Abstract: A construction assembly for a prefabricated building, comprises horizontal elements and vertical elements as well as assembly elements. The horizontal, vertical and assembly elements are formed by a first panel forming one of the longitudinal faces, a second panel forming a structuring layer on the opposite longitudinal face, and an insulating layer disposed between the longitudinal faces. The thickness U of the vertical elements corresponds to the cross-section of the assembly elements, the length of the vertical elements is a multiple of U, and at least some of the assembly elements further comprise fluid pipes and/or electrical cabling.