Precast formwork concrete makes for construction products that are made under controlled conditions and then shipped to construction sites for their use. As they are produced in controlled conditions, they are of a much better quality. Formwork is a significant cost in concrete work, and precast formwork requires a lot of thought to be put into its design so that the repeated use of the formwork will allow such costs to be kept under control.
It requires that the material utilized for this formwork be capable of repeated use, without deteriorating or getting distorted or going out of shape in any way. A lot of thought also has to be given to the de-shuttering process that must be quick, and allow for immediate reuse of the formwork. Materials like rubber and fiberglass allow for easy removal of the molds and are also less liable to get distorted after repeated use.