R3X Zoning NYC

by | Last updated Jul 3, 2020 | NYC Zoning

R3X Zoning is a low density residential zoning contextual district in NYC. You can only build single family or 2 family homes that are detached in R3X.

The R3X Zoning District is a contextual sub district of R3 Zoning in NYC. R3X Zoning is mapped in The Bronx, Brooklyn, Queens, and Staten Island.


R3 Zoning Districts

R3 Contextual Districts


R3X 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 R3X. This analysis does not assume to cover every possible issue, but provide a general overview of the zoning codes.

R3X Zoning Community Facility

R3X 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.


R3X Zoning Specifications

Minimum Lot Size: Lot Area & Lot Width

Lot Size:

A Detached house has yards on all sides and does not touch any other buildings or houses. You can only build detached homes in R3X.

Minimum Lot width =35 Feet

Minimum Lot Area = 3,325 Sq Ft

R3X 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 R3X 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 R3X

The Dwelling Unit factor determines the maximum number of dwellings or families on the property.

1,000 – 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 family homes.

R3X Building Heights: 

Perimeter Wall Height = 21 Feet

Building Height = 35 Feet

Yard Requirements for R3X

Front Yard = 10 Feet minimum

Rear Yard = 30 Feet

Side Yards = 10 Feet each


R3X 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.

R3X Example Lot

Lets assume we have a 40 foot wide and 100 foot deep property in an R3X 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 R3X lot.

Zoning regulates the maximum number of residential units you can put in a building.

Number Of Families = 2

R3X 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.


R3X Zoning in NYC

As an architect I study Zoning Codes closely, but these are complicated and quite involved issues. In this article we reviewed some of the basic concepts with regards to the R3X Zoning Districts. This post does not assume to cover every possible issue or condition, but provide a general overview of the topic.


Thank You for reading our post on R3X Zoning in NYC.

I hope this was helpful. You can leave questions or comments below. If you want to discuss a specific project with an architect you can contact us directly.


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Jorge Fontan

Jorge Fontan

This post was written by Jorge Fontan AIA a Registered Architect and owner of New York City architecture firm Fontan Architecture. Jorge Fontan has earned 3 degrees in the study of architecture including two degrees from the City University of New York and a Masters Degree in Advanced Architectural Design from Columbia University. Jorge has a background in construction and has been practicing architecture for 20 years where he has designed renovations and new developments of various building types.