2013 California Standards for Accessible Design Pocket Guide

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 (101.6 mm). Changes in height greater than ½ inch (12.7 mm) shall be accomplished by means of a ramp complying with Section 1114A or by means of a platform constructed to the level of the floor as illustrated in Figure 11A-8J.

FIGURE 11A-8J
PLATFORM AT SECONDARY EXTERIOR DOOR