Primer prior to tiling or painting Suitable on Absorbent surfaces Can be used over underfloor heating Single Coat Application A tile primer is essentially a liquid product, that can be either latex, epoxy or polyurethane based, and is used to create better adhesion onto the substrate before tiling or screeding starts on your tiling project. The function of a primer is to prepare the surface for tiling and increase the bond of the adhesive, screed and waterproofing compounds onto the surface.