If SoundStep LV has a moisture barrier, what is the perm rating? Table of Contents Join Our Newsletter You are about to install your new flooring. As you lay the first plank you realize that Name(Required) First Email(Required) HiddenHubspot Form Source CAPTCHA Share Categories Carpet Pad Floor Underlayment Radiant Floor Heating Surface Protection Uncategorized Under Deck Ceiling Post navigation Previous: Is SoundStep LV waterproof? I am looking for something thin and easy to put over plywood.Next: I’m going to be using an engineered hardwood over a plywood subfloor on the concrete slab. Can I install QuietWalk over plywood subfloor under hardwood floor?