155 15th Street (Harbor Hill)

The building is five stories and about 50 feet tall, per the new-building application, over an excavated garage. DOB filings from 2008 record underpinning of the neighboring foundations and a soldier-pile retaining system for a 14-foot excavation. The lot is mid-block on the north side of 15th Street, so the street-facing residences face south. Listing records describe oversized south-facing windows, open kitchens and private balconies.

There are 21 residences: four on the first floor, five on each of floors two through four, and two on the fifth floor, which are the building's penthouse units. The offering plan's Schedule A lists each residence with its assigned storage unit, and balconies or terraces for many lines. Schedule A and listing records show a mix of one- and two-bedroom layouts. The first-floor units with outdoor space and the two fifth-floor residences are the stock that stands apart. Note the plan's own warning that listed square footages are measured to the exterior face of exterior walls and the midpoint of demising walls, so usable floor area is smaller than the Schedule A figure.

Parking is deeded and scarce. The eleven garage units are separate condominium units with their own common-interest percentages. Under the plan, each garage unit's share of the common elements carries a 150% weighting for the garage's higher utility, insurance and maintenance cost. With eleven spaces for 21 residences, a space conveys as a separate deed and prices as a separate asset.

The offering plan's first-year budget provided for a visiting part-time superintendent, gas PTAC heating in the recreational area, a gas-fired heater in the garage, and an elevator maintenance contract. The condominium is professionally managed. At five stories the building sits below the six-story threshold of the city's façade-inspection program (FISP/Local Law 11). Condominium financial statements from 2012 through 2016 are on file in the Compass Offering Plan Library. Anything current — budget, reserves, assessments, the garage's share of expenses — should come from the managing agent.

Ownership form: Condominium. Resales are subject to the board's right of first refusal rather than share-transfer approval.

Garage units: Deeded separately from residences, with their own common-charge allocation. Confirm whether the declaration or by-laws restrict garage-unit ownership to residential unit owners before buying or selling a space on its own.

Pets, leasing, pied-à-terre and financing: Not documented in the records available to us. The standard condominium framework applies. Request the current house rules and any leasing restrictions in writing.

Real estate taxes: 421-a at 20% for 2026/27, the final year. Underwrite the full unabated bill from 2027/28.

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 $1,200/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 0.0% from the last ask.

Sales sourced from NYC Department of Finance recorded transfers (BBL 3-01041-7502; 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.

Use the 2027/28 tax number. The 421-a is at 20% this year and ends June 30, 2027. The increase is modest, but the full-tax figure is the correct one to use.

Confirm the unit count in your own file. It is 21 apartments and 11 parking spaces. Counts above 21 in secondary records include parking.

If you want parking, ask early. All eleven spaces are held by residents. A space becomes available only when its owner sells it.

Read the plan's measurement note. Schedule A square footages overstate usable floor area. Measure, or rely on the recorded floor plans.

Present the tax position plainly. The benefit is nearly exhausted, so little phase-out remains; future bills still change with assessments, rates and other benefits. Say so, with the DOF figures.

Decide how to sell the parking space. If you own one, choose early whether to include it, price it separately, or keep it. The building's own residents are the most likely buyers of a separate space.

Lead with exposure and outdoor space. South-facing light and balconies on a mid-block South Slope street are what set this building apart. Photograph them first.

If you're considering 155 15th Street, also evaluate:

• 205 12th Street, a 2019 South Slope condominium; the newer-construction alternative nearby
• 228 13th Street (The Ainsley), a 2023 South Slope condominium; current product with a newer tax position
• 229 9th Street (Luna), a South Slope and Gowanus-edge condominium; comparable buyer pool, purpose-built plates
• 500 4 Avenue, a 2010 Fourth Avenue condominium permitted in the same era
• 575 Fourth Avenue, a larger 2018 Fourth Avenue condominium a few blocks south
• 343 4th Avenue (Novo), a 2006 Fourth Avenue condominium with garage parking
• 251 7th Street (The Argyle), a 2009 Park Slope condominium; a same-era, small-building peer
• 675 Sackett Street (Park Slope Terrace), a 2004 Park Slope condominium whose 25-year 421-a has only begun to phase out; the opposite tax position