Let’s be honest. Soundproofing is often an ugly affair, and it can get pretty expensive, too. If you have an at-home recording space tucked away in the basement or above the garage, aesthetics may not be top of mind. It’s not such a big deal to shove foam everywhere or drape ugly, heavy carpets.
But what if you want to improve the acoustics or soundproofing in a more public space, like your home theater space? Worse, what if your home theater space is in your living room?
People are drawn to cork for soundproofing for a number of reasons, aesthetics being one. The fact that cork acoustic treatments are made of eco-friendly sustainable materials doesn’t hurt, either.
Below, we’ll cover just about everything you might want to know about soundproofing with cork. We’ll cover the pros and cons and the acoustic properties of cork. Then we’ll round out this guide with explanations of how to use some of the most popular forms of cork for soundproofing.
Let’s start by discussing what makes cork good for soundproofing and acoustic treatment.
Is Cork Good for Soundproofing?
Cork is a quality soundproofing material, though its effectiveness varies depending on the application. There are other sound-absorption methods, including fiberglass and Rockwool, that will reduce more decibels than cork acoustic treatments will (in most applications). That said, cork-based acoustic treatments do a respectable job in many applications and an excellent job in some.
All soundproofing materials have their own acoustic profile, and cork is no exception. Cork tends to filter out the frequencies of the human voice particularly well, but it’s less effective against extremely low frequencies. Consider this profile (or the specific profile advertised on the product you’re considering) and whether it will do exactly what you’re needing. Or, you can use cork in combination with well-placed bass traps.
We’ll get into specifics about how the various applications work later on (see Types of Cork Soundproofing Products below). But first, we’ll look at some of the reasons people choose cork over other materials.
One serious consideration for soundproofing with cork is its cost. As a naturally occurring material, cork is relatively inexpensive. There are a number of higher-tech manufactured soundproofing materials out there. They are effective— in some cases, more so than cork. But generally, they cost way, way more than cork. If you’re looking for a budget-friendly soundproofing solution, cork is worth considering.
Cork is also extremely eco-friendly. Of course, most any wood product will be better for the environment than petroleum-based products (including all sorts of plastics, like fiberglass) because you can always plant a new tree. But cork has an advantage over other plant-based products that makes it even more sustainable.
Cork is made from the bark of the cork oak tree, and it’s harvested in a way that doesn’t kill the tree. In fact, cork trees produce enough bark to be harvested roughly every nine years, and the trees can live hundreds of years. If you’re looking for an eco-conscious method of soundproofing a space, cork is hands down one of the best choices out there.
Benefits of Using Cork for Soundproofing
We’ve already mentioned a few of the benefits of using cork for soundproofing above. We’ll reiterate those and add more to the list below.
- Renewable, Eco-friendly material: Because cork is made from bark that can be harvested without damaging or killing the tree, the environmental impact of using cork products is quite low. It’s more eco-friendly than just about any other soundproofing method.
- Wallet-Friendly: Cork products aren’t particularly costly, so it makes for an affordable way to absorb unwanted sound in your space.
- Easy to Use: Premade cork products like stick-on wall tiles are simple for DIY audiophiles to install themselves. Many products can be easily manipulated and installed without the need for specialized tools.
- Fire-Resistant: This one’s a surprise to many. You wouldn’t expect a product made from tree bark to have fire-retardant properties, but cork does. Cork forests are sometimes used as natural fire barriers. While some cork paneling isn’t going to stop a structure from burning, it won’t contribute to or start the burn.
- Aesthetically Attractive: No one will fault you if your recording studio looks a little funky. Recording studios are just kind of like that. They’re full of gear and acoustic treatments that aren’t built for conventional standards of beauty and home décor. But if you’re soundproofing a space that needs to look good, too, your significant other will likely object to your shoving massive ugly panels and foam wedges everywhere. Many cork products are actually quite attractive, making cork a great choice for spaces where aesthetics matter.
Drawbacks of Cork
Because cork is a natural wood product, it does have a few drawbacks.
