Correct Stair Railing Heights

Origins

• Because local and state building authorities throughout the U.S. must serve their constituents, you might expect codes to differ by region. In reality, however, all codes in the country come from the International Residential Code and the International Building Code. Both documents are managed by the International Code Council, a nonprofit organization founded in 1994 to streamline duplicate and conflicting building regulations in the nation. This consistency ensures that the homeowners and construction professionals can expect the same standards no matter the location.

Basics

• The basic rule for stairway handrails is that they must be within the grasp of anybody climbing the steps. This means anyone on any part of this step must be within 30 inches of a handrail, and it must be continuous and uniform throughout an entire flight of steps. A residential staircase up to 36 inches wide needs only one handrail to comply with this code. Wider staircases may need a railing on either side as well as intermediate railings. In any case, handrails cannot project more than 4.5 inches into either side of the stairway. They must still allow a clear width of 31.5 inches on the step for one handrail, and 27 inches for two handrails.

Height

• Stair railings must measure between 34 and 38 inches from the top of the rail up to either the slope plane next to the tread edge, or the finished surface of a ramp slope. The railing can exceed the maximum height at the start of a flight of steps, when transitioning between flights or when moving from a stairway handrail to a balcony guardrail. A turnout or volute at the lowest step can also ignore this height requirement.

Size

• Because stair railing heights are measured from the top of the rail, this component must follow size guidelines. Type I railings with a circular cross section must have a diameter of between 1.25 and 2 inches. If it is not circular, it must have a perimeter dimension between 4 and 6.25 inches, with a maximum cross-section of 2.25 inches. Edges must have a minimum radius of 0.01 inches. Type II railings with a perimeter over 6.25 inches require graspable finger areas on both sides of the profile. These recessed areas must be at least 0.31 inches deep, and start at 0.75 inches from the tallest portion of the profile and continue at least 1.75 inches below the tallest portion.