R4A is a residential zoning district governed by ZR 23-22, with residential far of 1.
These are the figures the engine applies when it models a lot in R4A. Where a rule differs between a narrow and a wide street, both are shown.
| Residential FAR | 1 | ZR 23-22 |
|---|---|---|
| Community facility FAR | 2 | ZR 23-22 |
| Commercial overlay FAR | 2 | ZR 33-121 |
| Front yard | 10 ft | ZR 23-45 |
|---|---|---|
| Side yard | 5 ft | ZR 23-46 |
| Rear yard | 20 ft | ZR 23-47 |
| Lot coverage — interior lot | 60% | |
| Lot coverage — corner lot | 80% |
| Minimum lot area, practical | 1,700 sf | |
|---|---|---|
| Minimum lot width | 25 ft | |
| Parking spaces per dwelling unit | 1 | ZR 25-23 |
At 1 FAR, a 10,000 square foot lot in R4A carries roughly 10,000 square feet of zoning floor area.
That is the ceiling, not the answer. The height envelope, required yards, lot shape, street width, overlays and any special district all cut into it. Running the real lot is the only way to know which constraint binds first.
Every area of the city zoned R4A, from NYC Planning’s published zoning district layer.
The sentences below are quoted verbatim from the Zoning Resolution text the engine is built against, for the R4A rules we have mirrored and checked by hand. Check us against them.
“For all other types of multiple dwelling residences , the applicable dwelling unit factor shall be 680.”
“R4 R4-1 R4A R5 R5A 10 feet”
“R3A R4-1 R4A R4B R5A R5B R5D 2,375 25”
“R3A R4-1 R4A R4B R5A R5B R5D 2,375 25”
“Perimeter walls are subject to setback regulations at a maximum height above the base plane of 25 feet.”
“In R1 through R5 Districts, a rear yard with a minimum depth of five feet shall be provided where such rear lot line coincides with a side lot line of an adjoining zoning lot .”
“These planes start at the maximum permitted height of the perimeter walls and meet at a ridge line of 35 feet above the base plane.”
“In R3, R4 and R5 Districts, the minimum dimension between a legally required window and a side lot line shall be 15 feet.”
Use groups permitted in R4 districts:
Underbuilt here means a lot of at least 2,500 square feet, built to less than half its residential floor area, in private hands, with at least 20,000 square feet of unused capacity. From PLUTO 26v2. How we counted.
R4A has a residential far of 1, set by ZR 23-22. On a 10,000 square foot lot that is about 10,000 square feet of zoning floor area before any bonus, and before the height envelope and yard requirements are applied.
R4A is not governed by a flat height cap in the quality housing tables; height is controlled by the sky exposure plane and the bulk rules shown above.
Source: NYC Planning zoning districts.