CodeMandatory
Stairways ≥ 36 in clear width above handrail; ≥ 31½ in with one handrail, ≥ 27 in with two
2025 RCNYS §R318.7.1 Stairway clear widthDescription
Stairway clear width must be at least 36 in above the handrail height. At and below handrail height (including treads + landings), the clear width must be at least 31½ in with one handrail and at least 27 in with handrails on both sides.
Why this exists
Handrails reduce effective width. The 36 in nominal feels generous; with a single handrail you're really working with 31½ in. For comfortable two-way passage, plan 42-44 in nominal width.
Measurements
| Property | Operator | Value | Unit | Note |
|---|---|---|---|---|
aboveHandrail | min | 36 | in | Width above handrail height |
oneHandrail | min | 31.5 | in | Clear width with handrail on one side |
twoHandrails | min | 27 | in | Clear width with handrails on both sides |
Categories
Life safetyCirculationAccessibility
Applies to
- Jurisdiction: New York State
Source
NY Dept of State / ICCno manifest entry
2025 Residential Code of New York State (2025)
Section: R318.7.1 Stairway clear width
Published 2025-07-01 · last verified 2026-05-15
Solver enforcement
Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.
Related directives
- Garage / dwelling fire separation · IRC R302.6
- Habitable space minimum ceiling height · IRC R305.1
- Egress window net opening dimensions · IRC R310.2
- Stair riser, tread, and headroom · IRC R311.7
- Smoke alarms required throughout dwelling · IRC R314
Last reviewed 2026-05-15.