“Attached” means a physical connection of a foundation, wall, or roof between two (2) buildings. If the method by which the buildings are attached includes an above grade wall, or an above grade wall with a roof, or has a common wall, then the attached buildings shall be considered to be a single structure for the purposes of determining site coverage and gross floor area. If the attachment is above grade, does not enclose area and does not include a wall, then the area of attachment shall not be counted for the purposes of determining site coverage. If the attachment is below grade and is not exclusively used for the storage of motor vehicles then the area of the attachment shall be counted for purposes of determining site coverage.