Originally Posted by BIGmouthinDC
Doesn't it give you cause for concern when your contractor is either stupid or a liar.
So many, and perhaps most, unfortunately are. A few weeks ago, I had a drywaller tell me the Certainteed ProRoc Easi Lite he was hanging in my bathroom wall shared with a bedroom to be 'the standard weight stuff' to which I said it's not, and that I wanted the regular, heavier weight drywall, as the objective was to reduce sound transfer from the bathroom to the bedroom with the double drywall and green glue assembly I asked him to install. He again stated that this was the standard, and that there was lighter stuff that he doesn't use. I let him know that I've bought, hauled, and hung enough sheetrock to know the difference and that it was clearly labeled as 'Easi Lite' on the sheetrock. He simply said, 'it's still heavy' which pretty much summed up why it was going up in my bathroom. Annoyed, but wanting to have my bathroom done sooner rather than later, and as him stopping work, going to the supplier, and charging me all the way for his additional time and additional materials, I let him carry on. Now I've got a 30% lighter than desired DD&GG assembly in there.
Roxul SS and CB are similar but not the same. They're okay in the other's intended purposes however, and further, insulation isn't terribly important. You can use any readily available insulation really with very similar results. Other factors to SP are far more important. Check out soundproofingcompany.com to take the course soundproofing 101.