Section 1011 — STAIRWAYS
2025 California Building Code (Title 24, Part 2) · 2025 edition · ingested 2026-07-07 · California
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[DSA-AC] In addition to the requirements of this section, means of egress, which provide access to, or egress from, buildings or facilities where accessibility is required for applications listed in Section 1.9.1 regulated by the Division of the State Architect—Access Compliance, shall also comply with Chapter 11A or Chapter 11B, Sections 11B-210 and 11B-504, as applicable.
1011.1 General. ¶
1011.1 General. Stairways serving occupied portions of a building shall comply with the requirements of Sections 1011.2 through 1011.13. Alternating tread devices shall comply with Section 1011.14. Ship’s ladders shall comply with Section 1011.15. Ladders shall comply with Section 1011.16. Exception: Within rooms or spaces used for assembly purposes, stepped aisles shall comply with Section 1030.
1011.2 Width and capacity. ¶
1011.2 Width and capacity. The required capacity of stairways shall be determined as specified in Section 1005.1, but the minimum width shall be not less than 44 inches (1118 mm). The minimum width for stairways that serve as part of the accessible means of egress shall comply with Section 1009.3. Exceptions: 1. Stairways serving an occupant load of less than 50 shall have a width of not less than 36 inches (914 mm). 2. Spiral stairways as provided for in Section 1011.10. 3. Where an incline platform lift or stairway chairlift is installed on stairways serving occupancies in Group R-3, or…
1011.3 Headroom. ¶
1011.3 Headroom. Stairways shall have a headroom clearance of not less than 80 inches (2032 mm) measured vertically from a line connecting the nosings. Such headroom shall be continuous above the stairway to the point where the line intersects the landing below, one tread depth beyond the bottom riser. The minimum clearance shall be maintained the full width of the stairway and landing. Exceptions: 1. Spiral stairways complying with Section 1011.10 are permitted a 78-inch (1981 mm) headroom clearance. on Jul 18, 2025 11:14 AM (CDT) THEREUNDER. MEANS OF EGRESS 2. In Group R-3 occupancies;…
1011.4 Walkline. ¶
1011.4 Walkline. The walkline across winder treads shall be concentric to the direction of travel through the turn and located 12 inches (305 mm) from the side where the winders are narrower. The 12-inch (305 mm) dimension shall be measured from the widest point of the clear stair width at the walking surface of the winder. Where winders are adjacent within the flight, the point of the widest clear stair width of the adjacent winders shall be used.
1011.5 Stair treads and risers. ¶
1011.5 Stair treads and risers. Stair treads and risers shall comply with Sections 1011.5.1 through 1011.5.5.3. 1011.5.1 Dimension reference surfaces. For the purpose of this section, all dimensions are exclusive of carpets, rugs or runners. 1011.5.2 Riser height and tread depth. Stair riser heights shall be 7 inches (178 mm) maximum and 4 inches (102 mm) minimum. The riser height shall be measured vertically between the nosings of adjacent treads or between the stairway landing and the adjacent tread. Rectangular tread depths shall be 11 inches (279 mm) minimum measured horizontally between…
1011.6 Stairway landings. ¶
1011.6 Stairway landings. There shall be a floor or landing at the top and bottom of each stairway. The width of landings, measured perpendicularly to the direction of travel, shall be not less than the width of stairways served. Every landing shall have a minimum depth, measured parallel to the direction of travel, equal to the width of the stairway or 48 inches (1219 mm), whichever is less. Doors opening onto a landing shall not reduce the landing to less than one-half the required width. When fully open, the door shall not project more than 7 inches (178 mm) into the required width of a…
1011.7 Stairway construction. ¶
1011.7 Stairway construction. Stairways shall be built of materials consistent with the types permitted for the type of construction of the building. Exceptions: 1. Wood handrails shall be permitted in all types of construction. 2. Interior exit stairways in accordance with Section 510.2. 1011.7.1 Stairway walking surface. The walking surface of treads and landings of a stairway shall not be sloped steeper than one unit vertical in 48 units horizontal (2-percent slope) in any direction. Stairway treads and landings shall have a solid surface. Finish floor surfaces shall be securely attached.…
1011.8 Vertical rise. ¶
1011.8 Vertical rise. A flight of stairs shall not have a vertical rise greater than 12 feet (3658 mm) between floor levels or landings. Exception: Spiral stairways used as a means of egress from technical production areas. on Jul 18, 2025 11:14 AM (CDT) THEREUNDER. MEANS OF EGRESS
1011.9 Curved stairways. ¶
1011.9 Curved stairways. Curved stairways with winder treads shall have treads and risers in accordance with Section 1011.5 and the smallest radius shall be not less than twice the minimum width or required capacity of the stairway. Exception: The radius restriction shall not apply to curved stairways in Group R-3 and within individual dwelling units in Group R-2.
