Common misconceptions about Cork

Cork is a completely natural raw material, with unique properties which give it an unrivalled character Why Cork

Cork will absorb water like a “sponge” if it gets wet.

Incorrect: Think of the most common use for cork, wine stoppers. Cork has been used for wine stoppers for hundreds of year primarily because it does not absorb water or liquids. Cork has also been used for years in buoys, lifejackets and other floatation devices, again because it does not absorb water and can remain buoyant for years.  A cubic inch of solid cork immersed in water for 48 hours will gain less than 3% in weight due to water absorption. A cubic inch of solid wood or unglazed clay-bodied ceramic tile would gain many more times this percentage of weight in water if immersed for 48 hours.

Composition Cork material will fall apart if it gets wet after it has been installed.

Incorrect: That may have been possible over 20 years ago when animal protein binders were used, but not anymore. Since the early 1980’s non-water-soluble polyurethane binders have been used to adhere the granules together to make Amorim composition cork products. These polyurethane binders also produce no post installation off gassing and do not leech into ground water supplies. AcoustiCORK products can be totally immersed in water for 30 days or more and show no signs of structural deterioration. The natural wax like content of cork, which is a substance called suberin,  protects it from rotting or decomposition, even if it is submerged in water for long periods of time.  

Cork will “swell” with exposure to moisture and cause finish floor coverings to fail.

Incorrect: Because cork absorbs so little water, it is very dimensionally stable. When exposed to 100% Relative Humidity conditions for 30 days the dimensional change in the grade of materials used to manufacture AcoustiCORK products would be less than 3%. In a 6mm (0.236”) thick piece of material this would represent an increase in thickness of less than 1/120 of an inch. 

Cork underlayment will compress and crumble under heavy loads and traffic.

Incorrect: 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 membrane 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.  

Cork will support the growth of mold and mildew if used in a moist environment

Incorrect: Going back to the traditional use of Cork in wine stoppers, solid Cork is used for sealing fine vintage wines precisely because it does not readily support the growth of mold and other biological agents, which can cause spoiling of the wine. About 45% of the mass of cork is a waxy compound known as suberin. Suberin is where the species name of the tree is derived from (Quercus Suber L.) and it makes cork naturally mold and mildew resistance, as well as resistant to termites and fire. Also, the granules of Cork used to make AcoustiCORK products are coated with a polyurethane binder, which enhances their natural microbial resistance. 

“Cork is Cork” and all Cork Underlayment products are the same.

Incorrect: Properties such as density, particle size and consistency of particle size are very important and vary widely from one manufacturer to another. Density affects the structural stability of the product and the sound attenuation quality. A product that lacks density will be too delicate to use as   an underlayment and a product that is too dense will have poor sound attenuation characteristics. A product that has too large of particle size or a wide range of particle sizes in the mix will lack the structural integrity to be effectively used as an underlayment. The Mediterranean Cork Oak is a much different  species of tree, with more resilient properties and Suberin content, than the Chinese species of cork tree. AcoustiCORK products are made with 100% Mediterranean Cork granules and high quality, non-toxic binders. The same cannot be said for generic imitations.