Do I need an underlay?

Linda - Thanks for reaching out with your question. A second underlayment is allowed under any currently sold Shaw/Coretec Product with an attached underlayment in a residential application. IIC (ASTM E492-09) and STC (ASTM E90-09) lab testing on certain Shaw/ Coretec products tested with and without a second layer of underlayment, to date, does not indicate that a second underlayment will provide additional acoustic benefit. When used the second underlayment must be a maximum of 3 mm thick and have a minimum density of 190 kg/m3 or 11.7 lb/ft3. The additional underlayment when used must be fully adhered to the subfloor with the appropriate adhesive. The subfloor must meet all requirements of being clean, flat, dry, and structurally sound prior to the installation of underlayment and flooring. If you have further inquiries, you may contact our Information/Technical Department at or 800-441-7429. - LG, SMARTCORE Team