Often, we want to make a new floor on the old plank floor. This requires the implementation of an appropriate undercoat to ensure the correct laying of the new floor. One solution is to use a special plasterboard system with a layer of polystyrene or mineral wool on the bottom. Plates without additional thick insulation 12,5 mm is put in two layers, perpendicular to one another, on a protective layer of foil or wrapping paper. We glue them with glue and screw them together.