509 West 27 Street, Manhattan 10001 is a 4,938 square foot lot zoned C6-3. RunEnvelope’s engine finds an as-of-right scheme with homes of 44,541 sf (UAP (City of Yes)), against 5,395 sf built on the lot today.
That leaves 39,146 sf more floor area than stands here now, if the existing building were replaced. The largest scheme with homes and no affordability obligation holds 37,134 sf (Max Residential (Sky Exposure Plane)).
City Planning’s PLUTO file lists a residential FAR of 7.52 for this lot, which at 4,938 sf of land is 37,134 sf. The engine’s largest residential-only scheme without an affordability obligation (Max Residential (Sky Exposure Plane)) holds 37,134 sf, close to that simple multiplication.
The largest 6 as-of-right schemes RunEnvelope’s engine produced for this lot, by zoning floor area. A full study also models the building itself: floor plates, heights, setbacks, unit mix and parking.
| Scheme | Type | Floor area | FAR | Homes |
|---|---|---|---|---|
| UAP (City of Yes) | Income-restricted housing | 44,541 | 9.02 | 48 |
| AIRS Senior Housing (100% Affordable) | Income-restricted housing | 44,541 | 9.02 | 48 |
| Max Residential (Sky Exposure Plane) | Housing | 37,134 | 7.52 | 41 |
| Commercial Overlay | Mixed use with homes | 37,035 | 7.50 | 36 |
| Community Facility | Community facility | 37,035 | 7.50 | None |
| Existing Building: Retain & Enlarge (ZR 54-31) | Keeps existing building | 37,035 | 7.50 | None |
Floor area is zoning floor area in square feet. Highlighted: the largest scheme with homes. Income-restricted schemes (Universal Affordability Preference, AIRS senior housing) require a share or all of the homes to be affordable. Shared housing counts rooms, not apartments. Schemes that need a landmark transfer of development rights, the FRESH food store bonus or a stack of every program are left off this page; the full study shows them.
As-of-right only: what the Zoning Resolution allows without a variance, special permit or rezoning. Computed by RunEnvelope’s zoning engine on October 21, 2026 from PLUTO 26v2 lot data, in screening mode: the engine uses the City’s recorded lot area and dimensions, not a surveyed lot outline.
This is not a professional opinion, an appraisal or a statement that anything will or should be built here. Existing tenants, leases and the owner’s plans are not part of it.
Why this lot has a page: we publish pages only for lots that clear a set of data quality and headroom tests.
The closest published lots in Manhattan, same zoning district first. All Manhattan lots.