Cork is built from roughly 40 million closed cells per cubic centimetre. Each cell is a sealed pocket of air bounded by suberin walls. When sound waves enter the material, that geometry forces energy to dissipate as heat rather than transmit through the substrate.
The result is broadband attenuation. Where many synthetic acoustic foams perform well above 1 kHz but lose effectiveness in the lower mid-range, cork granulates and agglomerates remain effective from roughly 100 Hz upward, particularly when laid in densities between 180 and 250 kg/m³.
For floating floor systems, a 3 to 6 mm cork underlay typically delivers 18 to 22 dB of impact noise reduction, depending on the granulometry chosen. For wall systems, denser blocks built from coarse granulates and a natural binder behave as a mass-spring-mass element without the formaldehyde and isocyanate chemistry of synthetic alternatives.
Specification tip: ask your cork supplier for the granulometry curve, density and binder type used. Performance is not a property of cork in the abstract; it is a property of a specific formulation engineered for a specific frequency target.
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