Examine the room you want to buy carpet padding for. If it is a high-traffic room, you will need to purchase a rubber carpet underlay with closed-cell foam underneath the soundproofing barrier layer, because the variety with open-cell foam will not last under heavy use.
Measure the size of the carpet under which you want to place the rubber carpet padding.
Take your measurements and information about the room you are soundproofing to a flooring store to buy a pad and have it cut to the appropriate size. For high-traffic areas, choose a quarter-inch-thick pad; purchase a half-inch-thick pad for low traffic areas.
Take your rubber carpet pad home and unroll it onto the clean, dry floor you wish to soundproof. Lay your [rug](https://society6com/rugs?utm_source=SFGHG&utm_medium=referral&utm_campaign=8775) or carpet on top of the padding, being sure that the surface of the carpet covers the rubber padding completely.