851 Carroll Street
851 Carroll Street, Brooklyn, NY 11215
Park Slope, Brooklyn
BBL 3010687505 · BIN 3024832
- Year built
- 1894
- Type
- Condominium
- Units
- 5
- Floors
- 4
- Landmark status
- Not an individual landmark; in the Park Slope Historic District
- NYC Landmarks Preservation Commission records, updated February 2026
Every recorded sale at this building, 2021–2026
Price-per-square-foot over time, the line- and floor-premium curves, and every recorded sale.
- Median $/sf, 2026 to date
- $1,245
- 1 sale
- Listing discount
- 0.0%
- Recorded sales
- 6
- On record
- 2021–2026
Own an apartment here? See what it would sell for.
A Private Pricing Opinion — what your apartment at 851 Carroll 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.
851 Carroll Street is an 1894 brownstone in the original 1973 Park Slope Historic District, on the Prospect Park end of Carroll Street. It was rebuilt as a five-unit condominium. The sponsor bought the building in December 2021 and filed in 2022 to renovate the interior and combine its ten apartments into five, using the Department of Buildings' TPPN 3/97 procedure. TPPN 3/97 is the Department of Buildings technical bulletin that lets an owner combine apartments without a new certificate of occupancy, provided use, egress and occupancy don't change. Structural, mechanical and plumbing permits followed through 2024. The condominium was declared in July 2024, four units closed between July 2024 and October 2025, and the last closed in August 2026.
The result is a less common way to own in the brownstone blocks, where row-house apartments often trade as co-op shares or the house sells whole. This one is a fee-simple condominium with five deeded units, no co-op board and no share structure. The combination matters for value too: going from ten apartments to five produced larger homes, roughly 900 to 2,100 square feet, in place of small rental floor-throughs.
Architecture and unit composition
LPC records the building as a neo-Renaissance brownstone row house designed and built by William Flanagan in 1894. Every row house from 815 to 863 Carroll Street on this blockfront is in the historic district. The 20.5-foot brownstone front is landmark-protected, and the 2022–24 work was filed as interior renovation with no change to use, egress or occupancy.
The five units are stacked through the house. The largest, Unit 1, is about 2,130 square feet per the Department of Finance, which on a 20-foot house points to more than one level. Unit 2 is about 1,290 square feet. Units 3, 4 and 5 are about 910 to 940 square feet each, consistent with one unit per upper floor. The Department of Finance does not show floor-by-floor layout, private outdoor space or elevator service. Confirm all three against the offering plan and the floor plans.
City records disagree with each other here: PLUTO carries 1920 and 25 units, and older records carry ten apartments. The primary sources are clear: an 1894 house, ten apartments before 2022, five condominium units since 2024.
Building operations
A five-unit condominium has no staff, and a single bad year can move its costs a lot. DOB filings record boiler removal and mechanical-system replacement during the conversion; confirm that work was completed and its current condition. Ask what heats the building now and whether heat is metered to each unit or runs through common charges. With five units, one roof or facade repair lands on very few shoulders; review the current budget, any reserve and any assessments. Because the building is in a historic district, facade and window work goes through LPC review, which adds time and cost.
Policy framework
Condominium, not condop. ACRIS shows unit deeds on separate tax lots 1401–1405 and a recorded condominium declaration and floor-plan filing. There is no cooperative corporation and no share transfer. Buyers take title by deed, and lenders underwrite the unit, not a co-op's share structure.
Taxes. No 421-a, J-51 or other exemption appears on any roll. The current tax bill is the full bill, so there is no step-up risk. A two-year-old conversion's assessed values can still move as the Department of Finance catches up with the new configuration, though. Check the Notice of Property Value.
Governance and rules. With five units, the sponsor's plan and by-laws set almost everything: leasing, pets, any right of first refusal, reserve funding, insurance. None of it is on file here. Read the offering plan and its amendments before signing a contract.
Financing. Lenders sometimes treat very small condominiums differently from larger ones. Tell your lender early that the building has five units.
