Ceresit CR 64 may be applied on rough and load carrying surfaces e.g. renovation plasters, concrete, traditional plasters free from grease, bitumen, dust and other substances that decrease adhesion. Any dirt and weak layers should be completely removed. It also refers to all anti-adhesion substances and painting coats. The surfaces that are of slight absorptions or inhomogeneous dampness should be moistened with water. Before the application of filler the surface should be damp, but not wet. Dry and extremely absorbable surfaces should be primed with Ceresit CT 17 and dried within approximately 4 hours.