CodeMandatory
Stair access from circulation
LS-STAIRS-01Description
Multi-story homes must have stairs accessible from a hallway or open circulation space on every floor, with minimum stair width 36 in.
Why this exists
Stairs must connect through circulation space (hallway / entry / open area), not through bedrooms or bathrooms. Egress from upper floors depends on a clear path down.
Categories
Life safetyEgressCirculation
Source
ICCno manifest entry
International Residential Code (2024)
Section: R311.7
Published 2026-05-09 · last verified 2026-05-09
Solver enforcement
The constraint solver runs check function ls-stairs-01 as a hard constraint — layouts that fail are rejected outright.
Plan symbols this applies to
These plan symbols invoke this directive when placed on a floor plan. Click any to see where it's drawn and what other rules apply to it.
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 2026-05-09.