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    Historic Park Slope Carriage House Title is generated by Realmo AI

    860 Union Street, Brooklyn, NY 11215

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    Claim this Listing
    For Sale
    $3,750,000

    MULTI_FAMILY - Brooklyn, NY

    Property size:
    3,894 SF
    Lot size:
    0.06 Acres
    Price / SF:
    $963/SF
    Added:
    May 14, 2025
    Days on Market:
    380
    Last Refresh:
    May 27 at 11:06 pm

    Property Features for 860 Union Street

    General Information

    Property type
    Residential Multi Family
    Property subtype
    Other
    Zoning
    R7B
    Bedrooms
    6
    Bathrooms
    6
    Rooms
    Bathroom 3, Bedroom 6, Bedroom 5, Bathroom 2, Bathroom 4, Bathroom 5, Bedroom 3, Bedroom 2, Bedroom 4, Bathroom 6, Bedroom 1, Bathroom 1
    Interior features
    Laundry Area, Refrigerator, Stove, Washer, Window Treatments
    Basement
    Full
    Standard status
    Active
    Size
    3,894 SF
    Lot size
    0.06 Acres

    Taxes and HOA fees

    Tax Annual Amount
    24181

    Building Details

    Floors in Building
    2
    Number of units
    2
    Flooring type
    Hardwood
    Building materials
    Brick
    Roof type
    Flat

    We can help!

    Listing Contact
    Billy Apter
    Billy Apter

    Listing agent Billy Apter License #BEA5721

    Listing office RE/MAX Real Estate Professiona 6423 11th Avenue, Brooklyn, NY

    Listing date May 14, 2025

    MLS# 492575 Listing URL

    Copyright © 2026 Brooklyn New York Multiple Listing Service. All rights reserved. All information provided by the listing agent/broker is deemed reliable but is not guaranteed and should be independently verified.

    HighLights

    • The property listing points are missing. I need the key selling points to create the property listing highlights.

    Overview

    Located in the Park Slope neighborhood of Brooklyn, New York City, this building was originally constructed as the Victorian Gothic carriage house of the Maxwell mansion, which existed between 1875 and 1922. The 25-foot wide carriage house received a new facade in 1923 designed by Caughey & Evans. As one of the few remaining carriage houses in Park Slope, it is considered a local attraction. The property is situated within the Park Slope Historic District, a short distance from the park. The building is configured as a two-family residence, each unit featuring 3 ensuite bedrooms, a formal living room, a formal dining room, and a kitchen. The property offers potential for conversion into a single-family mansion. Architectural details include mantle fireplaces, built-in China cabinets, parquet floors, stained glass, and tall ceilings. The property is located in the heart of prime Park Slope, surrounded by amenities. The lot size is 0.0599 acres, and the property size is 3894 square feet.
    Property Profile Location Intelligence

    Current Use by Public Records

    Duplexes

    Suggested Use

    Law Firm Restaurant Real Estate Agency Spa & Massage Center Hair Salon Dental Office Nail Salon Food Market Grocery & Convenience Store Gym & Fitness Center

    Zoning and permitted uses should be independently verified with local authorities.

    Location Insight

    • Map
    • Local Demand
    City
    Brooklyn
    County
    Kings
    State
    New York
    Longitude
    -73.973794
    Latitude
    40.67357

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    FAQs

    What type of property is this?
    Duplex - Unique two-family residence or single-family conversion opportunity in Brooklyn.
    Where is this duplex located?
    The property is located at 860 Union Street Brooklyn, NY.
    What is the asking price?
    The asking price for this property is $3,750,000.
    What are key features of this property?
    This property features: The property listing points are missing. I need the key selling points to create the property listing highlights.
    (718) 532-2000
    We can help!
    Listing Contact
    Billy Apter
    Billy Apter
    Real Estate License ID: BEA5721
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    Realmo Value Estimations

    Realmo estimates a property’s market value using a proprietary methodology that incorporates public data and user-submitted information. This cumulative value is generated by integrating a variety of conventional and innovative methods. 

    Disclaimer

    These figures are not official appraisals and should not be used as a substitute for a valuation performed by a licensed appraiser.
    Actual market value may differ due to factors not captured in the data. Estimates are offered for informational purposes only, and users should conduct independent research before making financial or investment decisions.
    By using this feature, you acknowledge that Realmo is not responsible for actions taken based on these estimates.