1011.10 Spiral stairways. ¶
1011.10 Spiral stairways. Spiral stairways are permitted to be used as a component in the means of egress only within dwelling units or from a space not more than 250 square feet (23 m [2] ) in area and serving not more than five occupants, or from technical production areas in accordance with Section 410.5. A spiral stairway shall have a 6 [3] / 4 -inch (171 mm) minimum clear tread depth at a point 12 inches (305 mm) from the narrow edge. The risers shall be sufficient to provide a headroom of 78 inches (1981 mm) minimum, but riser height shall not be more than 9 [1] / 2 inches (241 mm). The…
1011.11 Handrails. ¶
1011.11 Handrails. Flights of stairways shall have handrails on each side and shall comply with Section 1014. Where glass is used to provide the handrail, the handrail shall comply with Section 2407. [DSA-AC] For applications listed in Section 1.9.1 regulated by the Division of the State Architect—Access Compliance, see Chapter 11B, Sections 11B-504.6 and 11B-505. Exceptions: 1. Flights of stairways within dwelling units and flights of spiral stairways are permitted to have a handrail on one side only. 2. Decks, patios and walkways that have a single change in elevation where the landing…
1011.12 Stairway to roof. ¶
1011.12 Stairway to roof. In buildings four or more stories above grade plane, one stairway shall extend to the roof surface unless the roof has a slope steeper than four units vertical in 12 units horizontal (33-percent slope). Exception: Other than where required by Section 1011.12.1, in buildings without an occupiable roof access to the roof from the top story shall be permitted to be by an alternating tread device, a ship’s ladder or a permanent ladder. 1011.12.1 Stairway to elevator equipment. Roofs and penthouses containing elevator equipment that must be accessed for maintenance are…
1011.13 Guards. ¶
1011.13 Guards. Guards shall be provided along stairways and landings where required by Section 1015 and shall be constructed in accordance with Section 1015. Where the roof hatch opening providing the required access is located within 10 feet (3049 mm) of the roof edge, such roof access or roof edge shall be protected by guards installed in accordance with Section 1015.
1011.14 Alternating tread devices. ¶
1011.14 Alternating tread devices. Alternating tread devices are limited to an element of a means of egress in buildings of Groups F, H and S from a mezzanine not more than 250 square feet (23 m [2] ) in area and that serves not more than five occupants; in buildings of Group I-3 from a guard tower, observation station or control room not more than 250 square feet (23 m [2] ) in area and for access to unoccupiable roofs. Alternating tread devices used as a means of egress shall not have a rise greater than 20 feet (6096 mm) between floor levels or landings. 1011.14.1 Handrails of alternating…
1011.15 Ship’s ladders. ¶
1011.15 Ship’s ladders. Ship’s ladders are permitted to be used in lifeguard towers not open to the public and Group I-3 as a component of a means of egress to and from control rooms or elevated facility observation stations not more than 250 square feet (23 m [2] ) with not more than three occupants and for access to unoccupiable roofs. The minimum clear width at and below the handrails shall be 20 inches (508 mm). Ship’s ladders shall be designed for the live loads indicated in Section 1607.10. 1011.15.1 Handrails of ship’s ladders. Handrails shall be provided on both sides of ship’s…
1011.16 Ladders. ¶
1011.16 Ladders. Permanent ladders shall not serve as a part of the means of egress from occupied spaces within a building. Permanent ladders shall be constructed in accordance with Section 304.3 of the California Mechanical Code and designed for the live loads indicated in Section 1607.10. Permanent ladders shall be permitted to provide access to the following areas: 1. Spaces frequented only by personnel for maintenance, repair or monitoring of equipment. 2. Nonoccupiable spaces accessed only by catwalks, crawl spaces, freight elevators or very narrow passageways. 3. Raised areas used…