29 West 21st Street (Iron Lofts)

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, so any proposal must address LPC review alongside zoning, other permits and property rights. The district designation alone does not establish that unused floor area is impossible to develop.

There is no doorman and no staffed lobby. Listing records describe virtual entry service with remote monitoring; this does not establish in-person staff coverage or a staffing budget. Deliveries and access control run through that system.

With six residential units and a commercial component, capital costs for the façade, roof, elevator and boiler follow the declaration’s common-interest allocations; do not assume an equal six-way division or omit the commercial interest. 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.

Ownership form: Condominium, with no cooperative board approval; confirm the right of first refusal on sale and lease in the declaration and bylaws.

Pets, subletting, pied-à-terre use and financing: Not documented. No offering plan for this building was located in either library, the by-laws are recorded with the declaration, and the 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 additions can require LPC review. Some proposals qualify for staff permits and others require a Certificate of Appropriateness; ordinary maintenance can be exempt, while interior work requiring a DOB permit also requires LPC review.

Real estate taxes: The assessment roll shows no exemption; check the unit's bill for any 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.

Recent sales

Recent closings at this building, from The Roebling Research Library. 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 (2026 to date) cleared a median $1,549/sf (recorded) across 1 sale. Median listing discount 4.7% 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 1-00823-7508; each condominium apartment is its own tax lot). Apartment-level facts (line, condition, asking-price context) curated and cross-verified in The Roebling Research Library. 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.

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