    AI approach

    Realmo AI Method estimates property value using machine learning models trained on millions of comparable listings, transactions, and market signals. It analyzes property features, location intelligence data, and current market dynamics to predict the most probable market value in real time.

    Realmo CapRate Calculation

    Realmo calculates the Capitalization Rate (Cap Rate) to help estimate a property's potential return on investment. The Cap Rate is a fundamental metric in commercial real estate that measures the relationship between a property's net operating income and its market value.

    How We Calculate Cap Rate

    Cap Rate Formula:
    Cap Rate (%) = (Net Operating Income / Property Value) × 100

    Net Operating Income (NOI) Formula:
    NOI = Area × Lease Rate × (1 - Vacancy Rate) × (1 - Operating Expense Ratio)

    Components

    Net Operating Income (NOI) represents the annual income a property generates after operating expenses:

    • Area: Building square footage from property records
    • Lease Rate: Annual $/sqft based on market data for the property type and geographic location
    • Vacancy Rate: Percentage of unoccupied space based on market data for the property type and location
    • Operating Expense Ratio: Operating costs as a percentage of income, varies by property type

    Property Value is derived from:

    • Recent sale price (if available)
    • Statistical models using comparable sales
    • AI-powered valuation estimates

    Example Calculation

    For a 100,000 sqft Office Building:

    • Lease Rate: $25.00/sqft/year (market data for Office in this area)
    • Vacancy Rate: 8% (market data for Office in this area)
    • Operating Expense Ratio: 35% (typical for Office properties)
    • Property Value: $15,000,000

    Step 1: Calculate NOI

    NOI = 100,000 × $25.00 × (1 - 0.08) × (1 - 0.35)
    NOI = 100,000 × $25.00 × 0.92 × 0.65
    NOI = $1,495,000/year

    Step 2: Calculate Cap Rate

    Cap Rate = ($1,495,000 / $15,000,000) × 100
    Cap Rate = 9.97%

    Property Type Considerations

    Net Operating Income calculations vary by property type due to different operating expense ratios:

    • Office: Higher expenses (30-40%) for HVAC, utilities, maintenance
    • Retail: Moderate expenses (25-35%) for common area maintenance
    • Industrial/Warehouse: Lower expenses (15-25%) for minimal tenant services
    • Multifamily: Moderate expenses (35-45%) including property management
    • Self-Storage: Lower expenses (25-35%) due to minimal maintenance

    Market lease rates and vacancy rates are specific to each property type and geographic location, reflecting local market conditions.

    Disclaimer

    These calculations are estimates for informational purposes only and should not be used as a substitute for professional financial analysis or appraisal.

    • Cap Rate calculations depend on market data that may change over time
    • Actual operating expenses, lease rates, and vacancy rates may differ from market averages
    • Individual property conditions, lease terms, and tenant quality significantly impact actual NOI
    • Property value estimates are approximations and not official appraisals
    • Cap rates vary widely by market, property condition, and investment risk profile

    Professional Guidance Recommended: Before making any investment or financial decisions, consult with licensed appraisers, commercial real estate brokers, and financial advisors who can evaluate your specific property and circumstances.
    By using this feature, you acknowledge that Realmo is not responsible for investment decisions or actions taken based on these estimates.

    Cap approach

    Capitalization Method calculates value based on estimated net operating income (NOI) and applying a market-based capitalization rate (cap rate), we estimate what a typical investor might be willing to pay for it.

    Comparable approach

    Comparable estimate is based on recent sales of similar nearby properties, adjusted for factors like size, condition, and location.

    Relative

    Relative property class coefficient uses factors that account for typical price differences between various asset types (e.g., retail vs. industrial) to provide a more accurate market-aligned estimate.

    Geo

    Comparable Sales Method, enhanced by Geo coefficients — location-based adjustment factors that reflect differences in price levels across neighborhoods, cities, or regions ensuring a more accurate, market-sensitive valuation.

    Stat Estimate

    This method estimates value based on actual market adjusted recent (~5 years) sales of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all similar sales ($/sqft) are above this value
    • Range-to: 75% of all similar sales ($/sqft) are below this value
    AI Estimate

    This method estimates value based on AI market estimation of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all estimations ($/sqft) are above this value
    • Range-to: 75% of all estimations ($/sqft) are below this value
    Alternative use

    Estimate considers the property’s potential value if used for a different purpose-based on zoning, demand, and market feasibility.

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