Full Text
Construction Tip Sheet 01 March 15, 2024 MyBuildingPermit.com I Basic Stairs 1 Basic Stairs This tip sheet reflects code requirements of the 2021 International Residential Code (IRC) with Washington State Amendments. Figure 1: Typical Stair Treads and Risers Stair Treads and Risers â–¡ The largest tread or riser within any flight of stairs is not to exceed the smallest by more than 3/8 inches. (R311.7.5.1) Illumination â–¡ Interior stairways shall be provided with an artificial light source to illuminate the landings and treads. There shall be a wall switch at each floor level to control the light source where the stairway has 6 or more risers. (R303.7) â–¡ Exterior stairways shall be provided with an artificial light source located at the top landing of the stairway and located at the bottom landing where accessing a basement. Stairway illumination shall receive primary power from the building wiring. (R303.8) Handrails â–¡ Handrails are required on at least one side for stairways with four or more risers. See Tip Sheet 2 for additional information regarding handrails. (R311.7.8) 2018 ---PAGE BREAK--- Construction Tip Sheet 01 March 15, 2024 MyBuildingPermit.com I Basic Stairs 2 Landings â–¡ Landings are required at the top and the bottom of stairways. A floor landing is not required at the top of an interior flight of stairs, including stairs in an enclosed garage, provided a door does not swing over the stairs. (R311.7.6) â–¡ A landing extending the width of the stairs and measuring a minimum of 36 inches in the direction of travel is required at the top and bottom of every stairway. (R311.7.6) Circular, Winding, or Spiral Stairways â–¡ For exceptions related to the construction of circular, winding, or spiral stairways, see IRC R311.7.5.2.1 and R311.7.10. Figure 2: Typical Stair Elevation ---PAGE BREAK--- Construction Tip Sheet 01 March 15, 2024 MyBuildingPermit.com I Basic Stairs 3 Figure 3: Headroom Clearance Requirements