2025 California Standards for Accessible Design Guide (effective January 1, 2026)

11B-809.8.3.1 Floor or ground surface.

Floor or ground surface within required maneuvering clearances shall not have slopes exceeding 1:48.

Exceptions: The floor or landing at primary entry doors, required exit doors and secondary exit doors where a change in elevation
occurs between the interior and the exterior surface of the floor or landing, shall comply with the following:

1. Exterior landings of impervious construction (e.g., concrete, brick, flagstone) serving primary entry doors and required exit doors are limited to not more than 1/2 inch (12.7 mm) of change in height between floor surfaces. Changes in level shall comply with Section 11B-809.7.2.
2. Exterior landings of pervious construction (e.g., wood decking with spaces) shall be the same level as the interior landing, except that secondary exterior doors may have no more than 1/2 inch (12.7 mm) of change in height between floor surfaces. Changes in level shall comply with Section 11B-809.7.2.
3. Secondary exterior doors onto decks, patios or balcony surfaces constructed of impervious materials (e.g., concrete, brick, flagstone) may have a maximum change in height from the interior landing of 4 inches (102 mm). Changes in height greater than 1/2 inch (12.7 mm) shall be accomplished by means of a ramp complying with Section 11B-405 or by means of a platform constructed to the level of the floor as illustrated in Figure 11B-809.8.3.1(3).
4. Secondary exterior doors onto decks, patios or balcony surfaces constructed of impervious materials (e.g., concrete,
   brick, flagstone) may have a maximum change in height from the interior landing of 1 inch (25 mm), provided a ramp
   with a maximum slope of 1:8 is permanently installed as illustrated in Figure 11B-809.8.3.1(4).