Second Skin Overkill Pro Closed Cell Foam – High Density Polyethylene Foam Decoupler (1 Barrier Sheet – 9 Sq. Ft.) – Made in USA is a 3/8 inch thick closed cell polyethylene foam sheet designed primarily as a decoupler within vehicle sound control systems. Engineered to work alongside sound deadening and barrier products, this material is intended to reduce rattling, vibration noise, and certain low-frequency sound waves inside automotive interiors.
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Material Composition and Construction
This solution is manufactured from closed cell polyethylene foam and measures 54 inches by 24 inches per sheet, providing 9 square feet of coverage. With a thickness of 0.38 inches, the material is structured to create a cushion between hard surfaces such as plastic panels, metal components, speakers, and mass loaded vinyl barriers. The closed cell structure is described as highly water resistant and heat resistant up to 165 degrees Fahrenheit. It carries an R-value per inch of 4.33, positioning it as a high-density insulation layer suitable for interior automotive environments.
The foam has been tested for safety and is described as not off-gassing chemicals, making it suitable for use inside vehicle cabins. Installation guidance indicates it should be applied within the interior cabin and not positioned next to a direct heat source.
Decoupling and Noise Control Function
As a decoupler, this material is not intended to block or absorb large amounts of sound on its own. Instead, it is designed to separate rigid surfaces to prevent vibration transfer and rattling. When installed between plastic panels, subwoofers, metal surfaces, or under a mass loaded vinyl barrier, it creates a cushioning layer that reduces mechanical vibration noise.
Within automotive audio systems, it is also described as reducing distortions caused by sound waves reflecting within door panels and cabin cavities. By acting as a closed cell foam “carpet,” it helps reduce the empty room effect inside door panels, supporting improved speaker acoustics. In addition to vibration control, the material is noted to absorb some low-frequency sound waves, targeting road noise, engine noise, and exhaust noise.
For readers evaluating specifications and compatibility details, the full product listing can be reviewed here: closed cell polyethylene foam decoupler sheet.
Installation and Application Context
This sheet is recommended for use as a decoupling layer in conjunction with barrier products, particularly under mass loaded vinyl on vehicle floors, firewalls, and trunks. It may also be installed behind plastic panels to reduce rattling and vibration. Suggested application methods include high temperature spray adhesive or strong double-sided tape when a permanent bond is desired.
Because the material is designed to cushion surfaces rather than serve as a primary sound barrier, it is most effective when integrated into a multi-layer automotive sound treatment approach. The manufacturer specifies that polyethylene foam should not be used adjacent to direct heat sources, reinforcing its intended placement within protected cabin areas.
Additional product dimensions, thickness, and material specifications are available on the official listing for this 3/8 inch closed cell foam sheet.
Performance Characteristics in Practical Use
Across user feedback, commonly repeated characteristics include effective reduction of rattles within doors, trunks, and roof panels, as well as support for improved speaker clarity when installed behind interior panels. The material is frequently described as easy to cut and shape for custom fitment. It has also been used as an overlay above existing sound damping pads.
These repeated themes align with the product’s stated function as a decoupling layer rather than a standalone mass barrier. By isolating panels and cushioning gaps, the foam targets vibration-induced noise and secondary acoustic distortions inside vehicles.
Pros
Pros
- 3/8 inch thick closed cell polyethylene foam construction
- 9 square feet of coverage per sheet (54 inches by 24 inches)
- Highly water resistant
- Heat resistant up to 165°F
- R-value per inch of 4.33
- Designed to reduce rattles and vibrations by decoupling hard surfaces
- Absorbs some low-frequency sound waves
- Made in the USA
Cons
Cons
- Not intended to block or absorb large amounts of sound on its own
- Should not be installed next to direct heat sources
For those designing or upgrading an automotive sound treatment system, reviewing the detailed specifications of this high density polyethylene foam decoupler can help determine how it fits within a layered noise control strategy.