Accessory buildings shall not be permitted on a parcel prior to the existence of a principal use. The following standards shall apply to all accessory buildings in residential districts:
(1) Roofing materials must be compatible and similar in relation to the primary structure; and
(2) Exterior siding must be compatible and similar in relation to the primary structure.
(3) In no case shall a detached garage have more square footage than the principal building and shall not be higher than the principal building.