
The building went up in 1909 as a store-and-loft structure to designs by James E. Ware & Sons — the office whose defining New York commission is The Osborne on West 57th Street, and whose work on the side streets of Ladies' Mile is much less known. LPC designation records describe a neo-Renaissance elevation in buff brick with iron, on a lot of roughly twenty-five and a half feet by ninety-nine. It is a narrow, tall, single-loft building: exactly the kind of structure that produces full-floor residences when it is converted, because there is no room to do anything else.
The conversion itself came in two distinct steps separated by fifteen years, and the gap matters. In November 2007 the sponsor filed for interior demolition; in May 2008 it filed the Alteration Type 1 application to convert the building to residential use, with a full sprinkler replacement and a new boiler following in 2008 and 2009. But the building was not subdivided into condominium units then. It remained a single tax lot — carried by the Department of Finance as a converted elevator apartment building — until August 2022, when the sponsor filed with DOB to create the condominium lots. The declaration is dated April 2023 and was recorded in March 2024, and the first individual closings followed in April 2024.
That sequence explains what a buyer sees in the public record: a building that has been residential since 2009 but whose condominium is barely two years old. All six residential units have now transferred to separate buyers, in closings recorded between April 2024 and March 2026, with the seventh unit lot transferring separately in early 2025. The sellout is complete, and there is no remaining sponsor inventory.
The second structural fact is the landmark status, and it is the one most often missed here. The lot is inside the Ladies' Mile Historic District, designated in 1989 — but PLUTO's historic-district field for this tax lot is empty. The LPC building database keys the district to this exact BBL, and the designated address is recorded as 29 West 21st Street. Any diligence built on PLUTO's landmark field alone will conclude, incorrectly, that this building is unregulated.
Architecture and unit composition
The building is seven stories on a lot of about 2,500 square feet, carrying roughly 13,700 square feet of residential area. That produces one residence per floor through the residential stack — full-floor lofts, with duplex configurations at the top of the building — plus a small commercial component at the base, where DOB filings record restaurant use through the early and mid-2000s.
Because the lot is an interior mid-block site with buildings on both flanks, light comes from the front and rear elevations only. Ceiling heights and window openings are those of a 1909 loft, which is the reason full-floor plates in a building of this width read as generously as they do. The residences carry key-locked elevator access, so each floor opens directly into a single home; there is no public corridor above the ground floor.
One zoning note that is easy to misread: the lot sits in a C6-4A district with a residential floor-area ratio well above what the building actually uses. The building is materially under-built relative to what the zoning would permit. It is also inside a historic district, which means that unused development potential is not practically realizable on this site — LPC review, not zoning, is the binding constraint.
Building operations
There is no doorman and no staffed lobby. Listing records describe a virtual lobby attendant — remote-monitored entry rather than on-site coverage — which is the common solution in buildings too small to fund a payroll. Deliveries and access control run through that system.
With six residential owners, this is about as small a denominator as a Manhattan condominium gets. Every capital item — facade cycle, roof, elevator modernization, boiler — is shared six ways, and a single significant project produces a large per-unit number. The mechanical systems are relatively young: the sprinkler system was replaced in full in 2008 and the boiler in 2009, and remedial facade repairs were carried out in 2008 and 2009 under a sidewalk shed and pipe scaffold. Even so, a buyer should read the current budget and reserve position, ask about the most recent Local Law 11 filing cycle, and understand that facade work in the Ladies' Mile Historic District carries an LPC review step that adds both time and cost.
Policy framework
Ownership form: Condominium, with the standard right of first refusal on sale and lease rather than cooperative board approval.
Pets, subletting, pied-à-terre use and financing: Not documented. No offering plan for this building was located in either library, and the by-laws and house rules are not in the public record. Because the condominium is new, its house rules may still be evolving; confirm each item with the managing agent at offer stage.
Landmark constraint: The lot is inside the Ladies' Mile Historic District. Window replacement, storefront work, rooftop equipment and any visible addition require LPC review, and material exterior work requires a Certificate of Appropriateness.
Real estate taxes: No abatement. Because the condominium unit lots were created in 2022 and 2023, their assessment history is short; underwrite from the current bill on the specific unit rather than from a projection.
Local Law 97
This building is below the 25,000 sq ft threshold at which LL97 emissions caps apply. No regulatory capital pressure from this law specifically, current or 2030.
See full Local Law 97 analysis →Facade safety — Local Law 11
The latest available FISP filing classified the facade as Safe — no repairs were required at that inspection. Facade inspections run on a fixed five-year cycle; future inspection, repair, and any assessment decisions remain building-specific.
