R3A Zoning NYC
R3A Zoning is a low density residential zoning contextual district in NYC. You can build single family or 2 family homes that are either detached or zero lot line in R3A.
The R3A Zoning District is a contextual sub district of R3 Zoning in NYC. R3A Zoning is mapped in The Bronx, Brooklyn, Queens, and Staten Island.
R3 Zoning Districts
R3 Contextual Districts
R3A Zoning Regulations
The New York City Zoning Resolution is complicated and quite in depth. In this article we will review some basic Zoning Codes with regards to residential zoning district R3A. This analysis does not assume to cover every possible issue, but provide a general overview of the zoning codes.
R3A Zoning Community Facility
R3A Zoning is a residential zone but Community Facility uses are allowed in R3 zones. In the instance of a community facility the zoning calculations may be different as community facilities can have alternate requirements.
R3A Zoning Specifications
Minimum Lot Size: Lot Area & Lot Width
Lot Size Detached or Zero Lot Line:
A Detached house has yards on all sides and does not touch any other buildings or houses. A zero lot line house touches one side property line but does not touch another house.
Minimum Lot width =25 Feet
Minimum Lot Area = 2,375 Sq Ft
R3A Floor Area Ratio (FAR):
Floor Area Ratio determines the floor area that can be built on the property. The floor area ratio is multiplied by the lot area.
FAR = .5
Attic Allowance 20% bonus
In R3A Zoning districts the FAR may be increased by 20% for floor area located under a pitched roof. This is not always possible to achieve.
Density Factor or Dwelling Unit Factor (DU) for R3A
The Dwelling Unit factor determines the maximum number of dwellings or families on the property.
710 – This is used to calculate how many units you can have. The total residential floor area is divided by this factor to get the maximum allowable number of dwelling units. This calculation will let you know if you can build 2 families or only one.
R3A Building Heights:
Perimeter Wall Height = 21 Feet
Building Height = 35 Feet
Yard Requirements for R3A
Front Yard = 10 Feet minimum
Rear Yard = 30 Feet
Side Yards = 8 Feet
R3A Zoning Example
Here is an example zoning analysis. Be aware that zoning is complicated and I am only addressing the basics here. I assure you there are many additional issues and variations to consider beyond this example.
R3A Example Lot
Lets assume we have a 40 foot wide and 100 foot deep property in an R3A Zoning District in The Bronx on an interior lot.
Zoning Floor Area/ Floor Area Ratio (FAR)
So the floor area ratio is .5. The FAR is a ratio that determines how many square feet you can build on the property. You simply take the property size and multiply it by the FAR.
In this example we have:
FAR of .5
Lot Size of 40 feet x 100 feet.
Zoning Floor Area = Lot Area X FAR
Lot Area = 40 x 100
Lot Area = 4,000 sq ft
FAR = .5
Zoning Floor Area = 4,000 sq ft x .5
Zoning Floor Area = 2,000 sq ft
There is a zoning Bonus for Attic allowance of up to 20%. Attic allowance is a little complicated, you will not always be able to maximize the attic allowance. We will assume that we can maximize the attic allowance for this example.
Zoning Floor Area with Bonus 2,400 sq ft
So we can build a 2,400 sq ft house.
How may families can we have on our R3A lot.
Zoning regulates the maximum number of residential units you can put in a building. In this houses we have 2,400 square feet. We then take the zoning Area and divide by the Density factor.
Number Of Families = Zoning Floor Area ÷ Density Factor
Number Of Families = 2,400 ÷ 710
Number Of Families = 3 but actually 2
The actual calculation is for 3 units but unfortunately we can only build a 2 family house because multifamily is not allowed in R3A. Two families would be the maximum.
R3A Zoning Example Conclusion
In this example we are proposing to develop a 2 family house of 2,400 square feet. The buildings would be detached, and will need parking for every family.
Thank You for reading our post on R3A Zoning in NYC.
I hope this was helpful. You can leave questions or comments below. If you want to discuss a specific project or want help with zoning review please feel free to contact Fontan Architecture directly. We will be happy to help.
Author Jorge Fontan AIA
This post was written by Jorge Fontan, a Registered Architect and owner of Fontan Architecture.