450 Warren Street

The lot is 12,500 square feet, 100 feet by 125 feet, in the M1-4/R6A district the 2021 Gowanus rezoning laid over these blocks. Building area on the tax roll is 32,004 square feet — roughly 27,069 residential and 4,935 commercial. The new-building application proposed 31,700 zoning square feet across five stories and 55 feet, R-2 occupancy, eighteen dwelling units.

The stack is legible from the condominium tax lots. Residences run five per floor on the second, third and fourth levels — lines A through E — and three on the fifth, lines A through C, where the building steps back. That is eighteen. Below them, three separately deeded commercial units occupy the ground floor. Nine parking units sit on their own tax lots. Thirty lots in total, exactly as the September 2021 subdivision application described.

The courtyard is the plan. Rather than a double-loaded corridor, the building wraps a central open void; the stair spirals through it; and the walkways that serve the apartment doors are open to the air, screened with curved wire mesh that admits light, planting and weather. Balconies project from the perimeter behind tensioned stainless-steel mesh. The upper-level setbacks that make the fifth floor a three-unit floor also generate the terraces that distinguish the top of the stack.

The practical consequences of open-air circulation deserve to be stated plainly, because they are the reason to buy here and the reason to underwrite carefully. The courtyard-side openings provide opportunities for daylight and ventilation; inspect the specific apartment's operable windows and airflow rather than assuming a comparison with all corridor buildings. Against that, the common areas are exposed to weather year-round, which changes what maintenance means: drainage, snow and ice, screen and mesh condition, planting, and the stair itself are all ongoing operating exposures rather than one-time capital items. The condominium's operating statements include landscaping, irrigation and pest control; compare the actual scope and costs with specific alternatives.

Because the building sits outside any historic district, window replacement, terrace work, façade repair and rooftop projects need no Landmarks review; they run through the Department of Buildings, where a permit is required, and the board. On a custom terrazzo façade that can be a meaningful saving in both time and cost if repair is ever required — and a custom façade is exactly the kind of assembly for which a buyer should ask about warranty status and any completed remediation.

Eighteen apartments and three commercial units share the building and courtyard operating costs. The operating statements on file for 2023 and 2024 show total income of roughly $202,000 and $211,000 respectively against total expenses of roughly $194,000 and $188,000 — modestly positive in both years, with the improvement in 2024 driven mostly by lower electricity and water. Those positive operating results do not establish reserve adequacy or the absence of deferred work; review the current reserve balance, liabilities and capital plan.

The expense profile tells you what kind of building this is. Insurance is the largest fixed block at roughly $37,000 a year, and it includes a standalone flood policy of about $7,200 alongside general and property liability, umbrella, directors and officers, and crime coverage. Electricity is the largest single utility, at roughly $53,000 in 2023 and $44,000 in 2024 — a substantial house-electric load for eighteen units, consistent with a building whose circulation, courtyard and stair are lit and drained rather than merely heated. Payroll runs modestly, with a superintendent line and total payroll expense of roughly $24,000 in 2023 and $21,000 in 2024; this is not a staffed building. Security and intercom, including camera monitoring, runs roughly $17,000 to $22,000 a year, which is high relative to the unit count and reflects a building with multiple exterior openings and an open courtyard.

The compliance lines are worth reading as a picture of the building's regulatory posture: Local Law 84/133 energy benchmarking, Local Law 88 lighting and submetering, a parapet inspection, Department of Environmental Protection backflow device compliance, elevator reporting, and a tax certiorari engagement. Elevator maintenance and third-party witnessing run roughly $6,000 to $10,000 a year. There is one elevator.

In January 2025 the board approved an 8 percent increase in common charges effective February 1, 2025, with no retroactive charges, stating that the budget needed to cover the full cost of annual operations, continuous funding of the capital reserve, and contingencies. That stated rationale does not establish the adequacy of reserves or rule out an operating or capital shortfall. Ask for the current reserve balance and for any assessment history, and ask specifically what the reserve is being built toward.

Management history and the current agent are maintained in The Roebling Research Library and confirmed with clients during diligence.

Purchase and resale: A full application package goes to the Board of Managers through the managing agent — signed contract with riders, last year's signed tax returns, an employer letter stating position and salary, two personal and two business references, a broker-supplied credit check, and the window guard, lead paint and carbon monoxide forms. $600 non-refundable application fee, $500 buyer move-in deposit, $500 seller move-out deposit, certified check or money order only. The board's remedy in a condominium is its right of first refusal rather than approval of the purchaser; confirm the waiver mechanics and the timing clock in the by-laws so the closing schedule is built correctly.

