Parts of a heavy structure are fabricated in a workshop and transported to erect at site to complete the structure. In this method time and cost is saved as similar construction tasks can be grouped and skilled labour is available at workshop. The method is best suitable for application where the structure is composed of repeating units of same construction practice. Prefabrication avoids the need to transport skilled workers to the construction site. Also the restricting conditions and lack of resources at site are avoided. Transportation costs may be higher for huge prefabricated sections than for their constituent materials, which can often be packed and transported easily. Large prefabricated sections may require heavy cranes and skilled manpower to erect it.

Prefabrication can be used for Bridges, towers, pipe racks, etc.