Can I use DMX for airflow and the Smartcore 3mil underlayment on top?

Robert, Thank you for reaching out in regards to SMARTCORE Ultra Blue Ridge Pine lvt Flooring. No that product can not be used it would create to much deflection. All subfloors must be clean, flat, dry, and structurally sound. The correct preparation of the subfloor is a major part of a successful installation. Subfloor must be flat: 3/16" in 10' or 1/8" in 6'. A second underlayment is allowed under any currently sold Shaw/Coretec Product with 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 installation of underlayment and flooring. If you need additional assistance, feel free to contact a member of our SMARTCORE concierge team by emailing asksmartcore@smartcorefloors.com or call 1-800-355-7429, option 5, then option 1. We are available M-F from 8:00 AM - 6:00 PM, ET.- LG, SMARTCORE Team