R4 districts allow all types of housing at a slightly higher density than permitted in R3-2 districts. The floor area ratio (FAR) of 0.75, plus an attic allowance of up to 20% for inclusion of space under the pitched roof common to these districts, usually produces buildings with three stories instead of the two-story homes characteristic of R3 districts. Much of the residential development in North Corona in Queens and Arden Heights in Staten Island is typical of R4 districts.
To accommodate a potential third floor beneath a pitched roof, the perimeter wall in R4 districts may rise to 25 feet before being set back to the maximum building height of 35 feet. Front yards must be 10 feet deep or, if deeper, a minimum of 18 feet to provide sufficient space for on-site parking. Cars may park in the side or rear yard, in the garage or in the front yard within the side lot ribbon; the driveway must be within the side lot ribbon unless the lot is wider than 35 feet. Detached houses must have two side yards that total at least 13 feet and each one must be at least five feet wide. Semi-detached buildings need one side yard with a minimum width of eight feet. The maximum street wall length for a building on a single zoning lot is 185 feet. One off-street parking space is required for each dwelling unit.
On a block entirely within an R4 district (without a suffix), optional regulations may be used to develop infill housing in predominately built-up areas. Infill regulations may be used if at least 50% of the area of the block is occupied by zoning lots developed with buildings, and the lot does not exceed 1.5 acres (65,340 sq. ft.) However, infill regulations may not be used to redevelop a lot occupied by a one- or two-family detached or semi-detached house unless the blockfront is predominantly developed with attached or multifamily housing or commercial or manufacturing uses. Infill regulations can be found in the definition of predominantly built-up areas in Section 12-10 of the Zoning Resolution.
On sites that qualify for infill housing, the higher floor area ratio (FAR) of 1.35 and lot coverage of 55%, as well as more relaxed parking requirements, permit developments with greater bulk and more dwelling units than are otherwise permitted in R4 districts. Infill regulations typically produce three-story buildings with three dwelling units and two parking spaces—one in a ground-floor garage and the other in the front yard driveway. Infill regulations can also produce small apartment buildings.
To ensure that infill housing generally conforms to existing neighborhood scale, height and setback regulations for R4 infill housing are the same as for R4 districts. The maximum street wall length for a building on a single zoning lot is 185 feet. Front yards must be at least 18 feet deep to prevent cars parked in the front driveway from jutting onto the sidewalk. Off-street parking is required for two-thirds of the dwelling units.
R4-1 contextual districts, like R3-1 districts, permit only one- and two‑family detached and semi‑detached houses. Despite a narrower minimum lot width of 25 feet for detached homes, houses in R4-1 districts tend to be larger than those in R3-1 districts because of the higher floor area ratio (FAR) of 0.75 plus an attic allowance. The perimeter wall may rise to 25 feet, compared to 21 feet in R3-1 districts, before sloping or being set back to a maximum building height of 35 feet. Sections of Middle Village in Queens and Bay Ridge in Brooklyn are R4‑1 districts.
Two side yards that total eight feet must be provided for a detached residence. There is no minimum width for each side yard but there must be eight feet between buildings on adjacent zoning lots. One four foot side yard is required for each semi-detached residence, which must be on a lot at least 18 feet wide. Zero lot line buildings, permitted in R4-1 districts, require only one eight foot side yard. Front yards must be at least 10 feet deep and at least as deep as an adjacent front yard but need not exceed a depth of 20 feet. Parking must be within the side or rear yard or in a garage. An in-house garage is permitted within a semi-detached house, or in a detached house if the lot is 35 feet or wider. One off-street parking space is required for each dwelling unit.
R4A contextual districts are similar to R3A and R3X districts in that only one- and two-family detached residences are permitted. Differences in the maximum permitted floor area ratio (FAR) and minimum required lot size, however, result in variations in the typical building envelope found in each district. Characterized by houses with two stories and an attic beneath a pitched roof, R4A districts have an FAR of up to 0.75 (plus an attic allowance) and a minimum lot width of 30 feet. The districts are usually mapped in older neighborhoods, such as Woodlawn and Throgs Neck in the Bronx.
As in R3A and R3X districts, the perimeter wall of a house may rise to 21 feet before sloping or being set back to the maximum building height of 35 feet. A front yard must be at least as deep as an adjacent front yard and at least 10 feet deep, but it need not exceed a depth of 20 feet. A 30 foot deep rear yard, and two side yards that total at least 10 feet with a minimum width of two feet each are also required. There must be at least eight feet between buildings on adjacent lots. Parking must be located in the side or rear yard and the driveway must be within the side lot ribbon. If the lot is 35 feet or wider, a garage is permitted within the house, provided the driveway is at least 18 feet deep to prevent cars from jutting onto the sidewalk. One off-street parking space is required for each dwelling unit.
Primarily a contextual rowhouse district limited to low-rise, one- and two-family attached residences, R4B districts also permit detached and semi-detached buildings. However, the floor area ratio (FAR) of 0.9 and maximum building height of 24 feet typically produce a two-story, flat-roofed rowhouse. Parts of Bay Ridge in Brooklyn and Middle Village and Brookville in Queens are mapped R4B.
To maintain the characteristic rowhouse streetscape of R4B districts, the front yard of a new house must be at least five feet deep and at least as deep as one adjacent front yard but no deeper than the other, although it need not exceed a depth of 20 feet. Detached houses must have two side yards totaling at least eight feet; there is no minimum width for a side yard but there must be at least eight feet between buildings on adjacent zoning lots. Zero lot line buildings require only one eight foot side yard and semi-detached buildings require one side yard at least four feet wide. One off-street parking space is required for each dwelling unit, although parking is waived when only one space is required. Front yard parking is not allowed. Curb cuts are prohibited on zoning lot frontages that are less than 40 feet.