Does MSI LVP need underlayment?

MSI Everlife LVP does not need additional underlayment over plywood subfloor, as Everlife LVP has attached pad that provides cushion and sound absorption, but does require 6 mil vapor barrier over concrete subfloor if moisture present per installation instructions. MSI Everlife luxury vinyl plank, sold by MS International at $2 to $4 per square foot materials, features rigid core construction that is 100 percent waterproof, attached pad that is typically foam or cork that provides comfort, warmth, and sound absorption, and click-lock floating installation that floats over subfloor, similar to LifeProof and COREtec. Over plywood or OSB subfloor that is dry and flat within 3/16 inch over 10 feet, MSI Everlife LVP does not require additional foam underlayment, as attached pad is sufficient and adding extra underlayment may void warranty by making floor too soft and unstable, causing click-lock to break. Over concrete subfloor, MSI installation instructions require 6 mil polyethylene vapor barrier if concrete moisture exceeds 5 pounds per 1000 sq ft or 75 percent relative humidity, to prevent moisture affecting subfloor and causing mold, though Everlife LVP itself is waterproof. Always follow MSI installation instructions for your specific product. So MSI LVP does not need underlayment over plywood, but requires vapor barrier over concrete if moisture present, and do not add extra foam underlayment.