- Year built
- 2005
- Type
- Cooperative
- Landmark
- No
Every recorded sale at this building, 2006–2026
Price-per-square-foot over time, the line- and floor-premium curves, and every recorded sale.
- Median $/sf
- $1,054
- Listing discount
- 4.8%
- Recorded sales
- 142
- On record
- 2006–2026
4W21 is the rare new-millennium building in the Flatiron that managed to feel of its neighborhood rather than imposed on it. Designed by Hugh Hardy of H3 Hardy Collaboration Architecture for The Brodsky Organization and completed in the mid-2000s, it takes the area's defining grammar — the stone-and-cast-iron loft — and re-renders it in a shimmering, articulated facade of glass and stainless steel. The result is a contemporary building that reads as a respectful descendant of the Flatiron's industrial architecture rather than a generic curtain wall.
Just off Fifth Avenue, the building sits at the practical center of downtown: Union Square, Gramercy, Chelsea, and Midtown all within easy reach. It was conceived as a full-service building for buyers who wanted modern construction, real amenities including an on-site garage, and the lofty proportions the neighborhood is known for — with floor-to-ceiling windows and ceilings approaching ten feet.
Structurally, 4W21 is a cooperative operated as a "condop" — a co-op that functions with much of the flexibility of a condominium. That hybrid is the building's quiet advantage: the maintenance-and-management simplicity of co-op ownership paired with notably looser rules than a traditional pre-war co-op board.
Architecture and unit composition
Hardy's facade is the building's signature — an articulated skin of glass and stainless steel that catches light and echoes the rhythm of the loft buildings around it, modern but grounded in context. Behind it, the homes deliver the proportions buyers come to the Flatiron for: floor-to-ceiling windows, hardwood floors, and ceiling heights near ten feet.
The 54 residences run from one-bedrooms through three-bedroom homes, with a handful of terraced two-bedrooms and two penthouses crowning the building. Kitchens were finished to a high contemporary specification — high-gloss Italian cabinetry, premium appliances, and stone counters — and the open layouts read as updated lofts. The mix favors two-bedroom homes, with the larger and terraced units and the penthouses commanding the building's strongest pricing.
Building operations
4W21 operates as a full-service condop with a full-time doorman and resident staff. For a building of its size, the amenity package is genuinely useful: an on-site parking garage — a real rarity in the Flatiron — plus a fitness room, a roof deck, bicycle storage, and private storage.
The condop structure is the operational headline. Because the building is a cooperative that functions with condominium-like flexibility, buyers generally find a lighter approval process and more accommodating rules than at a conventional co-op, while still benefiting from the single, all-in monthly maintenance and the cohesive management a co-op provides. Specific board policies on financing, subletting, pieds-à-terre, and pets follow the building's proprietary lease and house rules; the structure is designed to be more permissive than the pre-war co-op stock nearby. The location — steps from Fifth Avenue with Union Square, Gramercy, Chelsea, and Midtown transit and retail all close — does the rest.
Local Law 97
- 2024–2029 annual penalty
- $0 (under cap)
- 2030–2034 annual penalty
- $40,298/yr
- Per unit / month range
- $0 – $62
Facade safety — Local Law 11
Safe to live in today — but the last inspection flagged repairs that are due on a deadline, so facade work and its cost are coming. Whether that’s a real concern depends on the scope, the timing, and how the building plans to pay for it — reserves or an assessment — which is exactly what we’d dig into for you.
QEWI = Qualified Exterior Wall Inspector — the licensed engineer the city requires to sign the report (the independent expert, not the managing agent). Source: NYC DOB facade filings (FISP) · The Roebling Research Library.
