Stair handrail and guard rules — heights and the sphere-opening limits

Handrail 34–38″ above the nosings; guard ≥36″ at landings and open sides. Infill blocks a 4″ ball — 4⅜″ on the open stair itself, 6″ in the tread-riser-rail triangle. — IRC R311.7.8 & R312

An elevation of a stair meeting a landing, showing the two safety rails and their code limits. A graspable handrail runs 34 to 38 inches measured vertically above the tread nosings along the flight. A guard at least 36 inches high protects the open side of the stair and the landing edge. The infill openings are limited by sphere rules: a 4-inch sphere cannot pass through a guard, a 4 and 3-eighths inch sphere cannot pass through the open side of the stair itself, and a 6-inch sphere cannot pass through the triangle formed by the tread, riser, and bottom rail. Heights and openings follow IRC R311.7.8 for handrails and R312 for guards. — Source: IRC R311.7.8 (handrail height/grip), R312.1 (guard height & sphere rules)

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An elevation of a stair meeting a landing, showing the two safety rails and their code limits. A graspable handrail runs 34 to 38 inches measured vertically above the tread nosings along the flight. A guard at least 36 inches high protects the open side of the stair and the landing edge. The infill openings are limited by sphere rules: a 4-inch sphere cannot pass through a guard, a 4 and 3-eighths inch sphere cannot pass through the open side of the stair itself, and a 6-inch sphere cannot pass through the triangle formed by the tread, riser, and bottom rail. Heights and openings follow IRC R311.7.8 for handrails and R312 for guards.

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    Diagram: <a href="https://remodelcalculators.com/construction-diagrams/stair-guard-handrail" target="_blank" rel="noopener">Stair handrail and guard rules — heights and the sphere-opening limits</a> — courtesy of <a href="https://remodelcalculators.com" target="_blank" rel="noopener">RemodelCalculators.com</a>
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