hook at the upper edge 7 in a zone set back from the surface 4 the head 14 of the securing means becomes invisible as a result of the lower edge of the adjacent facing placed above when the lower facing has been correctly placed in position for instance by means of several screws 13 in its zone 7 the immediately adjacent upper facing can then be installed the installation is effected for instance at the level of the joint 12 by an interlock on the top edge 5 which will be set back it will be seen in fig4 how the upper adjacent component is fitted by engaging the tongue 9 in the groove 8 this engaging along the whole of the length of the facing represents an interlock which allows two adjacent facings to be connected and also allows the connecting means 13 to be concealed this interlocking allows a good adjustment of the flatness of the facing and the reduction of defects in the support 10 the securing means to the wall on the facing top edge as well as the groove on the top edge which operates in conjunction with the tongue of the lower edge of the adjacent facing allows securing means.