Preparation of the substrate
CT 81 has very good adhesion to sound and carrying substrates, such as wall, plaster and cement substrates free from grease, bitumen, dust and other substances decreasing adhesion. The adhesion to the existing plasters and paint coatings should be checked before starting the application. ”Hollow” plasters should be removed. Any losses and uneven surfaces of the substrate should be filled or covered with cement plaster. Any surface contaminant and other adhesion impairing substances, steam-tight paint coatings and the coats with low adhesion to the substrate should be completely removed, e.g. by means of washing devices operating under pressure.
Substrates with high water absorption, e.g. walls made of aerated concrete blocks or silicate blocks should be primed with CT 17 and left for drying for at least 4 hours. Before fixing EPS-boards the adhesion of the mortar should be checked by fix polystyrene boards (10x10 cm) to the prepared substrate and tear them of after 2-3 days.