In any district, in connection with every building or part thereof hereafter erected having a gross floor area of 10,000 square feet or more, which is to be occupied by manufacturing, storage, warehouse, goods display, retail store, wholesale store, market, hotel, hospital, mortuary, laundry, dry cleaning, or other uses similarly requiring the receipt of distribution by vehicles of material or merchandise, 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 10,000 square feet. Such space may occupy all or any part of any required yard except any part required to be maintained as landscaped open space. Where adjoining an R District, it shall be set back five (5) feet and effectively screen-planted.