the ceramic tiles with which it is used during the installation process inserting the spacer into the joint space in contact with the underlying surface or tamping it into the joint space insures that its upper surface will be below the surface of the grout in the joint space as a consequence of the spacer 39 s open construction during the grouting process the grout slurry flows into the interior cavities of the spacer and hardens and cures there at the same time as the grout hardens and cures in the remainder of the joint spaces the grout within the spacer cavities thus becomes an integral part of the grout mass surrounding the spacer and what little if any resilience is retained by the fully encapsulated spacer material has no affect on the joint it will be noted further that in the solid prior art spacer depicted in fig2 the side walls of the limbs 27 are parallel through their entire lengths and meet at right angles at their respective intersections this construction is permissible because the relatively small deformation of the portion of the sides adjacent the intersections has little effect on the overall width or linearity of the solid limbs 27 the thin walled construction of the limbs 27 in the subject invention however is less forgiving accordingly as.