Is Foam Board Good For Soundproofing? No, Here’s Why…

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As a nightclub owner, have you ever wondered if cheap foam boards could potentially dampen the booming bass and raucous crowds packing the dancefloor every weekend?

While foam board may seem like an affordable quick soundproofing fix, the truth is that foam board cannot meaningfully reduce noise in crowded, pulsating nightclubs.

Let’s dive into why foam board fails as a DIY soundproofing solution and explore better materials for containing the thumping music and crowds.

What is Foam Board?

A detailed cross-section reveals the inner workings of foam board—a composite of solid polystyrene foam embraced by protective facings. The versatile material, depicted in its recognizable white hue, showcases its structural integrity and insulation capabilities. Images further illustrate foam board's applications in arts, crafts, architectural models, and insulation projects, emphasizing its adaptability across diverse creative and construction endeavors

Foam board refers to a versatile, lightweight insulating building material that consists of a solid polystyrene foam core that is laminated between two outer thin facings of paper or cardboard.

This sandwiched composition gives foam board both rigidity and protection for construction applications.

Foam board panels are a durable, weather-resistant product typically sold in large standardized sheet sizes such as 2 feet by 2 feet squares or 4 feet by 8 feet rectangles to align with common dimensional lumber sizes.

Foam board sheets are also available in a range of thicknesses to meet different insulation needs, with 1⁄4 inch, 1⁄2 inch, and 1 inch being some of the most widely used dimensions.

The solid polystyrene inner foam layer of foam board provides structural rigidity and insulation value.

Polystyrene is a petroleum-based plastic material structured around hydrocarbon polymers that help trap air pockets and provide an effective thermal barrier to slow heat transfer.

The foaming process allows the very small polystyrene foam beads to expand into lightweight closed-cell foam through the release of pentane gas.

This airtight cellular composition prevents airflow while limiting heat conduction. The middle foam layer gives foam board products their recognizable white color and smooth surface texture.

Meanwhile, the thin outer facings of paper or cardboard bonded to each side protect the inner polystyrene foam insulation and also allow pins, nails, adhesives and art materials to adhere firmly to the surface.

Common facing materials include cardstock paper facings with a clay coating for water resistance or a foil facer for radiant heat reflection.

These laminated outer layers serve both aesthetic and functional purposes.

Overall, the combination of dense foam insulation sandwiched between protective bonded facings provides foam board with favorable properties of strength, rigidity, and versatility for building projects.

Foam board has become an exceptionally popular choice for many arts, crafts, hobby, and school activities due to its light weight, ease of handling, and capability to be precisely cut, shaped, bent, curved, and joined in numerous creative ways.

The white foam surface takes paint, glue, and other decorative elements well.

Foam board’s simultaneous rigidity and lightness also make it valued for architectural and engineering scale models, theatrical set and prop construction, and similar applications.

This foam board product is even sometimes utilized in full-size construction and remodeling projects as an insulation or decorative material.

It can provide supplemental thermal insulation when positioned inside walls, unvented attics, crawl spaces, basement rim joists, concrete formwork, and other building structural elements.

Strategically placed foam board insulation reduces conductive, convective, and radiant heat transfer through a building’s envelope.

Additionally, foam board sheets serve as a suitable smooth backing material for mounting photographs, posters, artwork, signs, and flat panel displays since fasteners and adhesives adhere cleanly to the outer facings.

Is Foam Board Good for Soundproofing?

In the visual representation, the inadequacy of foam board for soundproofing is evident as sound waves effortlessly pass through its porous composition. The lightweight nature of foam board is highlighted, showcasing its inability to impede impactful noises. A side-by-side comparison emphasizes the need for more effective alternatives that provide the necessary density, sealing, and decoupling attributes for substantial noise reduction. Explore the following sections to delve deeper into the limitations of foam board and discover recommended alternatives for superior soundproofing

No, Foam board is not good for soundproofing

The porous, hole-filled composition of expanded polystyrene foam lacks the density and mass necessary for effectively blocking lower frequencies and significantly impeding impact noises.

