Unlike open or even close-celled synthetic foam materials, cork consists of an interlocking structure of 14-sided polygons called tetracadecahedrons. These totally sealed gas filled cells have a very tough outer surface that is almost impossible to break. Because of this unique natural attribute, cork has a compression/recovery rating of close to 100%. Unlike many foam and fiber based products, it will not collapse over time with traffic. The binders used to adhere the granules of AcoustiCORK products together are designed to create a permanent structural bond between the particles.