Comment Exterior rockwool (Score 1) 388
We did 6" of exterior rockwool, triple pane windows with storms. GREATly reduces outside noise.
http://www.greenbuildingadviso...
It is not cost-effective immediately, however adding that much insulation on the house has about a 15-year payback on heating an cooling costs so it is cost-effective in the long run. Rockwool makes the house fireproof too.