The foam is inherently designed to trap air rather than reflect sound waves.

Foam board sheets are also thin and lightweight per square foot, making them unable to meaningfully hamper the transmission of thunderous noises like music, machinery, heavy footsteps, or loud voices through walls, floors, and ceilings. Any partial noise reduction occurs only at the surface level.

Furthermore, the seams between abutted foam board panels create flanking paths for noise leakage without extensive caulking.

While foam board insulation may seem like an easier, more accessible DIY soundproofing solution on first glance.
It fundamentally lacks the proper composition, density, sealing, and decoupling attributes required for sufficiently blocking.

Ambient noises and achieving meaningful noise reduction throughout a room or building structure.

Individuals wanting to take on substantive soundproofing projects should avoid relying solely on foam board panels and instead.

Utilize products specifically engineered for superior acoustic insulation and noise blocking capability.

The next sections will explore in greater detail the pros, cons, limitations, and recommended alternatives when it comes to utilizing foam board products for soundproofing needs.

Cons of Using Foam Board for Soundproofing

A visual exploration of the limitations of foam board for soundproofing. In the depicted scenarios, sound waves effortlessly permeate the porous and lightweight foam board panels, highlighting its deficiencies in mass, density, and composition. The contrast with a more effective acoustic solution underscores the importance of materials specifically engineered for professional-grade soundproofing, emphasizing the cons of relying on standard foam board for comprehensive noise reduction

While foam board does exhibit a handful of characteristics that could aid slightly with damping or
obstructing noise, it ultimately has significant deficiencies that preclude it from being an effective core soundproofing material:

Lacks Sufficient Mass and Density

The chief reason foam board fails as an adequate noise blocker is its lack of mass and density.

Optimal acoustic insulation requires very dense, heavy barrier materials and absorbers in order to isolate, dampen.

Decouple noise transmission through vibration damping and maximized surface area.

With foam board weighing approximately 1 to 2 pounds per square foot based on its thickness, it is far too lightweight and wispy to provide meaningful soundproofing capabilities.

The polystyrene foam is purposely engineered for rigidity and low weight, not noise blocking through mass. Sounds easily pass through the matrix of tiny air bubbles unimpeded.

Too Porous and Perforated

Related to its lack of sound-reflecting density is the fact that foam board is purposely designed with a porous, hole-filled composition that allows noise to transmit through rather than containing it.

The foam insulation relies on pockets of trapped air for thermal insulation. But these microscopic air voids dispersed throughout the foam leave it acoustically transparent rather than sound reflective.

There are too many paths for noise waves to pierce through rather than being reflected and absorbed by dense barriers facing an air space.

Allows Flanking Noise Transmission

Another downside of foam boards is that when installed on walls and ceilings in panels, there remain seams between each board that are open for flanking noise transmission.

Even when panels are carefully joined flush, the tooth-gaps lead to acoustic leakage that bypasses the boards altogether.

This grants noise easy access around the perimeter of the foam boards.

Extensive acoustic caulking is required with any foam board application to mitigate this fundamental issue, and even then density and isolation are lacking.

Limited Low Frequency Sound Blocking

While foam board may dampen some high pitched sounds that directly hit its surface, it lacks the composition to effectively block lower frequency noises.

As the wavelength of sounds decreases, foam becomes increasingly acoustically transparent.

Bass frequencies, music, heavy footsteps, loud conversation, and other impactful sounds can penetrate through foam unimpeded.

Only materials with tightly sealed, dense, highly absorptive compositions can contain noises across the entire audible spectrum.

Not Designed for Acoustic Use

Finally, polystyrene foam board simply was not designed or engineered to serve as an acoustic insulating material in any capacity.

The sole purposes of foam boards are thermal insulation for improving building energy efficiency and providing a smooth backing surface for arts and crafts.

Home builders and sound engineers would never view standard foam board as a legitimate soundproofing product.

Materials specifically developed for noise blocking and room acoustic treatments are necessitated for professional-grade results.

