CodeMandatory
Exterior wall fire separation distance
IRC R302.1Description
Exterior walls within 5 feet of a property line must be 1-hour fire-resistance-rated. Openings in walls within 3 feet are prohibited; openings 3-5 feet must be fire-rated.
Why this exists
Adjacent dwellings need a fire-rated separation to slow fire spread between properties.
Measurements
| Property | Operator | Value | Unit | Note |
|---|---|---|---|---|
minFireResistanceDistance | min | 5 | ft | Distance below which 1-hr rating required |
minOpeningSetback | min | 3 | ft | Min distance to nearest opening |
Categories
Life safetyStructure
Source
ICCno manifest entry
International Residential Code (2024)
Section: R302.1
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.