L Type Staircase with 1 Landing 90
The L stairs has one landing at some point along the flight of steps. If the landing is near the top or bottom of the stairs, the term Long L is used to describe the difference. L stairs are used when the space required for a straight run stairs is not available.
Double L stairs require two 90 degree turns along the flight. They may be used when space is not available for either the straight or L stairs. Double L stairs are not frequently used in residential construction.