Recommended Superior Soundproofing Materials

A visual guide to superior soundproofing materials designed for effective noise absorption and containment. From mineral wool and fiberglass insulation to soundproof drywall, Green Glue Noiseproofing Compound, mass loaded vinyl, and acoustic caulk, each material is displayed with clarity. This comprehensive visual guide underscores the variety of purpose-built options available for achieving professional-grade soundproofing, emphasizing the need for specialized materials over standard foam board

While foam board alone fails as an effective noise insulating material, there are a number of purpose-built soundproofing products designed to adequately absorb, block, and contain noise pollution in rooms.

Individuals exploring both DIY and expertly-installed solutions should consider the following superior materials:

Acoustic Insulation

Specialized acoustic insulation refers to materials explicitly designed to dampen and absorb noise transmission when installed within the cavities of building structures.

Common forms include fluffy fiber insulation or rigid insulation boards comprised of dense, sound reflecting materials.

  • Mineral Wool Insulation – Mineral wool refers to a fluffy fibrous insulation material spun from molten rock or recycled industrial slag into a cotton candy-like substance optimal for sound absorption. Brand names include Rockwool and Roxul stone wool.
  • Fiberglass Insulation – Sound dampening insulation can also be fabricated from spun molten glass fibers bound in place with thermoset resins. Popular versions include Owens Corning 703 Rigid Fiberglass Boards.
  • Cellulose Insulation – Loose cellulose fibers made from recycled materials provide both outstanding thermal insulation and acoustic absorption when blown into cavities.
  • Spray Foam Insulation – Foams like closed-cell polyurethane effectively seal air gaps while limiting noise transfer when professionally spray-installed into existing hollow walls and ceilings.

Soundproof Drywall

Specialized lightweight yet highly dampening drywall products containing compounds like vinyl or latex improve sound isolation when replacing standard drywall. Brands like QuietRock work by limiting surface vibration transfer. Staggered double drywall layers are ideal.

Green Glue Noiseproofing Compound

Green glue is a patented viscoelastic polymer compound applied between drywall or paneling layers to convert acoustic energy into heat energy through its unique ability to dampen vibration movement rather than transmitting it through the adhesive bond it creates.

It profoundly limits sound transmission and resonance.

Mass Loaded Vinyl

Mass loaded vinyl is an elegant sound barrier solution popular in theaters and studios which contains barium salts or other mineral fillers to provide weighted vinyl sheeting that blocks noise transfer through wall, floor, and ceiling structures.

Mass loaded vinyl is installed onto existing surfaces or under finish materials using adhesive and can be layered in combinations with other insulators.

Acoustic Caulk and Sealants

Finally, specialized caulking and sealing compounds are essential for completely sealing voids, cracks, outlets, windows, vents, trim, ducts and all other penetration points that compromise the integrity of the acoustic envelope and lead to flanking noise transmission.

Quality brands include Green Glue Noiseproofing Sealant and OSI SC-175 Acoustic Sound Sealant. Careful application prevents sound leaks.

Conclusion

In conclusion, while standard foam board insulation sheets may initially seem like an easier, more accessible option for DIY residential soundproofing due to a few helpful properties, alone foam boards are ineffective for meaningfully reducing noise transmission.

The porous foam composition lacks sufficient density, mass, air sealing and dedicated acoustic dampening capabilities.

Individuals wanting to successfully diminish sound transfer through walls, floors, ceilings and doors in their homes, offices, studios or theaters are best served by utilizing purpose-built acoustic insulation, noise barrier, and isolation products as recommended.

With diligent product selection and thorough installation, significant noise reduction is possible. But for most applications, foam board should be avoided as a core soundproofing material, relegated instead to its intended use cases as a thermal insulator or hobbyist’s creative medium.

Dominic

Dominic is the chief editor of the Burton Acoustix blog which writes about acoustics and soundproofing to help readers with their queries and questions they might have with regard to improving any sound or noise issues that they faced in their life.