18 Eighth Avenue

NC2 Architecture filed the conversion in March 2021 as an alteration with a new certificate of occupancy: "renovation of existing building including conversion of existing two (2) family dwelling to four (4) class 'A' dwelling units." Permits issued in February 2022 and the Department of Buildings records a certificate of occupancy on the job in October 2023. The filing describes a five-story, 52-foot building of about 7,263 square feet, counting the basement level that city tax records leave out. Because the house is in a historic district, exterior work required Landmarks Preservation Commission review.

The condominium declaration, dated June 22, 2023, creates four units, A through D. Listing records describe a two-bedroom parlor-floor home of about 1,267 square feet, a three-bedroom Residence A, and a four-bedroom duplex penthouse of about 1,816 square feet. The unit labels in listing records and the lettered units in the declaration do not line up one-to-one in every source; confirm the unit and its floor plan against the declaration.

Per the offering plan filed with the New York State Attorney General (plan CD220081), the plan was submitted April 7, 2022, accepted November 15, 2022 and declared effective June 2, 2023, with Innovative Brownstone Development Fund LP as sponsor. The record lists four residential units and a current total offering price of $8,735,000. It reports one unit sold, a figure it has not updated since the closings. Amendment-level detail was not available from the Attorney General database for this review.

The four recorded deeds total $8,427,753, about $307,000 below the plan's current total, which suggests the last homes sold below their Schedule A prices.

ACRIS shows these sponsor deeds:

• Residence C: $1,525,000, deed dated August 28, 2023
• Residence B: $2,031,409, deed dated September 8, 2023
• Residence D: $2,775,094, deed dated January 30, 2024
• Residence A: $2,096,250, deed dated March 13, 2024

The Residence B deed equals $1,995,000 plus 1.825%, the combined state and city transfer tax rate, which suggests a $1,995,000 contract price with the sponsor's transfer taxes added to the consideration. Listing records give the parlor two-bedroom at $1,995,000, or about $1,575 a square foot. Listing records also report the penthouse at $2,995,000. No deed at that figure was found; the largest recorded deed is $2,775,094. Unit-level transaction history is maintained in The Roebling Research Library and shared with clients during diligence.

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 (2024) cleared a median $1,526/sf (recorded) across 3 sales. Median listing discount 0.0% from the last ask.

Sales sourced from NYC Department of Finance recorded transfers (BBL 3-01059-7501; 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.

Resales only. The sponsor has sold out. Compare any ask with the 2023 and 2024 deeds, and read a grossed-up deed as a lower contract price.

Historic district rules. Windows, the facade, the stoop and any rooftop addition fall under Landmarks Preservation Commission review. Budget time and cost for approvals before planning exterior work.

A four-unit condominium. Ask for the budget, the reserves, the insurance policy and how the declaration splits roof and facade costs.

Closing costs. In a resale the buyer pays the state mansion tax (1% at $1 million, 1.25% from $2 million) and the seller pays the transfer taxes. Use the calculators below to run your price.

If you're considering 18 Eighth Avenue, also look at these Park Slope buildings:

• 10 Eighth Avenue — townhouse cooperative on the same block, in the historic district
• 22 Eighth Avenue — cooperative in a wide brownstone two doors up
• 501 8th Avenue — four-residence condominium conversion of a prewar building
• 408 3rd Street — four three-bedroom condominium homes in a renovated 1920 building
• 409 Third Street — four-home brownstone condominium
• 205 14th Street — five-residence condominium conversion