no the stuff I'm talking about is 1/2" thick and is only like $10 for a 4x8 sheet. It is really dense fiberglass but then again I don't really know what undense fiberglass is, or for that matter if it is indeed fiberglass. I can not find any info on it anywere. I was holding someone with more knowledge than me could help. If any one goes to hd any time soon and get a chance look for it, it's a black 4x8 sheet and has green print that says quiet barrier. Thank for trying though!