Prefabrication of concrete structures is an industrialized process with a large potential for the future. It is often considered by uninitiated designers as a variant execution technique of cast in-situ construction, where the notion of prefabrication means that parts of the construc- tion are precast in specialised plants, to be assembled afterwards on site in such a way that the initial concept of cast in-situ structures is obtained again. This viewpoint is false. Every construction system has its own characteristics which, to a greater or lesser extent, influence the structural lay-out, span and width, stability system, etc. For the best results, a design should respect the specific and particular demands of the intended structure from the very outset of the project.