Guidelines for Building Inspections: Stair Handrails

Codes

• Until 1994, building inspectors and the housing industry had to consult at least three separate model codes during stair construction. In that year, the nonprofit International Code Council was founded to streamline duplicate and sometimes contradictory regulations through the International Residential Code (IRC). Today, local and state building authorities take their rules from the IRC either verbatim or with minor modifications. (The council also maintains the International Building Code and International Fire Code, among other widely used guidelines.) This enables construction professionals to transfer their code-approved skills anywhere in the U.S.

Basics

• Handrail height is measured from the sloped plane next to the edge of the stair step, or the finished surface of a ramp slope. It must be from 34 to 38 inches high. However, handrails that start over the lowest tread, which are known as volutes, can ignore this height. Rails that provide a continuous transition between flights of stairs, or between handrail or guardrail, can exceed this height. Handrails must be continuous for the full flight of stairs and must be at least 1.5 inches away from any adjacent walls.

Rails

• The total for the handrail height must include the height of the banister or post, plus the thickness of the rail up to its upper surface. Type I handrails have an outside perimeter of under 6.25 inches. If they are circular, the outside diameter must be from 1.25 to 4 inches. If it is not circular, the perimeter dimension must be from 4 to 6.25 inches, with a maximum cross-section of 2.25 inches. Type II handrails, with perimeters of at least 6.25 inches, need graspable finger access areas that are at least 0.3125 inches deep, and start a one-quarter inch as measured vertically from the tallest part of the profile.

Clearance

• Stairways must be at least 36 inches wide measured from the top of the handrail to the minimum headroom above the stair. Handrails cannot project more than 4.5 inches on either side of the stairway. The minimum clear width from below the handrails to the top of the stair step must be at least 31.5 inches for only one handrail, and 27 inches for two handrails.