/zoning-analysis-nyc

What it does

Type /as:zoning-analysis-nyc with an address, BBL (Borough-Block-Lot), or BIN. The skill resolves the lot from PLUTO and NYC’s original map data, retrieves the Zoning Resolution text in effect on the analysis date, and calculates the envelope controls it can verify — including the edge cases that trip up even experienced professionals. Anything it cannot establish from the original sources is reported as unresolved, not filled in.

Install

Claude Desktop:

1. Open Customize → Browse plugins
2. Click + → Add marketplace from GitHub
3. Enter AlpacaLabsLLC/skills-for-architects
4. Install Architecture Studio

Claude Code (terminal):

claude plugin marketplace add AlpacaLabsLLC/skills-for-architects
claude plugin install as@skills-for-architects

Or symlink just this skill:

git clone https://github.com/AlpacaLabsLLC/skills-for-architects.git
ln -s $(pwd)/skills-for-architects/skills/zoning-analysis-nyc ~/.claude/skills/zoning-analysis-nyc

Usage

/as:zoning-analysis-nyc 250 Hudson St, New York NY

By BBL:

/as:zoning-analysis-nyc 1-00578-0047

What it calculates

• FAR by use type — residential, commercial, community facility
• Height & setback — base height, building height, sky exposure plane
• Yards & coverage — front, side, rear yards, lot coverage
• Permitted uses — by use group
• Parking requirements — under the text in effect on the analysis date
• Bonuses & incentives — Inclusionary Housing, UAP, public plaza
• Development scenarios — on request, labelled as hypothetical

What it handles

• Split zones (lots straddling two or more districts)
• Contextual districts (A/B/D/X suffixes, verified in the Zoning Resolution text)
• Commercial overlays
• Special purpose districts
• Waterfront overlays
• Quality Housing program (optional height factor and base/tower)
• City of Yes for Housing Opportunity provisions (December 2024)

Data sources

• NYC PLUTO dataset (Socrata Open Data API)
• NYC Zoning Resolution
• NYC Department of City Planning
• ZoLa (zola.planning.nyc.gov)

Sample output

Generated from: /as:zoning-analysis-nyc 250 Hudson St, New York NY

# Zoning Analysis — 250 Hudson Street, Manhattan

## Lot Summary

| Parameter | Value |
|-----------|-------|
| BBL | 1-00578-0047 |
| Address | 250 Hudson Street |
| Borough | Manhattan (New York County) |
| ZIP | 10013 |
| Lot Area | 21,862 SF |
| Lot Dimensions | ~170 ft × 130 ft (irregular) |
| Current Building Area | 340,618 SF |
| Current FAR (built) | 15.58 |
| Current Use | Office (Class O6) |
| Year Built | 1929 |
| Last Altered | 2011 |
| Number of Floors | 14 |
| Zoning Map | 12a |

## Zoning Classification

| Parameter | Value |
|-----------|-------|
| Primary District | M1-6 |
| Special District | HSQ (Special Hudson Square District) |
| Commercial Overlay | None |
| Limited Height | None |
| Contextual | Yes (via HSQ — C6-4A equivalent for residential) |
| Split Zone | No |
| Landmark | None |
| Historic District | None |

### Special Hudson Square District (HSQ)

The 2013 Hudson Square rezoning (ZR Article VIII, Chapter 8) overlays M1-6
and permits residential development using C6-4A bulk rules. The district
includes conversion restrictions to preserve commercial floor area in
qualifying buildings (>70,000 SF as of 3/20/2013).

250 Hudson Street is a **qualifying building** (340,618 SF). Residential
conversion requires CPC certification and a restrictive declaration.

## Bulk Parameters

### Floor Area

**For developments containing residences (C6-4A equivalent):**

| Use | Max FAR | Max Floor Area (SF) |
|-----|---------|---------------------|
| Residential | 9.0 | 196,758 SF |
| Commercial | 10.0 | 218,620 SF |
| Community Facility | 10.0 | 218,620 SF |

**For non-residential development (M1-6 base):**

| Use | Max FAR | Max Floor Area (SF) |
|-----|---------|---------------------|
| Commercial | 10.0 | 218,620 SF |
| Community Facility | 10.0 | 218,620 SF |
| Manufacturing | 10.0 | 218,620 SF |

The existing building at 340,618 SF (FAR 15.58) significantly exceeds the
10.0 FAR maximum. This is a pre-existing non-conforming condition —
grandfathered but cannot be enlarged.

