Rear yards shall be provided in accordance with the regulations hereinafter indicated. Rear yards shall be unobstructed from ground level to the sky, except as allowed in section 5-3-9 of this title. All accessory buildings which are attached to principal buildings (as attached garages) shall comply with the yard requirements of the principal buildings. (Ord. 63-1, 4-1-1963; amd. 1977 Code)