Abstract: Building block system, magnetically held together, comprising a base plate (1) and at least one building block (2). The base plate (1) comprises a magnetizable metal core (3) and at least one building block (2) comprises at least one magnetizable metallic joining element (4) placed inside the building block. The metal core (3) of the building block system is preferably electrically magnetizable and the parts of the system have smooth surfaces.
Abstract: The specification relates to an arrangement in an intermediate floor or the base floor of a building, producing a duct system for electrical or HEPAC installations. At the end of the cored slabs (1) there is produced, by means of a supporting component (3), a transverse duct which communicates with the cores (6) of the cored slabs. The duct may also be formed by means of a channel beam which adjoins the end surfaces (5) and has openings in alignment with the cores (6). The transverse duct is preferably covered with a separate cover (4).