Looking to soundproof the wetroom/shower as much as possible. My daughter's taste in music....hurts everyone's ears so my son whose bedroom is on the other side of the stud wall won't want to hear her 'sing' in the shower! It's a 95mm stud wall with Schluter kerdiboard and 9mm tiles. My plan was to either fill the stud wall with PIR (95mm) or use up my acoustic loft roll type stuff (Superglass roll) that I still have lying around. Alternatively, I was going to go fit the acoustic stuff in the st