Abstract: There is described a prefabricated building element which comprises at least one frame and at least one closing panel which extends between the inner edges of said frame, connecting means being provided between the frame and the panel, said means being so arranged as to let the frame and panel move relative to one another, along a direction substantially in parallel relationship with the element thickness, to lie in two end positions, the one position in which the panel is received within the thickness of the frame and the other position in which the panel projects relative so said frame.