I need to install laminate over old vinyl tile flooring in a 1950's house (similar situation to earlier posting by mimiandalex in 2010) As tile likely has asbestos, need to go over it. In the responses to aforementioned earlier post, product recommended was self-leveling material by Ardex. This project is in kitchen (which has cabinets, dishwasher, etc, sitting on floor, as well as a stairwell going down to the basement) and in an adjoining hallway, which leads to 3 carpeted bedrooms, a carpeted living room, and a tiled bathroom (which sits lower than the hallway.) Can the self- leveling product be applied only to the most sagging areas, to avoid the material going where it is not wanted/needed? Or what else would be advised?