It is important not to forget to assess the state of the surface of the base. It should be absolutely solid, even and dry. All traces of paint, plaster, mortar crumbs must be removed. Possible cracks, excavations and protrusions are leveled using compounds on a cement basis. It is also necessary to check the moisture content of the floor. To do this is quite simple — it is enough to lay on the base of the floor polyethylene in size of the order of 1 x 1 m. If, after 3-4 hours, condensate did not appear on its lower side, then you can start laying the coating. Otherwise, special drying compounds should be used.