In this section
New Hampshire State Building Code: Stairs & Guards
New Hampshire builds to the 2021 IRC statewide, with a 2024 IRC edition due to enter a concurrency window from 1 July 2026 — confirm which edition your building department is currently accepting.
New Hampshire builds to the NH State Building Code — Residential Code for One- and Two-Family Dwellings, based on the 2021 IRC, mandatory statewide since 1 July 2024. A 2024 IRC update was scheduled to take effect 1 July 2026, with a concurrency period running through 31 December 2026 during which either the 2021 or 2024 edition may be used. That window has now opened — confirm with your local building official which edition currently applies before relying on either set of figures.
No confirmed New Hampshire-specific stair or guard amendment surfaced for either edition — figures follow the IRC baseline. See the US stair & guard rules for the shared figures.
Adoption status
Adopted- Current code in force
- NH State Building Code — Residential Code for One- and Two-Family Dwellings (2021 IRC)
- Next edition
- —
- Adoption / transition
- Mandatory statewide; 2021 IRC effective July 1, 2024. A 2024 IRC update is scheduled effective July 1, 2026 with a concurrence period (July 1-Dec 31, 2026) during which either the 2021 or 2024 edition may be used — verify 2024 rollout separately
Last verified 2026-07-28
No state-specific variations recorded yet for this jurisdiction.