an apparatus for molding a continuous foamed plastic element , such as a floor element having a substantially parallelepipedic central body and at least one side lug , includes a mold in which respective molding cavities of the central body and of the side lug are defined between a bottom wall , a pair of opposite side walls and a cover . a mechanism adjustably positions at least one of the cover and one or both of the side walls of the mold , away from and towards the bottom wall , to regulate , in an adjustable and substantially continuous manner , the height of the molding cavities for at least one of the central body and the at least one side lug of the continuous element .