Commission clarifies definitions: building footprint, ground floor level, Highlands and lot-coverage calculations

Planning staff presented a set of definitional amendments intended to remove ambiguity about how several measurement rules are applied across the code, particularly in the R20 overlay district.

Staff proposed adding a definition of building footprint as "the area of the building measured from the exterior walls at grade" and clarified that, when a building is elevated, portions below the elevated structure count as if at ground level. The draft also clarifies building height measurement methods (average between eaves and highest ridgeline for roof structures) and ties ground-floor-level measurements in the R20 overlay to the 2021 Base Building Height Elevation (BBHE) established with the newer flood maps.

On Highlands and lot coverage, staff explained the change distinguishes marsh-front properties (using a critical line) from oceanfront lots (using the jurisdictional baseline) so that undevelopable areas below those lines are not included in the Highlands denominator when calculating lot coverage percentage. Commissioner 4 proposed language defining lot coverage as "the total area of the Highlands that is impervious to stormwater, including buildings, decks, walls, driveways, parking, walkways, and other impervious surfaces" and adding a separate definition for "lot coverage percentage" using the equation in the draft (total impervious coverage divided by total Highlands). Commissioners and staff agreed to retain the term 'impervious' rather than substituting 'improvement.'

Separately, staff reviewed R20 massing and height clarifications that codify the "tiered" or "wedding-cake" character (second-story area limited to 80% of first-story footprint; 0.5 story limited to 50% of the story below) and noted maximum heights remain district-specific (standard 40-foot maximum in many residential zones; 35-foot maximum for patio lots in the R20 overlay). The commission approved the amended language and asked staff to ensure graphics and table labels are consistent with the text before final adoption.