The 2024 International Residential Code (IRC) is available. One addition to the new residential code deals with the wood framing around stair openings. This addition was submitted as part of a code change proposal by the Stairbuilders and Manufacturers Association (SMA) based on the work and consensus of an industry committee. MiTek and Simpson Strong-Tie participated in these meetings, along with representatives from the I-Joist industry and others. The SMA position is that the current building code contains a life-safety issue with no language or requirements to ensure adequate guard (stair railing posts) connection points.
Current IRC 2021 Definitions and Sections Dealing with Guards
Definitions:
- Guard: A building component or a system of building components located near the open sides of elevated walking surfaces that minimizes the possibility of a fall from the walking surface to the lower level.
- Handrail: A horizontal or sloping rail intended for grasping by the hand for guidance or support.
Sec. R312.1.2 Height. Required guards at open-sided walking surfaces, including stairs, porches, balconies, or landings, shall not be less than 36 inches in height as measured vertically above the adjacent walking surface or the line connecting the nosing.
From Table R301.5 Minimum Loads, a guard shall be designed to resist a 200-pound load away from the walking surface.
This load and connection have a torsional effect on the framing member, which must be passed through into the floor diaphragm.
This code addition is because stair installers require specific elements within the wood floor system to connect the guards. Currently, stair installers are on the project site after most, if not all, of the finish materials have been installed. Consequently, the stair installers have no information about the wood floor framing at the required guard locations. The stair installers attempt to install the guards, and if it feels as though the fasteners hit solid wood material, they continue with the installation. If the installer feels that the fasteners did not form a solid connection, they will remove the finish materials and install additional wood framing that they believe will be sufficient. The stair installers then repair the finish material and continue the guard installations. None of this work is designed or inspected. It is also highly subjective and dependent on the experience of the stair installers.
SMA is currently working to notify building code officials of this addition to the IRC 2024. It suggests that jurisdictions adopt these new requirements in their current building codes regardless of when they plan to adopt the IRC 2024. Advance adoption of building code provisions is at the discretion of the jurisdiction. SMA has developed a brochure explaining the additions to the IRC 2024 and the details added to the code commentary.
Stair construction has two types of guard connections. The most popular type is the top mount connection, which connects the guard with various methods to the top of the flooring or subfloor. The second type is a side connection, where the guard is notched, slips over the edge of the wood framing, and is connected to the side of the edge member.
Note that these IRC 2024 sections have very specific requirements that must be complied with. The Contractor/Installer/Framer must understand and follow these sections, and the building code official must also fully understand these sections to ensure proper inspection of this framing.
The New IRC 2024 Code Sections
R502.11 Floor framing supporting guards. The framing at the open edge of a floor supporting a required guard assembly shall be constructed in accordance with Sections R502.11.1 or R502.11.2 for guard assemblies not exceeding 44 inches (1118 mm) in height or shall be designed in accordance with accepted engineering practice to support the guard assembly. Where trusses and I-joists are used as edge framing members supporting guards, the effects of the guard loads shall be considered in the design of the edge member.
R502.11.1 Conventional edge framing. Where a roll brace is aligned with each guard post, the framing at the edge of the floor shall consist of a solid or built-up member of lumber, structural glued laminated timber, or structural composite lumber having a minimum net width of 3 inches (76 mm) and a minimum net depth of 9-1/4 inches (235 mm) and shall be braced to resist rotation by roll bracing as described in Section R502.11.3.
R502.11.2 Timber edge framing. Where a roll brace is not aligned with each guard post, the framing at the edge of the floor shall consist of a minimum 6×10 sawn timber or a minimum 5-1/8 × 9-1/4 inch (130 mm x 235 mm) structural glued laminated timber and shall be braced to resist rotation by roll bracing described in Section R502.11.3 at intervals of 48 inches (1219 mm) or less.
R502.11.3 Roll bracing. Each roll brace shall be a joist or blocking matching the depth of the edge member and extending perpendicular to the edge member a minimum of 16 inches (406 mm) from the edge. Blocking shall have end connections for a minimum of 24 inches (610 mm) from the edge and shall be fastened to each roll brace with a minimum of twelve (12) – 10d common nails and shall be fastened to the edge member with a minimum of twelve (12) – 10d common nails within 12 inches (305 mm) of the roll brace.
The details of the IRC 2024 code commentary are as shown in these images from the Early Adoption Handout, “Correcting a Serious Deficit to Building Safety,” courtesy of the Stairbuilders and Manufacturers Association (SMA). [For images, See PDF or View in Full Issue.]
For additional information or if you have any questions, please visit the Stairbuilders and Manufacturers Association website at https://stairways.org/.