- Water Damage: Cork that hasn’t been properly sealed is at risk for water damage. Cork floors can be beautiful, but they are susceptible to spills and leaks just as other wood floor types are. Sealing your cork floors every few years will help to keep them more water-resistant. Make sure you know the water-resistance of any premade cork soundproofing product before you install it, especially if you’re installing it in a basement studio or other space prone to moisture. Be aware of the care instructions of the product as well. Cork flooring may work similar to other wood flooring types, but other cork types and products may be even more porous (and thus more susceptible to water damage).
- Staining: Similarly, cork products are easily stainable. Bright substances, dyes in textiles, and ink from writing utensils could all do a number on any exposed cork product.
- Durability: Cork isn’t the most durable substance around. While that probably doesn’t matter for acoustic treatments on the walls, it’s a real drawback to cork flooring. If you’re considering cork flooring, you’ll need to be careful with it. (And don’t install it in a space with cats and dogs.)
- Puncture/Compression Damage: Lastly, as wood products go, cork is pretty soft. Sharp or heavy objects can easily damage cork, so be cautious when moving things around the studio. Keep your pencils and scissors away from any cork surface as best you can.
Acoustic Properties of Cork
As mentioned above, there are other products with strong sound reduction than cork, but cork soundproofing still provides a significant amount of reduction. Let’s look at some of the acoustic properties of this interesting acoustic material.
STC of Cork
One measure of a material’s acoustic properties is the sound transmission class or STC. While STC is going to vary depending on the type of cork soundproofing material, one vendor found that cork underlayment has an STC of 50 to 75 depending on thickness.
STC is, more or less, a measure of how many decibels a substance can attenuate. One study pegs 60 as the ideal STC for practically eliminating noise from a neighbor in a multifamily structure, so we’d say cork underlayment is remarkably effective.
Bear in mind that STC doesn’t evaluate frequencies below 125 Hz, so it’s not a good metric if you’re trying to eliminate bass.
NRC of Cork
Noise reduction coefficient, or NRC, is measured in decimals between zero and one. Cork products vary in terms of NRC, with some 1-inch thick wall tiles rated at 0.7 and some cork bricks rated at just 0.15.
This measure can be viewed as a percentage, where 0.7 equals 70%. At that level, an average of 70% of the sound is absorbed, while the remaining 30% is reflected.
R-Value of Cork Underlayment
While the R-value typically focuses on heating insulation, it’s still a good number to keep track of. Various vendors rate their cork underlayment with R-values in the 1.125 to 1.5 range, meaning that cork underlayment is nearly as insulative as wool carpet. It’s a great substance for keeping the warmth in and the cold out.
Of course, its usefulness for heating isn’t why we included R-value on this list. R-value has a soundproofing angle as well. The higher the number, the greater the sound absorption.
This makes sense if you understand what happens in soundproofing: there’s no such thing as making a surface impervious to sound. What you’re really doing is installing substances that convert that sound to heat. So it stands to reason that a material that absorbs heat rather than lets it pass through will do the same with sound.
Types of Cork Soundproofing Products
There are at least six types of cork soundproofing products in use today. Below, we’ll explain each type.
We mentioned earlier that not every type of cork product produces the same amount of sound reduction. Be aware that various types of cork treatments reduce differing levels of sound and in differing frequency distributions.
1. Cork Board Soundproofing
Corkboard is the soft pushpin-holding stuff you find in offices and classrooms the world over. It’s more porous than some of the more acoustically designed products below, but it still offers acoustic and thermal benefits when used on walls.
When used for soundproofing, the thickness is everything. The thickest conventional cork wallboard we’ve found in large panel sizes is this half-inch thick 4' x 8' cork boards from Manton.
As an added bonus, by using it in your acoustic space, you’ll also instantly gain a place to tack up papers, reminders, notes, or whatever else. Seriously, in a DIY recording space, this advantage could prove surprisingly useful.
2. Soundproofing Cork Tiles
Like a cork board, cork tiles are typically advertised as a bulletin board sort of product, perfect for DIY building your own “inspiration wall” or some such thing. Sure, go for that if you want, but we’re really here for the soundproofing.
|Premium Cork Tiles 12"x12" - 1/2" Thick Cork Boards for Walls - 4 Pack - Ultra Strong Self...||Amazon|
Most cork tiles aren’t custom-designed for soundproofing, but they have all the same properties as the larger cork boards. The only real difference is size: these 12 are easy to configure in just about any space. Stick them to the walls and ceiling to reduce the intensity of midrange frequencies. You can also space multiple cork tiles out in an effort to address specific trouble spots.
