Stairs

Stairs are a structure designed to bridge a large vertical distance between lower and higher levels by dividing it into smaller vertical distances. This is achieved as a diagonal series of horizontal platforms called steps which enable passage to the other level by stepping from one to another step in turn. The part of the stairway that is stepped on. It is constructed to the same specifications (thickness) as any other flooring. The tread "depth" is measured from the back of one tread to the back of the next. The "width" is measured from one side to the other. Stringer board, stringer, or sometimes just string: The structural member that supports the treads and risers in standard staircases. There are typically three stringers, one on either side and one in the center, with more added as necessary for wider spans. Side stringers are sometimes dadoed to receive risers and treads for increased support. Stringers on open-sided stairs are called "cut stringers".