CodeMandatory
Garage-to-dwelling door fire rating
IRC R302.5.1Description
Doors between an attached garage and the dwelling must be 1-3/8" solid-wood, solid- or honeycomb-core steel, or 20-minute fire-rated, AND self-closing.
Why this exists
The most critical residential fire-separation detail. Cars store ~20 gallons of gasoline a few feet from sleeping rooms; this door is what buys time.
Measurements
| Property | Operator | Value | Unit | Note |
|---|---|---|---|---|
minDoorThickness | min | 1.375 | in | |
minFireRating | min | 20 | min |
Categories
Life safety
Source
ICCno manifest entry
International Residential Code (2024)
Section: R302.5.1
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.