A single-component, solvent-based, water-free polyurethane coating for interior use. It is used for strengthening mineral substrates and improving adhesion before bonding parquet with polyurethane adhesive BK-ParketFix PU. The substrate moisture content before applying the coating should be a maximum of 3%. The coating is suitable for all mineral substrates such as concrete surfaces, cement screed, anhydrite substrates, etc., as well as for systems with underfloor heating.