R4-1 Zoning NYC

by | Last updated Jun 23, 2020 | Published on Aug 7, 2018 | NYC Zoning

R4-1 Zoning is a residential zoning district in NYC that allows for one family and two family residences only. You can build detached, semi detached, and zero lot line buildings. R4-1 zones often have small homes built individually or in pairs.


R4-1 is a sub district or R4 zoning. Two major differences between R4 and R4-1 is that R4-1 does not allow multi family (3 families or more) and does not allow attached buildings. You can build two houses touching each other, this is called semi detached. You cannot build in groups of more then 2 houses.

R4 Zoning Districts

R4 Contextual Districts



R4-1 Zoning is considered “low density” residential zoning. It typically has 2 or 3 story homes of 1 or 2 families each. When there is a 3rd story it will be within a pitched roof. The pitched roof is very common in R4-1 Zoning because of its zoning requirements and floor area bonus for attic space.



R4-1 Zoning is a residential zone but Community Facility uses are allowed in R4-1 zones. In the instance of a community facility the zoning calculations would be different. One can potentially build a mixed use building with both community facility and residential use.



Lot Size Detached & Zero Lot Line:

A Detached house has yards on all sides. A zero lot line is built on a property line on one side but does not abut another house.

Minimum Lot width =25 Feet

Minimum Lot Area = 2,375 Sq Ft

Lot Size for Semi-Detached:

Semi detached houses are built in pairs they touch in the middle but have yards on the sides.

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 = .75

FAR attic allowance = 20% bonus (.9 FAR total)

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 Heights: 

Perimeter Wall Height = 25 Feet

Building Height = 35 Feet


Front Yard = 10 Feet if greater then 10 it must be at least 18 Feet

Rear Yard = 30 Feet

Side Yards Detached = 8 Feet in total 4 feet each

Side Yards Zero Lot Line = 8 feet One Yard Required

Side Yards Semi Detached = 4 Feet (There are special instances where this can be greater then 4 feet in R4-1 Zoning)


1 Parking Space must be provided for each dwelling unit.



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.


Lets assume we have a 40 foot wide and 100 foot deep property in an R4-1 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.



Lot Area and Width

If we want to do a lot subdivision we will need to examine the lot size. The minimum lot width for a detached home is 25 feet. We started with a 40 foot lot so we cannot divide this into 2 detached lots. The minimum size for a semi detached would be 18 feet. In this case we are good. We can make 2 lots 20 feet wide and 2,000 square feet. The 2,000 square feet exceed the minimum lot area of 1,700 square feet. The zoning calculations below will be for 1 of the properties.

Zoning Floor Area/ Floor Area Ratio (FAR)

So the floor area ratio is .75. 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 .75

Each new lot Size is 20 feet x 100 feet.

Zoning Floor Area = Lot Area X FAR

Lot Area = 20 x 100

Lot Area = 2,000 sq ft

FAR = .75 or

Zoning Floor Area = 4,000 sq ft x .75

Zoning Floor Area = 1,500 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. In this case we can maximize it because this is based on a real project of ours.

Zoning Floor Area with Bonus 1,800 sq ft

So we can build a 1,800 sq ft for each house.


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

Maximum Number Of families = We can build 2 two family houses resulting in a total of 4 families.


R4-1 Zoning Subdivision

Diagram of a lot subdivision for this R4-1 Property in Queens



In this example we are proposing to subdivide the lot into 2 lots of 2,000 square feet each. We will be building one semi detached house on each lot. The two houses will be abutting in the middle with side yards on the outsides. We can have 2 families in each house for a total of 4 families. We will need to provide parking for every family.


R4-1 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 R4-1 Zoning Districts. This post does not assume to cover every possible issue or condition, but provide a general overview of the topic.



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.


Contact Fontan Architecture


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 15 years where he has designed renovations and new developments of various building types.

  • Minhaz, if you would like to discuss this, please call my office at (212) 321-0194.

  • Philip Ambrosino says:

    My house is on a double lot The address is. 5912 71st street Maspeth 11378. It on Realtor.com can I build on the back lot?

  • Carmen Loo says:

    Hi Jorge I am looking to buy 2 lots that are adjacent to eachother where 1 of them is 20*100 and the other is 25×100. The 25×100 is a corner lot. Both are R4-1 zoning.

    Would i be able to build a 4 family semi detached house on the property where 2 family is on each lot?

    Is wood frame construction be allowed for this type of development or I would def need to stick with concrete and steel?

    Thank you.

  • John Hurtado says:

    Hello, I noticed your study didn’t have a set back on the second floor. I would like to know why? or why some homes in R4-1 are required to have a a smaller second floor. Thanks in advance.

  • Ricky Zheng says:

    Instead of the 4 family, but two single family semi-detached, you can put the parking in the front so the building can be a little bit wider? Also the “1 Parking Space must be provided for each dwelling unit”, doesn’t that need to be a garage?

  • Rich Quin says:

    I have a 1 story ranch house at a zero lot line on the right side of my house (neighbor’s house at right side is 3′ from my lot line) and I am sharing an 8′ driveway to my back yard with my neighbor on the left side of my house (4′ of this 8′ driveway is mine and the other 4′ is from my left side neighbor). I plan to add another floor and maximize the FAR allowed for R4-1. A semi detached will be in my favor since I mention 4′ above as one of my side yard but what I have is zero lot line which require 8′ on one yard as per regulations (Side Yards Zero Lot Line = 8 feet One Yard VS. Required Side Yards Semi Detached = 4 Feet ). Is there a design to my house to be considered as semi detached and not a house on a zero lot line to limit my side yard to 4′ in lieu of 8′? What is your advise to maximize my FAR? I am on an irregular lot (trapezoidal) with 37.5 frontage, 13′ rear lot width and 100′ depth. My current house is 19’W x 40’L with cellar. My house is 10′ from the front and almost 50′ from the back.

    • If you’re on the property line and not touching another building, then you have zero lot line. If you are touching another building, then you are touching another lot. From what you describe, it sounds like you have a zero lot line. I would have to review the survey and do a zoning analysis to figure out if there would be anything that could help.

  • Tony jaswal says:

    Hi ,
    But you can build on corner lot 60 feet by 90 feet on corner lot in R4-1 in richmondhill queens. Thanks

  • Andy says:

    Jorge, with a 20′ lot. minus 8′ driveway. you are left with 12′ wide house. its not feasible.

    • Andy,
      I built a house in R4-1 that was 14 feet wide in the front and 12 feet wide in the back so it is feasible. It is not ideal, it is not great but it is possible. If you feel it is an undo burden you can apply for a zoning variance. Also do you need to put the driveway on the side why not put a garage and forget the driveway. I also do not know if you are talking about a semidetached, detached, or zero lot line house house.

  • M Saidi says:

    Where was the parking provided

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