To speed up site production, stair flights can be of precast instead of cast in-situ concrete. Precasting stairs produces better surface finishes, avoids the inherent problems of casting complicated inclined sections on site and provides rapid access to successive floors. They are particularly cost effective when the design of the building requires a reasonable amount of repetition.
Typically two flights of stairs will be used at each storey; the half landing may be cast integrally with the stair units or may be a separate slab, depending on the configuration of the supporting frame. The soffits and sides of the units may be specified to have a finish suitable for direct painting. (Alternatively units may be cast on their side, to give a good finish on both the upper surface and the soffit.)
As an alternative to stair flights, separate tread units may be precast and joined to form a complete staircase (e.g. a spiral staircase).