This may go down in a commercial establishment @ 4000 ft one room. I bid to remove adhesive and grind slab to accept a concrete stain but they may not accept the bid and just put this floating vinyl over probably 6 mil sheet plastic. Not sure if Floor is flat, just need opinions if they don’t use vapor barrier, or issues with adhesive residue. They may scrape as well, would there be sound issues?(attached foam) The adhesive is semi brittle. Staining issues if the barrier isn’t used. If they don’t provide expansion what will be the issues? What does it end up looking like, cupping? Want to know down the road if they made the wrong decision and will have to spend mo money.