K-Form is a sacrificial screed rail system.  Unlike any other system, its vertical section provides an expansion and contraction facility. This facility is provided by the vertical member being compressible in the same way as conventional joint fillers.

With traditional formwork (lumber or steel), the formwork must be stripped away after each bay has cured and then an expansion filler is put in between each bay. This is usually every 20 feet across the slab. This means that only one bay can be poured before the contractor has to wait for the concrete to cure prior to removing the formwork. With K-Form, the screed rail system stays in place so adjacent bays can be poured on the same day thus many bays are poured at the same time.