2013 California Standards for Accessible Design Pocket Guide

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 (25.4 mm), provided a ramp with a maximum slope of 1:8 is permanently installed. (See Figure 11A-8K).

FIGURE 11A-8K
RAMP AT SECONDARY EXTERIOR DOOR