We are remodeling our living room and fireplace and tearing out the old carpeting and fireplace hearth. We will be installing engineered wood flooring throughout the living area and terra cotta tiles for the hearth. I removed a section of the carpet to get an idea what type of floor prep I have a head of me... and found this. I am working on an above grade concrete slab, and found this black/brown cardboard like material between the carpet padding and the concrete slab. It seems like it is going to be very tedious to remove all of this... so my questions are: 1. What is this material? 2. Can I install engineered wood flooring and terra cotta tiles over... or does it need removed. If it can stay, any preparation recommendations? 3. If it needs to be removed.. any tips for this process? Any advice or input is greatly appreciated. Thanks in advance for your help.