Sky Exposure Plane: What It Is and Where It Still Applies
What is a sky exposure plane in NYC zoning?
A sky exposure plane is an imaginary sloping plane that starts above the street line at a set height and rises over the lot at a set ratio; above the front wall limit, a building must step back and stay under it (ZR 12-10). Typical slopes are 2.7 to 1 on a narrow street and 5.6 to 1 on a wide street, starting at 60 or 85 ft, after a 20 ft or 15 ft initial setback (ZR 23-736, 33-432, 43-43). Since City of Yes it governs commercial and manufacturing buildings and optional sky exposure plane buildings in R6 to R10, not the default residential envelope. Check which envelope applies to your lot, free on Zohgo.
Height factor towers, commercial buildings and factories in NYC are still shaped by a slanted line drawn from the street. Here are the exact slopes and a worked example.
The definition
A "sky exposure plane" (also called a front sky exposure plane) is an imaginary inclined plane that begins above the street line, or where the rules say so, above the front yard line, at a height set in the district regulations, and rises over the zoning lot at a ratio of vertical to horizontal distance also set in the district regulations (ZR 12-10). The "initial setback distance" is the horizontal distance measured from the street line into the lot that the building must step back before it can rise above the front wall limit (ZR 12-10).
In plain terms: up to a certain height the front wall can sit on the street line. Above that height, the building must step back by the initial setback distance and then stay under a slanted line that climbs away from the street. The slope is steeper (more height per foot of setback) on a wide street.
Where it still applies after City of Yes
- Residence districts, by election only: since December 5, 2024, the default R6 to R12 envelope uses base heights, setbacks and fixed maximum heights (ZR 23-432, 23-433). A sky exposure plane governs only "sky exposure plane buildings", an option in R6 to R10 districts without a letter suffix, and not in R6-1, R6-2, R7-3 or R9-1 (ZR 12-10, 23-731, 23-736).
- Community facility buildings in residence districts: in R6 to R12 without a letter suffix, community facility buildings use a sky exposure plane under ZR 24-522.
- Commercial districts: commercial and community facility buildings in C1-6 to C8 districts (ZR 33-432). Residential and mixed buildings in commercial districts follow Article III, Chapters 4 and 5 instead (ZR 33-01).
- Manufacturing districts: all M districts other than those with an A suffix (ZR 43-43).
The numbers: standard front setbacks
| Where | Initial setback (narrow / wide) | Max front wall within it | Plane starts above street line | Slope (narrow / wide) |
|---|---|---|---|---|
| R6, R7 sky exposure plane buildings; community facility buildings in R6, R7 | 20 / 15 ft | 60 ft or six stories, whichever is less | 60 ft | 2.7:1 / 5.6:1 |
| R8, R9, R10 sky exposure plane buildings; community facility buildings in R8 to R12 | 20 / 15 ft | 85 ft or nine stories, whichever is less | 85 ft | 2.7:1 / 5.6:1 |
| C3, C4-1, C8-1 | 20 / 15 ft | 30 ft or two stories | 30 ft | 1:1 / 1:1 |
| C1-6, C2-6, C4-2, C4-3, C4-4, C4-5, C8-2, C8-3 | 20 / 15 ft | 60 ft or four stories | 60 ft | 2.7:1 / 5.6:1 |
| C1-7 to C1-9, C2-7, C2-8, C4-2F, C4-6 to C4-9, C4-11, C4-12, C5, C6, C8-4 | 20 / 15 ft | 85 ft or six stories | 85 ft | 2.7:1 / 5.6:1 |
| M1-1 | 20 / 15 ft | 30 ft or two stories | 30 ft | 1:1 / 1:1 |
| M1-2, M1-4, M2-1, M2-3, M3 | 20 / 15 ft | 60 ft or four stories | 60 ft | 2.7:1 / 5.6:1 |
| M1-3, M1-5, M1-6, M2-2, M2-4 | 20 / 15 ft | 85 ft or six stories | 85 ft | 2.7:1 / 5.6:1 |
Sources: ZR 23-736, 24-522, 33-432, 43-43. Slopes are vertical to horizontal. Note the story counts: the same 60 ft front wall is "or six stories" in residence districts but "or four stories" in commercial and manufacturing districts. Some community facility buildings in C4-1, C8-1 and M1-1 get a 35 ft front wall (ZR 33-432, 43-43).
Zohgo shows the zoning district, FAR, height and setbacks for any NYC address in about a minute. Free to start, sign in with Google or Apple.
Check any NYC address free on ZohgoThe alternate: trade a front open area for a steeper plane
If you leave an open area along the full front lot line, you skip the front wall limit and build under an alternate, steeper sky exposure plane, still measured from a point above the street line.
| Where | Front open area depth (narrow / wide) | Plane starts at | Alternate slope (narrow / wide) |
|---|---|---|---|
| R6, R7 sky exposure plane buildings | 15 / 10 ft | 60 ft | 3.7:1 / 7.6:1 |
| R8, R9, R10 sky exposure plane buildings | 15 / 10 ft | 85 ft | 3.7:1 / 7.6:1 |
| C3, C4-1, C8-1 and M1-1 | 15 / 10 ft | 30 ft | 1.4:1 / 1.4:1 |
| Mid-bulk C and M districts listed above | 15 / 10 ft | 60 ft | 3.7:1 / 7.6:1 |
| High-bulk C and M districts listed above | 15 / 10 ft | 85 ft | 3.7:1 / 7.6:1 |
Sources: ZR 23-736 paragraph (b), 33-442, 43-44. In R9 and R10 the residential alternate does not apply to buildings with more than 25% of their floor area in residential use (ZR 23-736). Towers may penetrate the plane in R9 and R10 under ZR 23-737.
