How High Should I Put My Rail on My Basement Stairs?

Definitions

• Local and state building codes throughout the U.S. are generally based on the International Residential Code, or IRC, which is governed by the International Code Council. This document defines basements as a story that is not a story above ground level. It also defines stairs as a “change in elevation, consisting of one or more raisers” and handrails as “a horizontal or sloping rail intended for grasping by the hand for guidance or support.” While the IRC lists separate measurements and other specifics for basements, stairs and rails, it does not state anything about handrails on basement stairs.

Handrails

• Given the lack of rules for basement stair handrails, construction professionals must rely on the regulations for all stairs when creating these structures. The IRC mandates handrails on at least one side of a flight of stairs with at least four risers. They must be between 34 and 38 inches high, measuring from the stair step or any ramp slope. The height is based on the thickness of the rail itself plus either a baluster or its mounting on an adjacent wall, and the latter is more likely in the case of basement stairs.

Size

• Type I handrails measure less than 6.25 inches, and they are usually round for easier gripping. They must have an outside diameter of between 1.25 to 2 inches. If they are not round, they must have a maximum perimeter of 4 inches, with a maximum cross section of 2.25 inches. Type II handrails are bigger than 6.25 inches. They need a graspable recess area on both sides of the profile. This area must start at 0.75 inches from the tallest part, and continue to at least 1.75 inches below the tallest part. It must be at least 0.31 inches deep, to allow fingers to grab hold.

Exception

• The IRC makes an exception to these rules for special basement stairs called bulkhead enclosure stairways. These constructions extend from the outside ground level, such as a yard or patio, to a lower finished level, such as a basement. Handrail specifications do not apply to these stairways if they meet all three following conditions: The maximum height of the stair from basement to ground level is less than 8 feet. They are not the only way to exit the building. The opening from the ground level to the stairway has a covering such as hinged doors.