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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.