Safety with Every Step: Stair Tread Depth vs. Stair Riser Height Table of Contents Building Codes for Stair Tread Depth Building Codes for Stair Riser Height Conclusion Call (513) 889-2492 ORDER NOW Oct 10, 2022 Estimated reading time: 4 minutes Rise and Run for Stairs Following building codes specific to stairs is essential in any new construction or remodeling project to ensure safety for everyone. This article outlines stair code requirements to make it easy for builders to meet relevant regulations and safety standards. Building Codes for Stair Tread Depth The depth of a stair tread is the horizontal distance from the vertical planes of the foremost projection to adjacent stair treads, as seen from a 90-degree angle to the leading edge of a tread. It measures the available surface area for a person’s foot to rest when ascending or descending the stairway. ComplianceStair DepthRiser HeightOSHA9.5″ (240 mm) Minimum9.5″ (240 mm) MaximumIBC11″ (279 mm) Minimum4″ (102 mm) – 7″ (178 mm)Minimum – MaximumIBC Occupancy ExceptionsGroup R-2, R-3, and U (see chart below)10″ (254 mm) Minimum7-3/4″ (197 mm) Maximum Occupancy ClassificationGroupResidential transient – occupancies containing sleeping units where the occupants are primarily transient. Structures like hotels, motels, and boarding housesR-1Residential permanent – occupancies containing sleeping units or more than two dwelling units where the occupants are primarily permanentR-2Residential group – occupancies where the occupants are primarily permanent and not classified as Group R-1, R-2R-3Utility and Miscellaneous – General Buildings and structures of an accessory character and miscellaneous structures not classified in any specific occupancy shall be constructed, equipped, and maintained to conform to the requirements of this code commensurate with the fire and life hazard incidental to their occupancy.U Standard Stair Tread Depth The Industrial Building Code (IBC) and the Occupational Safety and Health Administration (OSHA) have varying tread depth specifications for various stair types. In its 2017 revision to the required walking-working surfaces, OSHA added minimum tread depths. On the other hand, IBC has long mandated a minimum tread depth. OSHA and IBC use research on stairways with varying tread and riser dimensions to determine the minimum tread depths and maximum riser heights. According to OSHA, a standard stair refers to any fixed or permanent stairway aside from alternating tread stairs, ship stairs, or spiral stairs. Standard stairs must, at minimum, maintain a tread depth of 9.5 inches, or 24 cm, under OSHA 1910.25(c)(3). IBC 1011.5.2, on the other hand, stipulates that stair treads must be at least 11 inches (27.94 cm) deep, measured horizontally between the vertical planes of the foremost projection of consecutive treads and perpendicular to the leading edge of the treads. The minimum tread depth must be 10 inches in all group R-3 occupancies, all dwelling units in R-2 occupancies, and all group U occupancies supplementary to either group R-3 occupancies or individual dwelling units in R-2 occupancies. Most multi-family dwellings intended to get occupied permanently must adhere to the standard of a minimum tread depth of 10 inches (25.4 cm). Building Codes for Stair Riser Height The upright (vertical) or inclined element of a stair that gets positioned at the rear of a stair tread or platform and links near the front edge of the next higher tread, platform, or landing is referred to as the stair riser height. Standard Stair Riser Height Depending on the type of stairway, OSHA and IBC also have varying maximum stair riser height regulations. Call (513) 889-2492 ORDER NOW Standard stairs must have a maximum riser height of 9.5 inches (24 cm) following OSHA 1910.25(c)(2). IBC 1011.5.2 stipulates that the minimum and maximum stair riser heights must be 4 inches (10.16 cm) and 7 inches (17.78 cm), respectively. In groups R-3, R-2, and U auxiliary occupancies, the maximum riser height is 7-3/4 inches. Conclusion The purpose of building codes for metal stairs is to ensure the safety of everyone who uses them. Any safety risk will significantly decrease if all steps and stairs have the same tread depth and riser height parameters. For more than 13 years, Upside Innovations has been creating modular metal stairs and platforms. When it comes to design and innovation for a variety of prefabricated metal stair kits as well as custom solutions, Upside Innovations is unmatched in the industry. StairsTools & Resources Types of Stairs for Commercial and Industrial Use Read More » June 7, 2022 StairsTools & Resources IBC Stair Width Calculation Read More » May 6, 2019