CodeMandatory
Two-family dwelling unit separation
IRC R302.3Description
Two-family dwellings must be separated by 1-hour fire-rated assemblies (walls and floor-ceiling).
Why this exists
Same intent as townhouse separation, scaled to the lower-density two-family case.
Categories
Life safetyStructure
Source
ICCno manifest entry
International Residential Code (2024)
Section: R302.3
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.