Straight run stairs: most common type of stair, there less expensive to build, but require a long open space
L-stairs: has one turn ( 90 degrees), has only one landing, used when theres not enough space for straight run stairs.
Double L-stairs: Has two landings and two turns, expensive to build, and they break up the floor plan.
U-stairs: Flights are parallel (180 degrees), only one landing, and there are three types of U-stairs ( open, closed, and boxed)
Winder stairs: No landing during run, pie shaped steps, not very safe because of the steps shape.
Spiral stairs: used when little space is available, gaining in popularity, not safe also because of the step shape.
Circular stairs: Irregular curve, trapiziod shaped steps, and expensive to build.
