Authorized accessory buildings may be erected as a part of the principal building or may be connected to it by a roofed over porch, patio, breezeway or similar structure, or they may be completely detached.  If attached to the principal building, an accessory building shall be made structurally a part of it and shall comply in all respects with the requirements applicable to the principal building.  An accessory building not attached and not made a part of the principal building as provided in the preceding statement shall not be nearer than 10 feet from any other separate structure on the same lot.