Just removed 12x12 vinyl tiles on concrete floor - want to put down Novalis vinyl floors - after the tiles cam up - there is a stckiy black adhesive on the floor - do i have to remove this or will it help adhere the new tiles?
The adhesive needs to be encapsulated by an engineered cementious underlayment compound specifically designed for the purpose. We call these skimcoats. If you don't isolate the adhesive residue, there is the danger that the tiles may not stick, because a chemical reaction between the two dissimilar adhesives may take place and destroy the bonding characteristics of each.
Ardex FeatherFinish fits into this category and Mapei makes PlaniPatch, and there are others. Read product descriptions to make sure any product you may want to use is the appropriate material.