Wall design using a propietary polymer layer . .

Thanks again Andre . . I will sit down this evening and read the white paper you suggested. I am by trade an electical engineer, but this world of sound isolation is fairly new and most interesting. Thank God for people like you to go the extra mile and are willing to lend a hand. My son is outside right now putting up a temporary wall for the winter behind the garage doors as we have decided to close things up and focus on the existing building and make the addition in the spring. I was thinking of putting liquid nails around the perimeter of the area where I will be adding the drywall to the interior and squeezing it into the crack between the studs and the fiberboard and then adding the second exterior layer with my viscoelastic material applied on top of that. Then I will use the new walls I put up with RC and 2 or three layers of drywall along with the visco material. Here is what the building looks like and the foregone addition until spring. thanks again . . I hope I can someday help out as well.