See the full facade history →Recent sales
Recent transfers at this building, curated by The Roebling Team research desk. Apartment-level facts are independently verified before publishing; sale prices reflect the recorded transfer amount at the NYC Department of Finance.
| Date | Unit | Apartment | Price | PPSF | vs. Ask |
|---|---|---|---|---|---|
| Mar 18, 2026 | 16A | 2 BR · 2 BA · 1,444 sf | $1,550,000 | $1,073/sf | off-mkt |
| Oct 30, 2025 | 10D | 2 BR · 2.5 BA · 1,518 sf | $1,185,000 | $781/sf | -12.2% |
| Sep 17, 2025 | 2D | 2 BR · 2.5 BA · 1,620 sf | $1,435,000 | $886/sf | -2.7% |
| Sep 4, 2025 | 8D | 2 BR · 2.5 BA · 1,495 sf | $1,225,000 | $819/sf | off-mkt |
| May 5, 2025 | 14D | 2 BR · 2.5 BA · 1,518 sf | $1,350,000 | $889/sf | -1.8% |
| Jul 15, 2024 | 4D | 2 BR · 2.5 BA · 1,495 sf | $1,300,000 | $870/sf | -6.8% |
| Jun 28, 2024 | 11B | 3 BR · 3 BA · 1,674 sf | $1,450,000 | $866/sf | -6.5% |
| Jun 27, 2024 | 4B | 2 BR · 3 BA · 1,500 sf | $1,169,561 | $780/sf | -8.2% |
Market read. Most recent trades (2026) cleared a median $1,054/sf across 1 sale. Median listing discount 4.8% from the last ask — a recurring negotiation gap worth pricing into any offer or listing strategy.
Other recent transfers
| Date | Unit | Price |
|---|---|---|
| Oct 14, 2021 | 12A | $1,240,000 |
| Dec 5, 2019 | 2A | $600,000 |
| Nov 19, 2012 | 15B | $4,350,000 |
| Apr 7, 2011 | 11C | $1,395,000 |
| Dec 24, 2008 | 2A | $665,000 |
| Oct 11, 2006 | 15A | $2,545,625 |
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 1-00822-0045) 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 on co-ops is not officially recorded, figures shown are approximate.
What to know if you’re buying
The first thing to understand is the structure: this is a cooperative operated as a condop, which typically means a lighter approval path and more flexible rules than a traditional co-op while retaining co-op simplicity. Confirm the building's current posture on financing, subletting, and pieds-à-terre as part of your offer, since those are the levers that distinguish a condop from a standard co-op. Beyond structure, focus diligence on floor and exposure, the layout and whether the home has a terrace, and the scope of any renovation. The on-site garage is a genuine differentiator in this neighborhood and worth weighing. Review the building's financials and the all-in maintenance, and lean into the location — few Flatiron addresses are this central.
What to know if you’re selling
Lead with the building's distinct combination: a Hugh Hardy-designed glass-and-steel facade, loft-scale homes with near-ten-foot ceilings, a rare on-site garage and roof deck, and the flexibility of condop ownership — a package the surrounding pre-war co-ops and conventional lofts cannot match. Benchmark to comparable Flatiron buildings and emphasize the structure's looser rules to buyers who want condo-like flexibility without condo pricing. Stage to the home's light, ceiling height, and any terrace, and if the sale includes garage access or a deeded space, make it prominent — it is a meaningful draw in this corridor.
Comparable buildings
If you're considering 4W21, also evaluate these Flatiron and nearby downtown peers:
- 15 West 20th Street — Flatiron luxury building a block south
- 16 West 19th Street — boutique Flatiron building nearby
- 16 West 16th Street — established building to the south
- 100 West 15th Street — full-service Flatiron / Chelsea building
- 101 West 24th Street — modern Chelsea / Flatiron tower
The Roebling Team at 4W21
The Roebling Team at Compass specializes in the Flatiron, Chelsea, and Gramercy corridors and the broader downtown market. We publish this profile because buyers and sellers evaluating a hybrid-structure building like 4W21 deserve building-specific intelligence — the architecture, the condop rules, the amenity program including the garage, and where the pricing sits against comparable Flatiron inventory.
If you're considering a purchase or sale at 4W21, a 30-minute consultation is the right starting point.
Get the full picture on this building.
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