Building codes maintain stairways protected with rules that are pertinent to the elevation and depth of every step, support and handrails. Building code enforcement employees take stairway building codes severely, because a small error might lead to serious harm. The International Building Code provides for step and stairway rules in chapter 10 of this IBC code publication. California’s building code is adopted from and closely mirrors the IBC; local ordinances may change or change the code to match local requirements and practices.
Encountering a step that’s a substantially different height, width or depth than other measures on a stairway may upset the climber’s equilibrium, causing a fall. Step building codes are based on the fact that people using stairways expect every step to be the same height. Stairway building codes maintain stairways safer by making sure people using stairs do not encounter the unforeseen.
Treads are the component. They encourage the weight of the consumer. The depth of all of the treads on a staircase must be the same from front to rear, using a maximum variation of 0.375 inches between the deepest and shallowest treads. Treads shall be a minimum depth of 11 inches. Depth is measured from the front and rear edges of the adjacent treads.
A step riser is the space from the top of one step to the top of the following step, measured vertically. Risers need to have a maximum variance of 0.375 inches between the lowest and highest risers on the staircase. Risers need a maximum height of seven inches and a minimum height of four inches. Single-family homes and townhouses are permitted to have a maximum riser height of 7.75 inches.
A single step within a residential home such as a detached house, townhouse or residential condo does not expect a handrail. Stairways of more than a single step within or attached to these structures must have a handrail along either or both sides of the stairway. Two are permitted, although 1 handrail is required.
Stairways must be a minimum of 36 inches wide and have a headroom minimum of 80 inches across the full path of the stairs and one tread length past the bottom step. Headroom is a vertical measurement from the front edge of the tread to the ceiling above. Every stairway is required to have a landing using a length equal to the width of the stair, but landing spans over 48 inches are not required. Stairs with a complete vertical rise of more than 12 feet must have a landing between the upper and bottom landings.
Spiral and round steps and staircases have special codes which apply only to them, as specified by IBC segments 1009.7, 1009.8 and 1009.9. Additionally, there are switching tread apparatus are also permitted in special conditions, as provided for in part 1009.10.