Monthly carrying charges in recent sales
- Common charges + taxes, per room
- $391 per room a monthMedian of 5 recorded sales since October 2023Source: recorded sales, refreshed October 2026
- Common charges + taxes, per square foot
- $2.01 per square foot a monthMedian of 5 recorded sales since October 2023Source: recorded sales, refreshed October 2026
Common charges plus real estate taxes, combined into one monthly figure the way New York condominium listings show them. Add a mortgage payment for the monthly outlay. A summary of recorded sales, not a current bill; charges change.
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
851 Carroll competes with whole brownstones, brownstone co-ops and condops, and the small boutique condominiums between Seventh Avenue and Prospect Park West. It prices per square foot at the renovated, historic-district end of the Park Slope condominium market, with Unit 1 pricing as the house's large unit and the upper units against full-floor brownstone apartments. With only five units and a sellout that finished in 2026, the building has almost no resale history. Sponsor pricing is the only benchmark so far, and the first true resale will set the building's market. Unit-level transaction history is maintained in The Roebling Research Library and shared with clients during diligence.
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.
| Date | Unit | Apartment | Price | PPSF | vs. Ask |
|---|---|---|---|---|---|
| Jul 30, 2026 | 1 | 2 BR · 2.5 BA · 2,147 sf | $2,672,906 | $1,245/sf | +3.0% |
| Oct 15, 2025 | 4 | 2 BR · 2 BA · 908 sf | $1,900,000 | $2,093/sf | -3.8% |
| Jul 26, 2024 | 5 | 2 BR · 2 BA · 936 sf | $1,795,000 | $1,918/sf | +0.0% |
| Jul 23, 2024 | 2 | 2 BR · 2 BA · 1,287 sf | $2,300,000 | $1,787/sf | +0.0% |
| Jul 19, 2024 | 3 | 2 BR · 2 BA · 908 sf | $2,119,162 | $2,334/sf | +0.9% |
Market read. Most recent trades (2026 to date) cleared a median $1,245/sf (recorded) across 1 sale. Median listing discount 0.0% from the last ask.
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 3-01068-7505; 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.
What would your apartment rent for?
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Buying here? Condo closing costs with a mortgage typically run 3 to 6% of the price. See NYC co-op and condo closing costs, line by line.
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What to know if you’re buying
Get the offering plan. Almost nothing about governance is in the public record. The plan, its amendments and the first budget are the whole rulebook.
Price in five-owner economics. Any capital cost splits five ways. Ask for the reserve balance and whether any work from the conversion is still under warranty.
Confirm what the 2022–24 work covered. DOB shows permits for interior renovation, plumbing, mechanical and structural work. Ask for sign-offs on each job and the current certificate-of-occupancy status.
Landmark rules apply to the outside. Windows, the facade, the cornice and any rooftop work need LPC approval.
Comparable buildings
- 9 Prospect Park West — the 1929 park-front cooperative at the end of this block
- 205 12th Street — a six-unit Park Slope condominium; the closest match on size
- 86 Prospect Park West — two walk-up apartment buildings run as one co-op, the ownership model this condominium sits beside
- 10 Montgomery Place — walk-up co-op in the historic district, one street south
- 412 8th Avenue — condominium conversion of two walk-up apartment buildings
- 190 Garfield Place — condominium conversion of a 1905 building
- 636 Warren Street — condominium conversion of three walk-up buildings
More Park Slope buildings
- 808 Eighth Avenue — 1904 co-op
- 82 Sterling Place — 1882 condominium
- 84 Sixth Avenue — 1884 condominium
- 853 Carroll Street — 1920 condominium
- 86 Prospect Park West — 1908 co-op
- 862 Carroll Street — 1889 condominium
The neighborhood
For the full neighborhood — its buildings, character, and market — read The Roebling Team Guide to Park Slope.
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 851 Carroll Street?
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646.939.7375 · c.cohen@compass.com