### Height & Setback

| Parameter | Value |
|-----------|-------|
| Max Building Height | 290 ft (general) / 430 ft (Subdistrict A) |
| Base Height (min–max) | 60–85 ft (C6-4A, wide street) |
| Sky Exposure Plane | Starts at 85 ft, ratio 5.6:1 (wide street) |
| Street Wall | Required at street line (C6-4A residential) |
| Tapering | Above 230 ft: top 15% — each floor ≤90% of floor below |

### Yards & Coverage

| Parameter | Value |
|-----------|-------|
| Front Yard | None |
| Rear Yard | 20 ft (M1-6) or 30 ft (C6-4A residential) |
| Side Yards | None |
| Max Lot Coverage | No maximum (tower coverage rules apply above base) |

## Permitted Uses

**As M1-6 (non-residential):**
- Commercial: Use Groups 4–14, 16
- Community Facility: Use Groups 3–4
- Manufacturing: Use Groups 16–17
- Residential: NOT permitted under base M1-6

**As HSQ (with residential):**
- Residential: Use Group 2 — permitted via Special District
- Subject to qualifying building conversion restrictions

## Parking Requirements

Post-City of Yes (December 2024):

| Use | Requirement |
|-----|-------------|
| Residential | None (mandate eliminated) |
| Commercial | None (mandate eliminated) |
| Parking maximum | Manhattan Core — capped, not required |
| Loading | ~7 berths (based on ~340,000 SF) |
| Bicycle | 1 per DU (residential); 1 per 2,000 SF (office) |

## Bonuses & Incentives

| Bonus | Details |
|-------|---------|
| Inclusionary Housing | Available — Hudson Square is IH-designated |
| UAP (City of Yes) | +20% residential FAR for affordable housing |
| School exemption | Subdistrict A: school floor space exempt from FAR |

### UAP Calculation

| Scenario | Residential FAR | Floor Area (SF) |
|----------|----------------|-----------------|
| Base | 9.0 | 196,758 SF |
| With UAP (+20%) | 10.8 | 236,110 SF |
| UAP increment (must be affordable) | 1.8 | 39,352 SF |

## Restrictions & Special Conditions

- **Qualifying building:** Residential conversion requires CPC certification
  and restrictive declaration preserving commercial floor area.
- **Non-conforming FAR:** 15.58 built vs. 10.0 allowed. Cannot enlarge.
  Demolish-and-rebuild limited to 10.0 FAR.
- **PFIRM15 flag:** Lot flagged in preliminary flood maps. Verify with FEMA.

## Development Potential

### New Development (demolish and rebuild)

| Scenario | FAR | Floor Area (SF) | Est. Floors |
|----------|-----|------------------|-------------|
| As-of-right commercial | 10.0 | 218,620 SF | ~18 |
| As-of-right residential | 9.0 | 196,758 SF | ~16 |
| Residential with UAP | 10.8 | 236,110 SF | ~20 |
| Residential with IH bonus | Up to 12.0 | Up to 262,344 SF | ~22 |
| Community Facility | 10.0 | 218,620 SF | ~18 |

### Retain Existing Building

- Office (current): 340,618 SF grandfathered. No expansion.
- Residential conversion: CPC certification required. Must preserve
  commercial floor area. Significant constraint.
- Office-to-residential (City of Yes): Eligible (built 1929, before
  1991 cutoff). HSQ qualifying building rules may supersede.

## Buildable Envelope

### Plan View

                        ← 170 ft →
             ┌──────────────────────────────┐
             │         20 ft rear yard      │  ↑
             │  ┌────────────────────────┐  │  |
             │  │                        │  │  |
             │  │    BUILDABLE ZONE      │  │  |
             │  │    170 ft × 110 ft     │  │  130 ft
             │  │    ~18,700 SF          │  │  |
             │  │                        │  │  |
             │  │                        │  │  |
             │  └────────────────────────┘  │  ↓
             └──────────────────────────────┘
                  HUDSON ST (wide street)
                  ← no front setback →

No side yards (not adjacent to R district). Rear yard 20 ft (M1-6)
or 30 ft if residential (C6-4A). Irregular lot — verify with survey.

### Section View (Hudson St)

    290 ft ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ max height (HSQ general)
           │                ╱
           │              ╱  sky exposure
           │            ╱    plane (5.6:1)
           │          ╱
     85 ft ├────────┤ ← setback line
           │        │
           │        │ streetwall / base
           │        │ (60–85 ft)
           │        │
    ───────┴────────┴─────────────────── street
                HUDSON ST (wide)

    Existing: 14 floors (~180 ft), fits within envelope

If in Subdistrict A, max height is 430 ft with tapering (top 15%:
each floor ≤90% of floor below).

## Caveats

- Based on PLUTO v25v4 and ZR as of March 2026.
- PLUTO shows residfar=0 because base M1-6 prohibits residential.
  The HSQ special district overrides this to 9.0 (C6-4A equivalent).
- Subdistrict boundaries should be verified on ZoLa.
- Qualifying building restrictions are legally complex — review
  ZR Section 88-11 with counsel before any conversion project.
- City of Yes provisions are phasing in. Confirm effective dates.
- This is not a substitute for professional zoning analysis or
  legal advice.

> **Disclaimer:** This is an AI-generated analysis for preliminary planning purposes. All findings must be verified by a licensed professional before use in design, permitting, or regulatory submissions.