Missouri Building Codes: Stairs & Guards

Missouri has no statewide residential building code. Adoption is entirely home rule — cities and counties adopt and amend their own IRC edition, most commonly somewhere in the 2015–2018 IRC range. Kansas City and St. Louis each maintain their own locally amended versions, so the code you build to can differ meaningfully even between neighbouring jurisdictions.

Because there’s no state code to cite, the stair and guard figures here are the plain IRC baseline — 7¾ in max riser, 10 in min tread, 6 ft 8 in headroom, 36 in min width, 34–38 in handrails, 36 in guards, the 30 in guard trigger and the 4 in sphere. See the US stair & guard rules for the shared figures — then confirm the edition and any local amendments with your specific city or county building department, especially in Kansas City or St. Louis where local amendments are known to apply.