There shall be a floor or landing at the top and bottom of each stairway. The width perpendicular to the direction of travel DRAWING 25 shall be not less than the width of the flight served DRAWING 26. For landings of shapes other than square or rectangular the depth at the walk line and the total area shall be not less than that of a quarter circle with a radius equal to the required landing width DRAWING 27. Where the stairway has a straight run, the depth in the direction of travel shall be not less than 36 inches (914 mm).
Exception: A floor or landing is not required at the top of an interior flight of stairs, including stairs in an enclosed garage, provided a door does not swing over the stairs.