Simply specify rockwool next time you insulate.  It’s an upgrade worth every penny you pay for it and more.  It’s a natural mineral product that doesn’t rot or burn and if that’s not enough to like, it’s a very effective sound insulator as well.  Put it everywhere – walls, between floors, ceilings.   Comes in compressed batts, but they’re heavier than fiberglass and more like loaves that you slice.  Call in the pros of course.  I’m not sure anyone ever saved any money insulating on their own – it hard to make it pencil out.

Rockwool is very commonly used to isolate sound in condos, apartments, hotels and other commercial buildings, but it definitely deserves a bigger role in everyday residential work.  Same R value as fiberglass per inch, but far superior when it comes to creating silence.   Who couldn’t use a little more of that?