Substrate
Concrete, cement screed, sound tiling, cement and cement-lime plaster.
Surface preparation
First of all, clean the structural slab of loose material and non-adhesive layers. In case of repair work, the remains of old waterproofing layers and screed must be removed and the condition of reinforcement should be surveyed. That should be done by a duly authorised person. Then, appropriate surface slope can be profiled, unless already provided to the slab. For slab repair, i.e. smoothening irregularities and working out the desired slope, use the ALPOL AZ 130 quick setting mortar, or ALPOL AZ 135 levelling mortar. Properly treated surface of the slab should be dry, clean, free from dust and contamination.