Worked example: how high can you go at a given setback?
An R7 sky exposure plane building. The plane starts 60 ft above the street line. Height of the plane at a distance D from the street line = 60 + D x slope.
| Distance from street line | Narrow street (2.7:1) | Wide street (5.6:1) |
|---|---|---|
| 15 ft | not allowed above 60 ft (inside the 20 ft initial setback) | 60 + 15 x 5.6 = 144 ft |
| 20 ft | 60 + 20 x 2.7 = 114 ft | 60 + 20 x 5.6 = 172 ft |
| 30 ft | 60 + 30 x 2.7 = 141 ft | 60 + 30 x 5.6 = 228 ft |
- Reverse it: to reach a 150 ft roof, the top floor must sit at least (150 - 60) / 2.7 = 33.3 ft back on a narrow street, but only (150 - 60) / 5.6 = 16.1 ft back on a wide street (more than the 15 ft initial setback, so 16.1 ft governs).
- Alternate on the narrow street: with a 15 ft front open area, the alternate plane at 15 ft is 60 + 15 x 3.7 = 115.5 ft, and at 30 ft it is 60 + 30 x 3.7 = 171 ft. On a wide street with a 10 ft open area, it is 60 + 10 x 7.6 = 136 ft at the open area line.
- Commercial comparison: a commercial building in C4-4 on a narrow street can rise at the street line to 60 ft or four stories, whichever is less, then set back 20 ft and follow the same 2.7:1 plane (ZR 33-432).
Floor area still caps the building: the plane is an envelope, not an allowance. Permitted obstructions such as certain bulkheads may penetrate it (ZR 23-41, 33-42, 43-42).
Sky exposure plane FAQ
What is the sky exposure plane slope on a narrow street?
2.7 feet of height for each foot of horizontal distance in R6 to R10 sky exposure plane buildings and most commercial and manufacturing districts, and 1 to 1 in C3, C4-1, C8-1 and M1-1 (ZR 23-736, 33-432, 43-43).
What is the initial setback distance?
20 ft on a narrow street and 15 ft on a wide street in the standard front setback tables (ZR 23-736, 24-522, 33-432, 43-43).
Does the sky exposure plane apply to new apartment buildings?
Only if the building elects the sky exposure plane building option in an R6 to R10 district without a letter suffix (not R6-1, R6-2, R7-3 or R9-1). Otherwise the base, setback and maximum height rules of ZR 23-432 and 23-433 apply (ZR 23-731).
Where does the sky exposure plane start?
Above the street line, at 60 ft in R6 and R7 or 85 ft in R8 to R10 for sky exposure plane buildings, and at 30, 60 or 85 ft in commercial and manufacturing districts depending on the district (ZR 23-736, 33-432, 43-43).
What is the alternate sky exposure plane?
If an open area 15 ft deep on a narrow street or 10 ft on a wide street runs along the full front lot line, a steeper plane applies, typically 3.7 to 1 or 7.6 to 1 (ZR 23-736, 33-442, 43-44).
Can a tower go through the sky exposure plane?
In R9 and R10, towers may penetrate it under ZR 23-737, and commercial and manufacturing districts have their own tower rules (ZR 33-45, 43-45).
Related pages
Sources
Every number on this page comes from the sources below, read 2026-10-27.
- ZR 12-10 definitions: sky exposure plane, initial setback distance, sky exposure plane building: https://zr.planning.nyc.gov/article-i/chapter-2
- ZR 23-731: Sky exposure plane buildings, applicability: https://zr.planning.nyc.gov/article-ii/chapter-3/23-731
- ZR 23-736: Height and setback for sky exposure plane buildings: https://zr.planning.nyc.gov/article-ii/chapter-3/23-736
- ZR 23-737: Tower regulations for sky exposure plane buildings: https://zr.planning.nyc.gov/article-ii/chapter-3/23-737
- ZR 23-432: Height and setback requirements, R6 to R12: https://zr.planning.nyc.gov/article-ii/chapter-3/23-432
- ZR 24-522: Community facility front setbacks: https://zr.planning.nyc.gov/article-ii/chapter-4/24-522
- ZR 33-01: Applicability of commercial bulk chapter: https://zr.planning.nyc.gov/article-iii/chapter-3/33-01
- ZR 33-432: Front setbacks in commercial districts: https://zr.planning.nyc.gov/article-iii/chapter-3/33-432
- ZR 33-442: Alternate front setbacks in commercial districts: https://zr.planning.nyc.gov/article-iii/chapter-3/33-442
- ZR 43-43: Front setbacks in manufacturing districts: https://zr.planning.nyc.gov/article-iv/chapter-3/43-43
- ZR 43-44: Alternate front setbacks in manufacturing districts: https://zr.planning.nyc.gov/article-iv/chapter-3/43-44