Looking to install bruce engineered hardwood flooring over a basement floor - which is concrete. The bruce install instructions for glue down mention installation of a slip-sheet to be safe for moisture over the concrete. What can be used as this slip sheet? Their instructions say
"inexpensive sheet vinyl or slip-sheet (PVC)".

If you are going to glue the floor down I would use the sheet vinyl. PVC sheeting is a roofing product and should come in different thicknesses measured in mills does the instructions call for a specific mill size, I have never used the product on a floor and don’t know if you can glue to it or not. PVC comes in very thick measurements for plastic so it could be the case. Usually manufacturers calls for polyethylene paper (not PVC) at 6 mill or higher if you are going to float the floor. Are you sure it was PVC.

This is directly from the instructions of the bruce engineered flooring - glue down or stapledown-

Moisture Barrier System: If moisture is present, inexpensive sheet vinyl or “slip-sheet”(PVC) may be installed. Use a premium grade, alkaline resistant adhesive and a full spread application system to properly bond the vinyl to the subfloor. Follow the sheet vinyl manufacturer instructions for installation procedures. A patch test may be required as an adhesion test. Install several small areas (3’x 3’) and allow the vinyl to set for 72 hours. Remove the vinyl; if the backing remains attached to the concrete, the subfloor should be acceptable for sheet vinyl installation.

sheet I found has this:

Moisture Barrier System: If moisture is present or anticipated, inexpensive sheet vinyl or “slip-sheet” (felt-backed with vinyl
wear layer) may be installed.