In making the necessary measurements under this chapter, the Building Inspector, where appropriate, shall include all bays, balconies, garages and porticoes, and all inner, interior, lighted, open and recessed courts, together with all interior and exterior walls. Basements and attics shall be included in square footage areas, except that attics in fourth and seventh grade buildings shall not be included, unless the same are fifty percent or more occupied for billiard, living, toilet or other rooms. When a building is not divided into stories or galleries, each section of twenty feet or fraction thereof shall be deemed a story. This provision shall also apply to roofs, attic spaces, roof appendages above the attic floor line, and all the free- standing towers, elevators, chutes, theaters, halls, etc.
(1974 Code § 155.10)