Covering old glue and leveling
We have removed 2 layers of old vinyl tile (no astestos! - we had it all tested before we began) and plan to install vinyl tile. The floor has old, black glue that is impossible to remove. Also, the floor is not completely level. Some areas are off by 1/4 to 1/2 inch. Congoleum recommended that we level the floor with a portland cement with latex additive and then cover the black glue with rosen paper, then install a 1/4 inch plywood underlayment. The problem is in what to do with the floor to level it. We can't use self leveling compound because after speaking with the LevelQuik company they told us that we would have to first put in a metal lath (mandatory) and they don't recommend their product for use with vinyl flooring. We can't use gypsum based because it would crumble when we go to install the plywood underlayment over it with screws or staples or nails. Henry -another company - has recommended that we put the rosen paper down first, then the 1/4 inch plywood underlayment and then level the floor with their Featherfinish portland cement with latex additive. Will this work? Will we still be able to determine where the low spots are that need to be leveled once the 1/4 inch plywood underlayment is down? Any suggestions are appreciated!