I'm in the very long process of finishing our basement. My next step is to put in laminate flooring in what will become the family room. The underlay/laminate will be going on top of concrete floor. My question is about the underlay. I know some type of vapor barrier is needed. The manufacturer says that 6 mil vapor barrier is required if your concrete sub floor gives off a certain amount of moisture. I haven't measured this, and it doesn't seem like an easy thing to do. So my question is can I put down the 6 mil vapor barrier AND put down the underlay I want to use, which does have a vapor barrier as well which is very thin, but also has a layer for air which is supposed to keep the floor warmer? I've tried googling but haven't found any info on putting down 2 layers of vapor barrier to see if this could somehow negatively effect the floor. I've never noticed any moisture issue with the floor in the basement. The laminate is 14 mil, and seems to be of good quality if that helps. Any input is appreciated.