CodeMandatory
Floor elevation at doors
IRC R311.3Description
The floor on each side of an egress door must be ≤1-1/2" lower than the threshold (or ≤7-3/4" with a landing).
Why this exists
Big step-ups at doors trip people. The threshold rule keeps egress paths walkable.
Categories
Life safetyEgress
Source
ICCno manifest entry
International Residential Code (2024)
Section: R311.3
Published 2024-01-01 · last verified 2026-05-09
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 2026-05-09.