How to read this, and where it comes from
QEWI = Qualified Exterior Wall Inspector — the licensed engineer the city requires to sign the report (the independent expert, not the managing agent).
Penalties shown are amounts DOB assessed against filings on record across 2015–20 to 2020–25. The FISP dataset does not record whether they were paid, contested or remain open, so treat the figure as history rather than a current balance and confirm the building’s standing with the managing agent.
Source: NYC DOB facade filings (FISP) · The Roebling Research Library. City record last verified September 2026.
Recent sales
Iron Lofts prices as boutique Flatiron loft product — full-floor and duplex residences valued per square foot, with the premium concentrated in the upper floors and the duplex configuration at the top of the stack. The comparable set is the small conversions on the Flatiron side streets between Fifth and Sixth Avenues, not the larger amenitized condominiums on Fifth Avenue and Park Avenue South, whose operating economics and buyer pools are different.
Two things shape underwriting here. The first is the six-unit denominator: buyers should look at the budget and reserves rather than at the monthly common charge in isolation. The second is that the building has essentially no resale history — every residence was a first sale between 2024 and 2026 — so pricing depends on line-specific and floor-specific analysis against neighboring buildings rather than on an internal building average.
Unit-level transaction history is maintained in The Roebling Research Library and shared with clients during diligence.
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.
| Date | Unit | Apartment | Price | PPSF | vs. Ask |
|---|---|---|---|---|---|
| Feb 25, 2026 | 5 | 2 BR · 3 BA · 2,082 sf | $3,225,000 | $1,549/sf | -2.1% |
| Jun 26, 2025 | 2 | 2 BR · 3 BA · 2,082 sf | $2,850,000 | $1,369/sf | -4.8% |
| Sep 24, 2024 | PH | 3 BR · 3.5 BA · 2,797 sf | $4,300,000 | $1,537/sf | -13.9% |
| Jun 6, 2024 | 3 | 2 BR · 3 BA · 2,082 sf | $3,195,000 | $1,535/sf | +0.0% |
| Apr 19, 2024 | MAIS | 2 BR · 2.5 BA · 2,584 sf | $2,850,000 | $1,103/sf | -4.8% |
| Apr 16, 2024 | 4 | 2 BR · 3 BA · 2,082 sf | $3,100,000 | $1,489/sf | -4.5% |
Market read. Most recent trades (2026) cleared a median $1,549/sf across 1 sale. Median listing discount 4.7% from the last ask — a recurring negotiation gap worth pricing into any offer or listing strategy.
Full closing history with price-per-square-foot over time, the complete retrade record, and every line that has traded.
Sales sourced from NYC Department of Finance recorded transfers (BBL 1-00823-7508) 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.
Comparable buildings
If you're considering 29 West 21st Street, also evaluate:
- 4 West 21st Street — the closest peer by block and vintage; loft conversion on the same street
- 40 West 22nd Street — small Ladies' Mile loft building directly behind, with the same historic-district constraints
- 15 West 20th Street — boutique Flatiron conversion one block south
- 16 West 19th Street — comparable small loft condominium in the same corridor
- 141 Fifth Avenue — landmarked Fifth Avenue conversion; the serviced, higher-priced alternative
- 105 Fifth Avenue — Ladies' Mile conversion on the avenue rather than the side street
- 22 West 26th Street — full-floor loft condominium a few blocks north
- 7 East 20th Street — small Flatiron loft building east of the avenue
- 175 Fifth Avenue — the Flatiron Building itself; the corridor's landmark benchmark
The neighborhood
For the full corridor — architecture, schools, transit, and pricing across Flatiron — read The Roebling Team Guide to Flatiron.
How to read the facts on this page. Items attributed to an offering plan describe the building as it was offered at that filing — unit mix, square footage, the amenity program as planned. They are not a statement about how the building operates today. Tax and compliance figures are sourced separately to current City records and carry their own dates. House rules, staffing and fee policy can change by board resolution without any public filing: treat every policy line here as a starting point for diligence and confirm it with the managing agent.
Considering a move at Iron Lofts, per listing and brokerage records?
Request a private building brief with the relevant comparable sales, current and off-market availability, and an apartment-specific view of value.
Own an apartment here? See what it would sell for.
A Private Pricing Opinion — what your apartment at Iron Lofts, per listing and brokerage records would likely sell for today, what it costs to sell, and what you’d walk away with — reviewed personally against condition, exposures, renovation quality, and the competition actually on the market.