If you have ever lain awake at night listening to the sounds of footsteps in the flat above you, your neighbor needs to install underlayment. If you are tired of the noise, your feet make when walking around your house, you should consider an underlayment. What, then, is underlayment?
Underlayment is the layer of material (this could be cork, rubber, foam, felt, etc.) between your subfloor and flooring. Good underlayment increases the lifespan of your flooring by protecting it from friction and improving the floor’s overall performance. An underlayment can improve the acoustic ratings and benefits of your flooring, and it can bring great comfort to you and anyone who stands or walks on your floor.
Now that you know what underlayment is and have an idea of its purposes, you need to know which is suitable for you. This article presents two types of underlayment: cork and rubber underlayment. It highlights the differences and similarities between the underlayments to help you choose what is best for you.
Rubber underlayment does a better job at sound control than cork underlayment does; in fact, you would ordinarily need cork underlay to be 30% thicker than rubber underlays to achieve the same results. Rubber underlayment is made from recycled tires, so it does not compress under lots of weight; it returns to its standard shape after the weight is removed. It does a better job at this than cork underlayment.
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| Cork Underlayment | Rubber Underlayment | |
| Prices | Cork underlayment is generally less expensive than rubber underlayment. But this also depends on its thickness, features, and how it is constructed: in rolls or sheets. Cork underlayment can cost anywhere between $0.50 to $1.50 per square foot. | Rubber underlayment is one of the most expensive underlayments in the market. Good rubber underlayment can range from $1 to $6 per square foot. |
| Material | Cork underlayment is made from the bark of cork oak trees. It provides natural protection against mold and mildew. It is 100% natural and eco-friendly, and the trees are not harmed if the cork is harvested professionally. | Rubber underlayment is oftenmade of recycled, pulverized rubber tires, contributing to sustainability. Some rubber underlayments incorporate certain anti-microbial ingredients that prevent the growth of mold, mildew, algae, and bacteria. This function is helpful under concrete slabs or moisture-prone areas such as a basement. |
| Smell | The bark of a cork tree has an earthy, sawdust smell, but this dissipates over time. High-quality cork underlayment may come with that smell, but it goes after a few days. | Rubber underlayment may emit odors, especially when the sun heats the flooring above it. As it deteriorates, rubber underlayment emits toxic fumes. |
Differences Between Cork and Rubber Underlayment
The significant differences between cork and rubber underlayment lie in the quality of sound reduction and price.
Sound Reduction
Rubber Underlayment
The Sound Transmission Class (STC) measures the efficiency of soundproofing and how much sound transmits through floors, doors, windows, etc. Rubber underlayment does an incredible job in absorbing sound and preventing the transmission of hollow sounds caused by foot traffic and impact sounds caused by construction. Rubber underlayment offers a tremendous amount of sound reduction compared to cork underlayment.
| Thickness | STC |
| 3mm (1/8″) | Up to 50 |
| 6mm (1/4″) | Up to 55 |
| 9mm (3/8″) | Up to 56 |
| 12mm (1/2″) | Up to 58 |
It is important to note that doubling the thickness of your rubber underlayment does not equal double the sound absorption. The table above shows that the STC of 6mm rubber underlayment is not double of 3mm.
Cork Underlayment
The cellular structure of cork is similar to memory foam. When you apply pressure on it, it folds to that pressure, but it returns to its original state when you remove the pressure. This works towards reducing sound transmission from the flooring. Compared to rubber underlayment, cork underlayment is not as efficient at sound reduction.
| Thickness | STC |
| 6mm (1/4″) | Up to 50 |
| 12mm (1/2″) | Up to 53 |
Similarities Between Cork and Rubber Underlayment
Eco-Friendly
Cork and rubber underlayment are eco-friendly, recyclable materials. Cork underlayment is made from the bark of a cork tree. Although, rubber underlayment may give off petroleum-like smells as it deteriorates. On the other hand, rubber underlayment is often made from recycled tire rubbers, contributing to sustainability.
Comfort
Underlayment provides comfort to your feet as you stand and walk on flooring that it cushions. Regardless of their respective sound absorption and reduction capabilities, cork and rubber underlayment provide premium comfort to your feet.
Longevity of Flooring
The natural resistance of cork and rubber underlayment to pressure from foot traffic, heavy objects, and other kinds of pressure ensure the longevity of your flooring. This resistance prevents the possibility of permanent dents and marks on your flooring from continuous, persistent pressure. Underlayment prevents friction between flooring and subfloor, further increasing the lifespan of your flooring.
Conclusion
Cork and rubber underlayment have similarities and differences that may influence your decision to buy either of them. But it mostly boils down to this: rubber underlayment is a lot more expensive than cork but has higher sound reduction capability. At the same time, it might produce odor as it deteriorates, so its lifespan may not be as long as that of cork underlayment. But cork underlayment are relatively cheaper than rubber underlayment, and they do not deteriorate as quickly as rubber underlayment.
In other aspects, they are similar. They are both eco-friendly, cork more so than rubber. They provide comfort to your feet, which is a significant factor, especially if you spend much time indoors. If you are sensitive to odors (for example, if you are asthmatic, have migraines, have latex allergies, etc.) and want a cheaper underlayment that does a good job reducing sound transmission, you should purchase cork underlayment. But if you can afford to buy rubber underlayment and do not mind any potential odor, you can buy rubber underlayment. Or if you do not mind the possibly limited lifespan of rubber underlay so that you can get a top-notch sound reduction.