A “floating floor” refers to any type of flooring that is not nailed and/or glued down, hence “floating”. An underpad to a floating floor is similar in principle to wax paper to a ground-mounted floor (a floor that is glued and/or nailed). The benefits of an installed underpad are not to be understated. Underpad acts as a
moisture, temperature, and friction barrier between floor and subfloor; as well as offering a noticeable noise reduction to floors below. Overall, underlayment promotes the longevity of a floating floor, in addition to improving the quality of life of the floor (i.e. noise reduction, softer to the step...etc). The cost of underpad belies its benefits, most underpads starting at $0.20/SqFt-$0.25/SqFt, there should never exist a floating floor without its foundation.