Ok...here's the deal. I know pretty much every laminate calls for a vapor barrier when installing over concrete.

I want to install laminate over existing extremely low commercial grade carpet which is currently in place over slab concrete well above grade. I'm not worried about going over the carpet as I have done this before with subfloor underneath....but more about the "vapor barrier" aspect.

I guess my question is this:

Does concrete somehow "wick" moisture from the earth below? Again, it is not at all below grade (commercial construction, ground level). the concrete is 15+ years old.

I'm worried that if i do put a barrier over the carpet...I'll end up with mold growth, strange odors, etc.

BTW, the floors I am considering are a 12mm Quickstyle (water activated glue in groove)...or an 8mm Unifloor type.

thanks