(a) "Story" means the portion of a building included between the upper surface of any floor and the upper surface of the floor next above, or if there is no floor above, then the space between the upper surface of the floor and the ceiling or roof above it, or a maximum vertical distance of 13 feet. Exclusions are delineated in the definition of floor area.
(b) Yard Requirements. When related to the number of stories of the building, the required yard shall be the building height divided by the story interval of 13 feet. Fractional remainders, over the last complete story, shall be counted as an additional story. The space below the first finished floor will not be counted as a story, if it is less than four feet above grade, for more than 50% of the total building perimeter.