Buildings of the fifth grade are garages and accessory buildings incident to a main zoning use. Such garages and accessory buildings shall include garages, public or private buildings or enclosures for boarding and keeping of animals or fowl, barns, carriage houses, buses, boiler rooms, storage sheds and any building used as an accessory building incident to the main use of the premises as defined in the Zoning Code.
(1974 Code § 155.07)