A Building is considered any structure having a roof supported by columns or walls.

Planning Department and Assessor's office divide a building into different type of spaces based on the their use. As opposed to General Contractors who give you a cost estimate calculated for ALL the areas in the building, regardless if they're or not usable.  

Gross Area of a building.

A building Total Gross Floor Area is the sum of the gross areas of the several floors of a building or buildings, measured from the exterior faces of exterior walls or from the centerlines of walls separating two buildings.

Gross Floor Area of a building may include:

(1)   Basement and cellar space, including tenants' storage areas and all other spaces except that used only for storage or services necessary to the operation or maintenance of the building itself;

(2)   Elevator shafts, stairwells, exit enclosures, and smoke-proof enclosures at each floor;

(3)   Floor space in penthouses except as specifically excluded in this definition;

(4)   Attic space (whether or not a floor has been laid) capable of being made into habitable space;

(5)   Floor space in balconies or mezzanines in the interior of the building;

(6)   Floor space in open or roofed porches, arcades, or exterior balconies, if such porch, arcade, or balcony is located above the ground floor or first floor of occupancy above basement or garage and is used as the primary access to the interior space it serves;

(7)   Floor space in accessory buildings; and

(8)   Any floor area dedicated to accessory or non-accessory parking, except for bicycle parking, required off-street loading, and accessory parking

Gross Floor Area of a building may NOT include:

(1)   Basement and cellar space used only for storage or services necessary to the operation or maintenance of the building itself;

(2)   Attic space not capable of being made into habitable space;

(3)   Elevator or stair penthouses, accessory water tanks or cooling towers, and other mechanical equipment, appurtenances, and areas necessary to the operation or maintenance of the building itself, if located at the top of the building or separated therefrom only by other space not included in the gross floor area;

(4)   Mechanical equipment, appurtenances, and areas necessary to the operation or maintenance of the building itself;

(5)   Outside stairs to the first floor of occupancy at the face of the building which the stairs serve, or fire escapes;

(6)   Floor space dedicated to accessory parking that does not exceed the amount principally permitted as accessory, and is located on any Basement Story;

(7)   Floor space dedicated to parking which does not exceed the amount principally permitted as accessory, and is located underground;

(8)   Bicycle parking;

(9)   Arcades, plazas, walkways, porches, breezeways, porticos and similar features (whether roofed or not), at or near street level, accessible to the general public and not substantially enclosed by exterior walls; and accessways to public transit lines, if open for use by the general public; all exclusive of areas devoted to sales, service, display, and other activities other than movement of persons;

(10)   Balconies, porches, roof decks, terraces, courts and similar features, except those used for primary access

These are just few examples of areas that could be or not included in the Gross Floor Area. A complete list could be found in the Planning Code.

See other types of Floor Areas in the next article...