- Year built
- 1909
- Type
- Prewar walk-up apartment house
- Amenities
- Shared rear garden, laundry, bicycle storage and private basement storage
- Landmark status
- Not an individual landmark; in the Park Slope Historic District Extension
- NYC Landmarks Preservation Commission records, updated February 2026
- Pets
- Pets permitted; species and limits not stated
- Washer/dryer
- Permitted
Every recorded sale at this building, 2004–2026
Bedroom-by-bedroom medians, the full transfer record, and how units trade against ask.
- 2BR median, 2023–2026
- $780K
- 5 qualifying sales
- Recent range
- $613K – $900K
- Listing discount
- -2.1%
- Recorded transfers
- 37
Own an apartment here? See what it would sell for.
A Private Pricing Opinion — what your apartment at 423 15th Street 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.
423 15th Street is a purpose-built apartment house with a formal entrance that still carries the name Theodore. Thomas Bennett designed the four-story building around 1909, using Renaissance Revival ornament to give a small walk-up a substantial street presence. Its 16 residences share a garden behind the building, with apartments ranging from compact one-bedrooms to larger two-bedroom layouts.
Architecture and unit composition
An Ionic portico frames the entrance, with the building name carved into its entablature. Upper windows have decorated lintels, and the fourth-floor openings are arched. The cornice combines modillions, dentils and a classical frieze. Brick, stone and pressed metal form the principal exterior materials.
The apartment inventory includes homes of roughly 550–700 square feet and larger layouts approaching 800–960 square feet. Original room arrangements and later alterations produce differences in how living, dining and bedroom space connect. Some larger homes have separate dining areas, while more compact plans use an open living and dining room.
The shared garden supplies outdoor space to owners throughout the building. Upper-floor homes gain height above the street but require a longer stair climb. Private basement storage provides space outside the apartments, and bicycle storage reduces the need to carry bikes upstairs.
Building operations
The cooperative is professionally managed. Common facilities include laundry and the rear garden, and there is space for stroller parking at the first floor. Storage allocations should be checked as part of the apartment's transfer because basement areas are separate from the interior living space.
Historic-district designation covers the ornate entrance and other exterior elements. Repairs to the portico, cornice and street-facing windows take place within that preservation framework. The existing building also exceeds the residential floor-area allowance shown for its present zoning, so the established apartment-house volume is part of the property's value.
Pets and in-unit washer/dryer
- Pets
- Pets permitted; species and limits not statedSource: The Roebling Team's building profile
- In-unit washer/dryer
- PermittedSource: The Roebling Team's building profile
Considering an apartment here? Send Corey the listing to confirm the pet and washer/dryer rules for that apartment.
Own an apartment here? Request an apartment-specific pricing review.
Monthly carrying charges in recent sales
- Maintenance, per room
- $216 per room a monthMedian of 5 recorded sales since October 2023Source: recorded sales, refreshed October 2026
Maintenance as recorded with each sale. A co-op's maintenance already covers the building's real estate taxes and the building's own mortgage, if it has one; add your own loan payment for the monthly outlay. A summary of recorded sales, not a current bill; charges change.
Building staffing and amenities
- Elevator
- NoSource: NYC Department of City Planning records (PLUTO)
- Amenities noted
- Garden, bike storage, storageSource: The Roebling Team's building profile
Staffing and amenities as our building profile and recent listing records describe them. A feature not listed is not confirmed absent. Outdoor space, parking and some facilities can belong to particular apartments or to a separate owner; confirm access for the specific apartment.
Local Law 97
This building is below the 25,000 sq ft threshold at which LL97 limits apply to a building on its own. It is still covered if it shares a tax lot or condominium board with buildings totaling over 50,000 sq ft; confirm on DOB’s covered-buildings list.
See full Local Law 97 analysis →Recent sales
Recent transfers 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.
| Date | Unit | Apartment | Price | PPSF | vs. Ask |
|---|---|---|---|---|---|
| Jul 9, 2026 | 4D | 2 BR · 1 BA · 960 sf | $900,000 | $938/sf | +20.2% |
| Apr 28, 2026 | 2B | 1 BR · 1 BA | $613,000 | -0.3% | |
| Jan 29, 2026 | 1C | 2 BR · 1 BA · 650 sf | $780,000 | $1,200/sf | -2.4% |
| Dec 19, 2024 | 4C | 2 BR · 1 BA | $825,000 | +4.4% | |
| Jul 25, 2024 | 3C | 2 BR · 1 BA | $765,000 | +4.8% | |
| Jul 20, 2023 | 4C | 2 BR · 1 BA | $740,000 | -7.4% | |
| Jul 21, 2022 | 3B | 2 BR · 1 BA | $615,000 | -6.7% | |
| Apr 29, 2021 | 3D | 3 BR · 1 BA | $895,000 | -5.8% |
Market read. Most recent trades (2026 to date) cleared a median $1,069/sf (recorded) across 2 sales. Median listing discount 0.2% from the last ask — a recurring negotiation gap worth pricing into any offer or listing strategy.
The retrade record
Lines that have traded more than once in the public record — the building’s appreciation arc, apartment by apartment.
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 3-01103-0069). 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 on co-ops is not officially recorded, figures shown are approximate.
What would your apartment rent for?
Enter your apartment and I'll send you what it would rent for, from comparable closed leases at 423 15th Street and nearby.
Comparable buildings
- 14 Prospect Park Southwest — A nearby prewar cooperative with a similarly limited residential inventory.
- 459 12th Street — Another small walk-up-era cooperative for comparing apartment scale and shared costs.
- 443 12th Street — A warehouse conversion with cooperative ownership, useful for comparing loft space with a purpose-built apartment plan.
- 125 Prospect Park West — A larger prewar cooperative on the park frontage, offering a different exposure and building scale.
- 86 Prospect Park West — A low-rise prewar cooperative for buyers weighing park-facing rooms against a side-street setting.
More Park Slope buildings
- 420 12th Street (Ansonia Court) — 1880 co-op
- 421 Fourth Street, 421 Fourth Street · Park Slope — 1899 co-op
- 422 Second Street — 1920 co-op
- 426 2nd Street, 426 2nd Street · Park Slope — 1920 condominium
- 427 15th Street — 1909 co-op
- 432 Tenth Street — condominium
The neighborhood
For the full neighborhood — its buildings, character, and market — read The Roebling Team Guide to Park Slope.
The full playbook — what goes in the package, how boards read your financials, the interview, and the timeline — plus sample cover, reference, and personal letters you can adapt.
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. Where this page compares one building or neighborhood to another, that is our analysis of the recorded record — it names the measure, the period and the sample it rests on, and it is an observation about medians rather than a prediction about any particular apartment.
Considering a move at 423 15th Street?
Request a private building brief with the relevant comparable sales, current and off-market availability, and an apartment-specific view of value.
646.939.7375 · c.cohen@compass.com