Any ideas on what to use as a sound barier in bathroom walls. I am thinking fiber glass would not be the best choice due to moisture and it is in the basement. I am using the foam board on my exterior walls so would this work for the interior walls around our bathroom as well? If foam board is the best in this application would I hang drywall on one side of the wall then attach the foam board with adhesive to the drywall before hanging the other side of the wall. Only purpose would be to keep it from shifting even though it would be cut to fit tightly. Thanks!