Before a bond can be formed between the surface of the substrate and the overlay, the substrate must be adequately prepared. It must be capable of withstanding all the forces which are generated by the covering being placed and any loads which may be transmitted to it through the covering. The substrate can be concrete or an overlay. The covering can be an overlay or a polymer in varying layer thicknesses.

The substrate must first be given a defined surface finish before adequate adhesion between covering and substrate is possible. There must be no dirt, grease, or oil and there must be as little cement on the surface as possible. Everyone would be happy if this surface condition could be measured with perfect accuracy. One thesis has already dealt with the question of measuring adhesive tensile strength. The results are somewhat disappointing for practical purposes in the building industry but they nevertheless led to a proposal for standardization at the RILEM¹²⁾. It is also debatable which method of surface treatment is the gentlest. What are the consequences of microscopic cracks which may be caused by this type of treatment?