Remodeling a house in Gerritsen Beach, Brooklyn

What this page covers

This page is for owners of the small one- and two-family houses of Gerritsen Beach planning kitchen, bathroom, basement or whole-interior work. Gerritsen Beach is a Brooklyn neighborhood, so building permits come from the NYC Department of Buildings (DOB). DCP's statistical area for it also includes Sheepshead Bay and Manhattan Beach, so this page uses a narrower set: the tax lots that PLUTO places in Special Coastal Risk District 4 (CR-4), which the Zoning Resolution names as Gerritsen Beach. All of those lots with homes are in one census tract. Structural alterations, additions, elevation and new construction are not planned services. Availability and service-area approval have not been established.

Zoning

Special Coastal Risk District 4

The Zoning Resolution's Special Coastal Risk District exists to protect public health, safety and welfare in coastal areas at exceptional flood risk, including by limiting how many people live in flood-prone areas. Section 137-11, last amended May 12, 2021, lists CR-4: Gerritsen Beach, Brooklyn Community District 15. Section 137-21, last amended December 5, 2024, sets the residential uses allowed there:

• on zoning lots under 3,000 square feet, detached or semi-detached single-family residences;
• on zoning lots of 3,000 square feet or more, detached or semi-detached single- or two-family residences;
• in every Special Coastal Risk District, no ancillary dwelling units, qualifying residential sites or qualifying senior housing.

For an interior project, this matters most when a plan would change how many homes the house holds. Converting a basement, attic or ground floor into a separate apartment is the kind of change these rules address. A CR-4 house may also be an older building that does not match today's rules. Before you design a basement or ground floor around a second unit, have a design professional confirm what the zoning and the Certificate of Occupancy allow for your lot. A tax lot and a zoning lot are not always the same.

CR-4 tax lots

What the lot data shows

The median tax lot with a home here is 1,800 square feet. On both flood measures this is a different picture from the nearby Marine Park statistical area, where about a quarter of lots with homes are flagged on the 2015 map. In CR-4, nearly every lot is. A flag means only that part of the lot touches the mapped floodplain, and DCP says year-built values are accurate to the decade, not the year. Look up your address on FEMA's Flood Map Service Center and see the city's NYC Flood Maps page, which says flood insurance is still based on the 2007 maps while FEMA revises the 2015 preliminary maps.

From summer bungalows to year-round houses

DCP's 2017 Resilient Neighborhoods study describes how the housing got here. An early-20th-century summer resort of one-story wooden bungalows grew until, by the 1930s, the peninsula was filled with bungalows close together on small lots with no backyards. Over time those seasonal buildings became year-round two-story houses. The study describes most buildings as two-story one- and two-family detached homes, often covering most of their lots, with few complying with today's front and rear yard rules.

It also records that Hurricane Sandy's surge in 2012 filled basements and reached the first floors of most homes. For a remodel, that history means a house may have been enlarged, converted and repaired several times. Ask for existing drawings and permit records, expect hidden conditions behind finishes, and treat the basement as a separate decision. See renovating an older home and the basement moisture guide.

When a renovation becomes a flood-code project

The same DCP study explains a threshold that matters for whole-house work. It defines a substantial improvement as repair, reconstruction, rehabilitation, addition or improvement costing 50% or more of the building's current market value. A substantially improved building must meet the flood-resistant construction rules of Building Code Appendix G. A building that is not new, substantially damaged or substantially improved does not have to meet Appendix G, provided the changes do not increase its noncompliance. The study adds that substantially improved homes in Gerritsen Beach were, on average, required to raise the lowest occupied floor to a design flood elevation three to five feet above grade, and more along the waterfront.

So the size of the budget, not only the type of room, can change what a renovation must include. For whole-house plans, have a design professional estimate where your scope stands against the substantial-improvement threshold before you fix the scope. Elevation itself is structural work and is not a planned service here. The Marine Park page lists the Appendix G basement items DOB has presented for older buildings. The study dates from 2017, so confirm the current rules and maps with a professional.

Address worksheet before asking for proposals

1. Look up the address on both FEMA maps and note the zone and any base flood elevation shown.
2. Confirm whether the lot is mapped in CR-4 and note the tax-lot area. Ask a professional whether the zoning lot is the same.
3. Note the legal unit count and basement use on the Certificate of Occupancy, if there is one.
4. Split the brief into an upper-floor package and a basement or ground-floor package.
5. For a whole-house plan, ask for an early estimate of the scope against the 50% substantial-improvement threshold.
6. Gather existing drawings, permit records and any post-2012 repair records.

Room scope examples are on home renovation, basement remodeling and bathroom remodeling. The whole-home planning guide helps decide what comes first.