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California Residential Code: Stairs & the 42-inch Guard
California's stair geometry matches the IRC, but it demands taller 42-inch guards — the signature CRC amendment. Here's what applies under the 2025 CRC.
California runs its own California Residential Code (CRC) — Title 24, Part 2.5 — an IRC-based code with California amendments. The current edition is the 2025 CRC (based on the IRC 2024), in force since 1 January 2026.
For a house stair, the geometry matches the IRC — 7¾ in max riser, 10 in min tread, 6 ft 8 in headroom, 36 in min width, 34–38 in handrails. The one figure California changes is the guard height:
| Figure | California | IRC |
|---|---|---|
| Guard height | 42 in (1067 mm) | 36 in |
That taller guard is the classic California amendment. (Where a stair guard’s top rail also serves as the handrail on the open side of stairs, it may sit 34–38 in — same as the IRC.) The 30 in guard trigger and the 4 in sphere match the IRC. See the US stair & guard rules for the shared figures, and confirm against the current 2025 CRC (guards moved to R321).
Adoption status
Adopted- Current code in force
- California Residential Code (2025)
- Next edition
- —
- Adoption / transition
- California uses the California Residential Code (2025 CRC, based on IRC 2024), in force since 1 January 2026. Stair geometry matches the IRC, but California requires taller 42-inch (1067 mm) guards.
Last verified 2026-07-28
State variations
- R312
California requires guards at least 42 in (1067 mm) high — taller than the IRC's 36 in. Stair geometry (riser, tread, headroom) otherwise matches the IRC.
Guides for this jurisdiction
- California Guard Height: 42 Inches Under the CRC
On decks, porches and landings California wants guards at least 42 inches tall, six inches more than the model IRC. Here are the rules and the stair exceptions.