R4B Zoning NYC(Last Updated On: April 8, 2019)
R4B Zoning is a low density, contextual residential zoning district in NYC that allows for one family and two family homes. The houses can be built as detached, semi detached, attached, and zero lot line residences.
R4B is a sub district or R4 zoning. Two major differences between R4 and R4B is that R4B does not allow multi family (3 families or more is multifamily). Is mapped in Brooklyn or Queens.
R4 Zoning Districts
R4 Contextual Districts
R4B 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 R4B. This analysis does not assume to cover every possible issue, but provide a general overview of the zoning codes.
R4B Zoning Community Facility
R4B Zoning is a residential zone but Community Facility uses are allowed in R4 zones. In the instance of a community facility the zoning calculations may be different as community facilities can have alternate requirements.
R4B Zoning Specifications
You can only build one or two family homes in R4B. The buildings can be Detached, semi detached, zero lot line, or attached.
Lot Size For Detached or Zero Lot Line
Minimum Lot width =25 Feet
Minimum Lot Area = 2,375 Sq Ft
Lot Size For attached or semi-detached
Minimum Lot width =18 Feet
Minimum Lot Area = 1,700 Sq Ft
Floor Area Ratio (FAR):
Floor Area Ratio determines the floor area that can be built on the property.
FAR = .9
Density Factor or Dwelling Unit Factor (DU)
The Dwelling Unit factor determines the maximum number of dwellings or families on the property.
870 – 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.
Building Height = 24 Feet
Front Yard = 5 Feet
Rear Yard = 30 Feet
Zero Lot Line Side Yards = 8 Feet
Detached = 2 side yards combined adding up to 8 feet
Semi detached = 4 feet
Side yards can be waived for the abutting side(s) of attached buildings. There are requirements for this that must be met to qualify.
1 Parking Space must be provided for each dwelling unit.
R4B 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.
R4-B ZONING EXAMPLE LOT
Lets assume we have a 30 foot wide and 100 foot deep property in an R4B Zoning District in queens on an interior lot. If we are looking to build the most units we can, we would want to divide the lot into 2 different lots.
Zoning Floor Area/ Floor Area Ratio (FAR)
So the floor area ratio is .9. 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 .9
The lot Size is 30 feet x 100 feet.
Zoning Floor Area = Lot Area X FAR
Lot Area = 30 x 100
Lot Area = 3,000 sq ft
FAR = .9 or
Zoning Floor Area = 3,000 sq ft x .9
Zoning Floor Area 2,700 sq ft
So we can build a 2,700 sq ft for the house.
HOW MANY FAMILIES CAN WE HAVE ON OUR R4B LOT?
Zoning regulates the maximum number of residential units you can put in a building. We take the zoning Area and divide by the Density factor.
Number Of Families = Zoning Floor Area ÷ Density Factor
Number Of Families = 2,700 ÷ 870
Number Of Families = 3 but we can only build 2 because 3 families is not allowed.
Maximum Number Of families = We can build a 2 two family house.
R4B ZONING EXAMPLE CONCLUSION
We can build a 2 family house of 2,700 square feet counting the attic. We will need to provide parking for every family.
THANK YOU FOR READING OUR BLOG POST ON R4B ZONING.
I hope this was helpful. You can leave questions or comments below. If you want to discuss a specific project with an architect 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.