Winder stairs have “pie-shaped” steps which are substituted for a landing. This type is used when the space is not sufficient for the L stairs. If winder stairs are used, the width of the triangular steps should be sufficient at midpoint to provide a tread width equal to the regular steps.
Spiral or circular stairs
These stairs are gaining in popularity and the components are now manufactured by several companies. They may be used where little space is available. Most spiral stairs are made from steel and welded together, however, it is possible to construct them from wood.