TILEFILL joints between tiles and natural stone covering are almost exclusively filled with mineral joint mortars nowdays. Joint mortars play an important role in rendering the wall or floor coverings asethetically pleasing as well as ensuring that it functions properly. To satisfy the high technical demands on these products pratice to modify these mortars with speial aeeitive/s. These special additives make the mortar adhere etter to the joint flanks, significantly enhances abrasion resistance and, by sinking the elestric modulus or increasing the plasticity, reduces the tendency to crack. The use of special hydrophic additive/s also greatly lower water absorption by these mortars and hence their tendency to pik up dirt and to effloresce.