If the stone elements are laid on a flat and smooth surface it is usually to use various types of adhesives based on special hydraulic binders.
To prevent efflorescence of stone on the top of cement mortar sets up a thin layer of lime mortar.
Need to pay attention to the stones' bedding surfaces.
It 's necessary to pay attention to the stones' bedding surfaces.
Never use aggressive products like bleach, detergents, solvents or abrasive sponges.