The surfaces to be treated shall be dry, clean, strong, dense, and non-deformable. Any necessary preliminary leveling of the substrate shall be carried out at least 14 days before application of the compound.
The substrate surface shall be free of dust and cleaned from form-release agents, cement laitance, rust, oils, paint residues, putty, bitumen, and any other contaminants that may impair the adhesion of SPEKTRON Penetrating W20 to the substrate. Absorbent surfaces (cement screeds and plasters, concrete, etc.) shall be slightly pre-moistened with clean cold water using a spray bottle or a damp sponge before application of SPEKTRON Penetrating W20. This helps prevent excessively rapid drying of the waterproofing mortar. Any excess water remaining on the surface shall be removed with a sponge or compressed air.