What is Rockwool?Roxul Stone Wool is an insulation product that comes in the form of batts. It's composed of mineral fibers and it's considered to be green, fire-retardant, and very good for sound control. Like cellulose fiber, it insulates airborne noise better than fiberglass.
In the USA, you can buy Roxul at Lowes and some Home Depot locations. In Canada, you can buy Roxul in Saskatchewan at Rona Corporation in Prince Albert or at Econo Lumber.
Roxul comes in packages of pre-cut sizes that fit the dimensions of your wall cavities (for example, use these 15 1/4-inch batts for wall studs that are 16 inches apart). Be sure to select the right size for the job – not just the width, but the depth as well (wall versus ceiling or attic).
Rockwool is great in wallsThis video from Roxul demonstrates how to install Roxul in a wall. As you can see, it cuts easily with a bread knife and can be custom fit around electrical lines, plumbing, and wall outlets. It holds a snug fit between the wall studs.
You should wear gloves and long sleeves when you work with the product, because it's very itchy.