I am thinking about using a 6 mil poly and a thicker sound/water barrier to make walking on the floors a bit softer. I plan to tape (or use silicon) as a means to seal moisture.

My question is, is it a good strategy to completely seal the floor like this? Judging by my crawlspace (which is sealed with 6mil poly), droplets gather underneath. Wouldn't the same happen for my insulation under the hardwood? Would it damage the concrete?