In connection with every building and part thereof erected having a gross floor area of 10,000 square feet or more and which is to be occupied by manufacturing, storage, warehouse, goods display, retail store, wholesale store, market, hotel, hospital or other similar use, there shall be provided and maintained on the same lot with such building at least one off-street loading space, plus one additional such loading space for each 20,000 square feet or major fraction thereof of gross floor area so used in excess of the first 10,000 square feet. Buildings smaller than 10,000 square feet so used may be required to provide loading areas, depending on the type of delivery. Each loading space shall not be less than 10 feet in width, 45 feet in length and 14 feet in clear height. Such space may occupy all of any part of any required yard or court space, except a front yard or the required side yard on the side street of the corner lot. No such space shall be located closer than 30 feet to any lot located in any R District, unless the loading space is wholly within a completely enclosed building.