27.04.200 Floor Area.

(a) Definitions.

(1) Floor Area. Floor area means the sum of the gross horizontal areas of all principal and accessory buildings and above grade covered parking on a zoning plot.

(2) Floor Area Ratio (FAR). Floor area ratio means the gross floor area of the buildings on a zoning plot divided by the net lot area.

(b) Measurement, other than single-family dwellings in R1 zoning districts.

(1) Floor area is measured from the exterior façade of the building's wall planes, from the centerline of party walls, or from a line three feet from the edge of an eave, whichever produces the largest floor area. Stories exceeding fifteen (15) feet in height shall be counted as additional floor area, with the exception that ground floor retail may be up to eighteen (18) feet in height measured from first finish floor to second finish floor before being counted as additional floor area. Floor area also includes all accessory structures on the site and basements that meet the definition in subsection (c)(6).

(2) Exclusions. The following are not counted as floor area:

(A) Covered or open courts, and atriums, on the ground floor, provided that the area is not used as dwelling, office, retailing, or required access;

(B) In multiple-level buildings, covered courts, if the retailing uses are open to the public. Multiple-level stairwells and elevators shall be counted only as ground floor area;

(C) Covered walkways and balconies;

(D) First floors, mechanical areas, penthouse, and top floors are counted only once as floor area, regardless of height;

(E) Bicycle parking facilities;

(F) Floor area designated for day care centers accessory to and intended to serve a multi-family, commercial, office or manufacturing use. Such floor area may be located within the primary structure or may be in a freestanding structure accessory to the primary structure;

(G) Covered parking for office use shall not be counted as floor area in areas delineated for exclusion within an adopted plan, such as the Mariner's Island Specific Plan or the Bay Meadows Specific Plan.

(c) Measurement, for single-family dwellings in R1 zoning districts, shall include the following:

(1) A covered structure or portion of a building where it has a horizontal or sloped covering which consists of 50% or more solid material.

(2) All area enclosed within the walls of the principal structure (as measured from the outside perimeter of walls), and the area (or footprint) of any attached carports, covered balconies or porches (as measured from the outside perimeter of its support structures).

(A) Exception: To encourage street frontage activity, the first 100 square feet of a covered front porch shall not be included as floor area.

(3) The area of all detached accessory structures, regardless of the number of open sides, including:

(A) Detached garages and carports;

(B) Storage sheds and other similar structures; and

(C) Covered patios or similar structures.

(4) Any interior space where the vertical distance between the upper surface of the floor and the floor above is fifteen (15) feet or more shall be counted as twice the floor area. If there is no floor above the space, then the distance shall be measured to the underside of the roof structure.

(5) Attic space is considered floor area when area "A" is at least 50% of areas "A" and "B" combined in the following plan-view diagram:

(6) A basement is considered floor area when:

(A) It is habitable space as defined in the current California Building Code, and

(B) More than one-half the area of the outermost basement walls is above finished or pre-existing grade (whichever is lower), and the surface of the finished floor level above is either:

(i) More than four (4) above finished or pre-existing grade (whichever is lower) for more than 50% of the total perimeter, and

(ii) More than twelve (12) feet above finished or pre-existing grade (whichever is lower) at any point.

(d) Off-Street Parking and Loading. Floor area for determining off-street parking and loading requirements as contained in Chapter 27.64, shall be based on physical floor space and shall not include the following:

(1) Storage areas except for areas located within selling or working space such as counters, racks, and closets;

(2) Utility areas including, but not limited to, elevator shafts, telephone switching rooms, stairwells, rest rooms, and heating and cooling rooms;

(3) Accessory facilities to be used only by employees of the principal uses;

(4) Off-street parking and loading facilities, including aisles, ramps, and maneuvering space;

(5) Basement, attic, or mezzanine floor area other than area devoted to retailing activities, to the production of processing of goods, or to business or professional offices;

(6) Floor area designated for day care centers accessory to and intended to serve a multi-family, commercial, office or manufacturing use. Such floor area may be located within the primary structure or may be in a freestanding structure accessory to the primary structure;

(7) Floor Area Computed for Building Volume. Additional parking shall be required in the event of change of excluded floor areas into uses generating parking.

(e) Interpretation. All interpretations of floor area shall be subject to the review and approval of the Zoning Administrator.

(f) No change in the definition or calculation of floor area, except to the extent that the City Council expressly states that the change allows greater floor area, shall be construed to authorize an expansion of the allowable floor area of a building or structure, whether pursuant to Chapter 27.72 or otherwise.