Pets: Permitted with the written consent of the Board of Managers or the managing agent. Two pets per unit maximum, and no dog over 30 pounds. Consent is revocable. Pets must use the designated elevator and must be carried or leashed in public areas.

Noise and floor covering: Unless the board authorizes otherwise, not less than 60 percent of the floor area of each unit — excluding kitchens, pantries, bathrooms, closets and foyers — must be covered with rugs, carpeting or equally effective noise-reducing material. No music between 10:00 p.m. and 9:00 a.m.; no noisy repair work except weekdays between 10:00 a.m. and 5:00 p.m. absent an emergency.

Alterations: Board consent and an executed alteration agreement are required before any work begins, with a damage deposit set at the board's discretion. Construction hours are weekdays 8:30 a.m. to 4:30 p.m., with elevator deliveries between 10:00 a.m. and 2:00 p.m., and no work on weekends or holidays. Contractors must name the condominium and each unit owner as additional insureds.

Air conditioning and exterior work: No ventilator or air conditioning device may be installed without prior written board approval, which the rules place in the board's sole discretion. No exterior signage, aerials or projections without approval.

Terraces and roof: Shared balconies, roof decks and terraces are reserved to the unit owner and accompanied guests. No additional wood decking or fencing without prior written board approval, no objects placed directly on roof surfaces, no storage of waste. Quiet hours apply on outdoor space after 10:00 p.m. General roof access is otherwise prohibited except where the roof is part of a lawful terrace and the resident is present.

Property taxes: No 421-a or other benefit appears on the Department of Finance exemption roll; check the unit's tax bill for any abatement. Run True Monthly Carrying Cost against the actual current bill.

Flip tax, financing minimums, sublet term: Not documented in the materials reviewed. Confirm at offer stage.

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 $1,580/sf (floor-adjusted) across 2 sales. Floor-adjusted means each sale is restated to a constant mix of floors, so the figure can differ from the plain median of the sales listed above. Median listing discount -0.9% over ask.

Sales sourced from NYC Department of Finance recorded transfers (BBL 3-00399-7502; 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.

Search the right BBL, and do not be surprised by the address. The Department of Finance calls this lot 193 Bond Street. It is the same corner parcel. Every construction and title record says 450 Warren Street.

Confirm the certificate of occupancy status in writing. The permanent issued April 6, 2026. Ask whether any conditions remain open and get the answer on paper before you commit.

Walk the building in bad weather. The corridors are outdoors. That is the design, and it is genuinely excellent — but you should experience it in February and in rain before you decide it suits you.

Model the actual tax bill. The roll shows no 421-a or other exemption; confirm on the unit's bill. If you are comparing against abated Gowanus product, put both on an after-tax monthly.

Read the insurance schedule, including flood. The condominium carries a standalone flood policy. Ask what the building's flood zone determination is, what the deductible is, and whether any claim has been made.

Budget the application process. $600 application fee, $500 move-in deposit, full financial package to the board, and a few weeks for review. Build it into the closing schedule.

Price parking separately. Nine fee parking units on their own tax lots. If the apartment carries one, it is a distinct asset with its own value and its own tax line.

Lead with the architecture, specifically. This is SO–IL's first New York condominium, the façade is custom terrazzo masonry, and the circulation is an open-air courtyard with a five-story stair. Describe those specific design features and their practical maintenance requirements without a neighborhood-wide uniqueness claim.

Photograph the courtyard and the corridor. The single hardest thing to convey in a floor plan is that the hallway is outdoors. Show it.

Get ahead of the certificate of occupancy. The permanent issued in April 2026 after four years of temporaries. A buyer's attorney will find it. Present the current status first.

Get ahead of the tax and flood questions. Both come up. Both have straightforward answers. Neither improves with delay.

Anchor the fifth floor separately. Three units on a setback level with terraces is a different product from the five-unit floors below.

If you're considering 450 Warren Street, also evaluate:

• 344 Degraw Street — the earlier generation of purpose-built condominium on the same Boerum Hill–Gowanus blocks
• 345 Carroll Street — Carroll Gardens condominium of similar vintage with deeded parking, cabana and storage units
• 323 Bergen Street (Bergen Brooklyn) — the newest large condominium nearby, and the scale contrast to this building's eighteen units
• 509 Pacific Street (The Hendrik) — boutique Boerum Hill condominium with a deep service roster and, like this building, no residential abatement
• 556 State Street (Boerum Heights) — earlier Boerum Hill new construction with parking and storage sold separately
• 199 State Street (The Lookout Hill Condominium) — small condominium on the Boerum Hill–Brooklyn Heights line
• 76 Schermerhorn Street (The Symon) — boutique condominium of comparable unit count to the north
• 71 Smith Street (The Boerum) — mixed-use condominium on the Smith Street spine, the nearest full-service alternative