R4 (Residential Fourth Density)


Faisal Nadeem

R4 Zoning

R4 zoning is a crucial aspect of urban planning, particularly in cities like Ottawa and neighborhoods such as North Corona, Queens, and Arden Heights in Staten Island. This zoning category, part of the R4 family which includes R4F, R4H, R4T, R4A, R4L, R4M, and R4ZZ, allows for a higher density of housing compared to R3-2 districts. With a floor area ratio (FAR) of 0.75 plus an attic allowance, it permits low-rise buildings up to three stories, incorporating detached houses, townhouse, and apartments.

The Zoning By-law and Official Plan ensure that R4 zoning maintains the characteristics of existing neighbourhoods while allowing for development. Front yards must be at least 10 feet deep or a minimum of 18 feet to provide adequate space for parking. Side yards and setbacks are designed to keep the neighbourhood character intact, with detached dwellings requiring two side yards totaling at least 13 feet and semi-detached buildings needing one side yard of eight feet.

The building height in R4 districts can reach 35 feet, with the perimeter wall rising to 25 feet before requiring a setback. This zoning supports various residential use types, including income-restricted housing units (IRHU), which have different off-street parking requirements within the Transit Zone. R4 zoning also allows for mixed-use developments, promoting communities with a blend of residential and commercial spaces.

R4 zoning acknowledges the historical fabric of areas developed in the 1800’s and mid-twentieth century, ensuring compatibility and functionality in urban land use. The design and layout of these zones are intended to enhance the housing stock and neighbourhood character, supporting a mix of single family homes, multi-unit structures, and low-rise apartment buildings.

This balance aims to maintain a stable and vibrant community, while accommodating new development that fits well within the existing context.

R4 Infill

When considering R4 infill housing in R4 zoning districts, the goal is to utilize existing sites to maximize land use efficiently. Infill projects must adhere to specific floor ratio (FAR) and coverage guidelines to blend with the existing neighborhood. Typically, infill developments result in three-story buildings with multiple dwelling units, and parking spaces are essential to the design.

For instance, a typical infill project might include a ground-floor garage and a front yard driveway. These spaces ensure that cars are parked off the street, maintaining a tidy sidewalk appearance.

In R4 zones, various lots and buildings occupy the blockfront, including commercial and manufacturing uses. This mix requires thoughtful regulations to ensure new developments fit the established definition found in Section 12-10 of the Zoning Resolution. The area must meet criteria such as acres and sq.

ft. requirements to support redevelopment. Ensuring Hurricane proof houses is crucial, particularly understanding the base flood elevation meaning in flood-prone regions. Projects must also consider the scale, height, and setback to maintain harmony with the surrounding neighborhood.

R4-1 Zoning

The R4-1 zoning districts are designed for one- and two‑family detached or semi‑detached houses. These districts differ from R3-1 areas by allowing a narrower minimum lot width of 25 feet for detached homes. Despite this, homes in R4-1 districts are typically larger due to the higher floor area ratio (FAR) of 0.75 plus an attic allowance.

The perimeter wall can rise to 25 feet, higher than the 21 feet allowed in R3-1, with a maximum building height of 35 feet. In Middle Village in Queens and Bay Ridge in Brooklyn, these districts showcase their unique zoning features.

In R4-1 districts, two side yards totaling eight feet are required for a detached residence, without a minimum width for each side yard. However, there must be eight feet between buildings on adjacent zoning lots. For semi-detached residences, a four-foot side yard is required on lots at least 18 feet wide. Zero lot line buildings need only one eight-foot side yard.

Front yards must be at least 10 feet deep, and no more than 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 or detached house if the lot is 35 feet or wider. Each dwelling unit must have one off-street parking space.

R4-A Zoning

Understanding R4A zoning is essential for those interested in residential architecture. This zone, along with R3A and R3X, allows for one-family and two-family detached residences. These homes typically have two stories and an attic beneath a pitched roof, with a floor area ratio (FAR) of 0.75, plus an attic allowance.

The lot size and building envelope differ slightly among these districts, which helps shape the unique character of each neighborhood. R4A zones are often found in neighborhoods like Woodlawn and Throgs Neck in the Bronx, featuring houses with a minimum width of 30 feet.

The perimeter wall in an R4A zone can rise to 21 feet before it must slope, leading to a maximum building height of 35 feet. The front yard must be at least 10 feet deep, but it can be deeper to match the adjacent yards, up to 20 feet. The rear yard should be 30 feet deep, and side yards must total at least 10 feet, ensuring ample space between houses.

Parking is typically located in the driveway, garage, or an off-street spot, with specific requirements to prevent cars from jutting onto the sidewalk. If the lot is 35 feet or wider, a garage can be within the house, provided the driveway is at least 18 feet deep.

Each district has its own plan section elevation and base flood elevation meaning, which contribute to the unique variations in building size and area. The mapped layout of these districts helps maintain the typical look of older neighborhoods, with similar but distinct characterized elements. In summary, R4A zoning is designed to create a balanced residential environment with specific requirements that enhance the overall living experience.

R4-B Zoning

In Bay Ridge, Brooklyn, and Middle Village, Queens, R4-B zoning is common. It focuses on low-rise buildings and one-family or two-family attached residences. This district maintains the characteristic streetscape with contextual row house designs. The maximum building height allowed is two-story with a flat-roofed design, often reaching 40 feet.

The floor area ratio (FAR) is 0.9, which controls the total building size. Front yards are required, and new houses must match the depth of adjacent properties, ensuring a harmonious look.