3. Acoustic Cork Underlayment
Acoustic cork underlayment is a thin sheet-like layer of cork designed for noise reduction in floors. It goes between the subfloor or slab and the “finished” flooring product (hardwoods, vinyl tile, and so forth). Hands down, this is one of the best ways to soundproof a floor. As such, it’s very popular in multilevel residential buildings like apartment and condo towers.
|QEP Natural Cork Underlayment Roll - 1/4" (6 mm) - 200 sq. ft., 48" x 50' (72000Q) , Brown||Amazon|
It certainly has its uses in studio and home theater type applications as well. If your music space is above another room, investing in quality acoustic cork underlayment like this one from QEP is a no-brainer.
Remember as well that cork is a relatively soft, warm material. In addition to its soundproofing benefits, a cork underlayment will help to soften and warm your floor underfoot.
4. Acoustic Cork Flooring
Not only can cork be used as an underlayment, but it can also be used as the finished flooring product itself. Cork flooring looks amazing, and these days it can come in all sorts of premium finishes that don’t look much like cork. We like this option from Forna, which retains some of the character of cork without looking like you put a bulletin board on your floor.
Cork flooring does reduce noise, with some cork floor tiles receiving a .15 NRC. That’s a lot lower than thick cork wall tiles, but it’s more sound absorption than many harder floor types can offer. However, because the finished flooring tiles must be sealed to be functional, they lose some of their effectiveness.
|Berber Forna 1/2" (12mm) 12"X36" Uniclic Floating Cork Flooring 17.44 SF/Box Environmentally...||Amazon|
There’s a lot to love about cork flooring: it feels soft, it insulates well, and it even has antimicrobial properties. However, there are some notable drawbacks as well. It’s decidedly not pet-friendly because it scratches and dents easily. Heavy furniture can sink into the cork, creating divots that don’t go away. It can also fade in sunlight more aggressively than harder woods.
What does all this mean for audio applications? While you wouldn’t want it under your heavy recording console, cork flooring could be a perfect option for the open floor space you use for playing or singing.
5. Cork Acoustic Panels
Sometimes you need to place or hang acoustic panels in space to tame the sound, especially in smaller rooms. If you don’t like the idea of using acoustic insulation for this purpose, cork can work well. You’ll want to get the thickest you can get, like these half-inch cork panels from Cougar Cork.
|Premium Cork Board Tiles 12"x12" - Extra Thick 1/2" - 40 Bonus Push Pins - Self Adhesive Backing -...||Amazon|
Sticking two together to form a 1-inch tile is an option. It won’t double the sound reduction, but it will increase it significantly. These panels are easy enough to hang just as they come, or you can frame them for an aesthetic boost.
6. Cork Sound Insulation
Several of the above products, while useful for soundproofing, aren’t purpose-built for it. In contrast, cork sound insulation, like the products from ThermaCork, is precision-engineered to reduce even more sound across a broader spectrum of wavelengths. Check out the link to see the specific frequency maps for some of ThermaCork’s products.
ThermaCork is designed for commercial customers more than DIYers, and many products are designed to be installed during new construction. That said, installation of their cork insulation boards is not difficult, as long as you have access to the place you want to install them.
Conclusion – Is Cork the Right Material for You?
We hope that, after learning quite a bit about cork soundproofing, you have a better understanding of “nature’s acoustical foam.” But in the end, is it the right material for you?
If you’re looking for near-absolute isolation from especially bass-heavy music or media, then cork alone isn’t going to cut it. (That said, most products won’t. Bass is very difficult to stop, even with air-gapped concrete.) The same goes if you’re trying specifically to dampen or eliminate very high frequencies.
But if your soundproofing needs are mostly midrange, like the human voice (speaking or singing) and instruments in similar ranges, cork is worth a look. It’s an effective, affordable, aesthetically pleasant, and eco-friendly choice. The same goes for those of you whose soundproofing needs are more practical than audiophile in nature (think noisy upstairs neighbors). In a home renovation context and as a floor underlayment treatment, cork can hardly be beaten.
*Last updated 2021-07-28 at 08:32 / Product Links & Images from Amazon Product Advertising API