Amerrock is a spray-on rockwool insulation made from one of the oldest and most trusted fibers in the United States. Amerrock is manufactured with a dry adhesive built into the product which requires the addition of water to activate the cohesive and adhesive strength for closed cavity applications. With a density of 4 lbs. per cubic foot, Amerrock has greater mass than most other insulation fibers (mineral, glass or cellulose) thus adding to the overall partition mass and decreasing the air infiltration rate while increasing sound control. Because we use a total system (fiber, adhesive, approved spray equipment and qualified applicators), Amerrock has an exclusive "Lifetime Warranty".