In R4-B, zoning lots typically need to be at least 40 feet wide, but there is no minimum side yard requirement, allowing zero lot line buildings. Off-street parking space is generally required, but curb cuts are prohibited for safety, and waived in certain cases.

This zoning permits detached, semi-detached, and attached buildings, offering flexibility while preserving the streetscape. Frontages are limited to avoid disrupting the area’s look, and buildings are designed to fit into the existing urban fabric.

Continuing issues in R4 zones and multiple-unit dwellings

Oversized dwelling units

The R4 Zoning Review in Ottawa has become a critical discussion point due to the rise of multiple-unit dwellings with unusually high bedroom counts. These oversized dwelling units (ODU’s) often appear in inner-urban neighbourhoods, where new buildings feature apartments with six, eight, or even twelve bedrooms.

This increase in occupancy levels, without thorough planning review like Site Plan Control, has led to issues such as garbage overflow and excessive noise. Moreover, these units raise questions about the adaptability of such housing for various household types, potentially impacting the long-term social health and diversity of communities.

The trend of oversized dwelling units is largely driven by the rising costs of housing and land, along with a significant demand for affordable accommodation. This demand is particularly strong near post-secondary institutions with growing enrollment, attracting students, young singles starting their careers, and low-income service workers.

The CMHC Rental Market Report from Spring 2014 highlights that 96% of apartments have two bedrooms or fewer, making larger units an attractive option for those seeking shared accommodations or occupied units. This growing need for affordable housing in the inner city and downtown areas shows no signs of slowing down. Any effective solution must address this persistent pressure and ensure residents have access to diverse and sustainable housing options.

Rooming houses versus dwelling units

When dealing with R4 zoning, it’s essential to understand the distinctions between a rooming house and a dwelling unit. In my experience, very large ODU’s are often marketed and occupied in ways that make them look more like rooming houses than single household units.

Zoning does not differentiate based on whether occupants are related, but it does distinguish between a dwelling unit, where a single housekeeping unit of members participate in the control and management of the household, and a rooming house, where the arrangement is more about individual tenants dealing directly with the landlord and less about joint management by occupants.

This issue has been recognized in the R4 Review, which aims to examine if zoning definitions can be clarified or if new rules are needed to ensure clear distinctions between rooming houses and other multi unit developments.

Lot consolidations and larger apartment buildings

In my experience, the demand for housing often leads to older buildings being demolished to make way for new development. This is especially true in areas with an aging stock of existing houses. These lots are then consolidated to accommodate a single larger building, raising important questions about how such changes affect the lot fabric, streetscapes, and the fine grain of the neighbourhood.

This element of character is essential, as it defines the essence of the community. As the lots combine and the buildings grow, the overall development must be carefully managed to maintain the integrity of the neighbourhood. The integration of new and old structures influences the streetscapes and the way people experience their environment. It’s a balance between meeting the demand for modern housing and preserving the neighbourhood’s unique character.

Garbage storage

In high-occupancy buildings, management of garbage and recyclables can be tricky, especially on smaller lots. Current zoning rules don’t cover garbage storage, leaving it to Site Plan Control. This can be a problem for units with oversized dwelling space and occupancy similar to an apartment building. Adding provisions for storage in the Zoning By-law can help builders avoid nuisance issues for neighbours.

Location of air conditioning units

When placing air conditioning units in multi-unit buildings, it’s important to think about noise and exhaust. Neighbours in R4 zoning areas need consideration to reduce the impact on their homes. Taking measures to position air conditioners thoughtfully can enhance comfort for everyone involved.

Diversity of new housing stock

Zoning rules help develop new, cost-effective, low-rise, medium-density housing in urban areas for urban households who can’t afford a single or semi-detached house or a mid- to high-rise elevator building. The Official Plan gives direction to promote a balance of housing types and tenures to offer a full range of housing for various demographic profiles in the General Urban Area.

This includes R4-zoned areas. The R4 review is an opportunity to promote development of mid-density, ground-oriented housing in these areas, gradually increasing density and diversity of the housing stock in urban neighbourhoods while maintaining compatibility.

Building design and compatibility

Design and appearance of new buildings in infill development often cause concern. Regulating these aspects is not easily accomplished through zoning due to disagreement and differences in taste. Some prefer older, historic architectural styles while others lean towards modern styles. In any case, compatibility with the surroundings is essential.

Development subject to Site Plan approval can address building design, unlike projects needing only a building permit. Sensitivity in new buildings is vital for building design and appearance to harmonize with existing styles. The ability to address building design is generally not possible where only a building permit is required.


What does R4 mean in construction?

In R4 zoning, buildings and structures can house between five to 16 persons. These portions are supervised and residential, providing a safe environment. Excluding staff, residents live on a 24-hour basis and receive custodial care. This setup is perfect for those needing consistent support.

What does R4 zoning mean in NSW?

The R4 zone in NSW is for residential flat buildings but also allows single dwellings, dual occupancies, multi dwelling houses, and secondary dwellings. This housing type is suited for both large and small sites. These dwellings are all permissible in this zone, helping to realize diverse residential developments.

What is R4 zoning in Ontario?

R4 zones in Ottawa are meant for low-rise buildings up to four storeys. These zones allow walk-up apartments, apartment buildings, and stacked dwellings. The main aim is to fill the missing middle with no more than four units per building, providing more apartments.

What does R4 zoning mean in NYC?

R4 zoning in New York City permits various types of houses. Each lot must have a front yard at least ten feet deep, ensuring uniformity with the neighboring yard. Additionally, a rear yard must be at least thirty feet deep. Every lot also requires an off-street parking space.