Looking to isolate sound? You found the right guys.

IIC ratings only cover mid-to-high frequencies (125 Hz to 4,000 Hz), leaving low-frequency footfall thumps untreated when floors deflect under load. To address this, IsoStore recommends three strategies: (1) increase stiffness with stepped blocking, (2) add decoupling (e.g. resilient clips like GenieClip), and (3) use damping (such as Green Glue) between layers. Combined, these methods control structural vibration and improve overall acoustic performance.

Damping refers to how quickly a material dissipates vibrational energy: higher damping means more energy converted to heat and less noise transfer. In soundproofing, constrained layer damping (e.g. Green Glue between drywall) and extensional damping (e.g. pipe wraps) are two common methods. Damping also helps control resonance and prevents vibration from propagating through structures over distance, complementing STC test results.

The triple leaf effect occurs when two air cavities exist instead of one, common in retrofits where new walls or resilient clips are added over existing drywall. Although it’s logical to assume more layers improve isolation, tests show triple and quadruple leaf assemblies degrade performance and often underperform compared to properly decoupled double-leaf systems. Insulating the added cavity (e.g. with R-8 fiberglass) can partially recover lost isolation, but the best approach is avoiding triple leaf construction.