In all districts except the C-1 Central Business District, in connection with every building or part thereof hereafter erected having a gross floor area of 10,000 square feet or more, there shall be provided and maintained on the same lot with such building at least one off-street 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.
1. Each loading space shall be not less than 10 feet in width and at least 25 feet in length.
2. Where loading spaces adjoin residential districts, they shall be set back five feet and an opaque screen of six feet in height shall be installed and maintained along the interior side yards and rear yards of the abutting residential lots.