Top 7 Best Underlay for Soundproofing for All Floor Types

As I sit here in my cozy home office, the cacophony of life outside seems to conspire against my peace and quiet. Whether it’s the neighbor’s lawnmower, the distant hum of traffic, or even the pitter-patter of my mischievous cat’s paws on the hardwood floor, unwanted noise creeps into our lives when we least expect it. That’s when it hit me: I needed a solution to reclaim my sanctuary and turn my home into an oasis of tranquility.

My quest for serenity led me down a rabbit hole of soundproofing options, from acoustic panels to heavy curtains. But as I delved deeper into the world of noise reduction, one crucial element kept resurfacing—underlay. A good underlay can make all the difference in the battle against unwanted noise, whether trying to create a peaceful haven in a bustling city or simply enjoying a quiet movie night without disturbing the rest of the house.

In this blog post, I’ll take you through my research and experiences as I explore the best underlay for soundproofing.

What is Flooring Underlayment?

Flooring underlayment, which serves as the layer between the floor covering and the subfloor, enhances the value of commercial flooring systems in several ways. Underlay provides the necessary cushioning to alleviate foot fatigue, offers dimensional stability, allows for installing flooring over minor imperfections in the subfloor, and, in many instances, possesses a high R-value that contributes to a building’s thermal insulation.

However, one of the most crucial challenges underlayment addresses is the reduction of sound transmission within a building. Architects and designers frequently incorporate specific underlayment types, known as acoustic underlayment, alongside acoustic ceiling and wall systems to effectively soundproof buildings.

The efficiency of a flooring system in preventing the transmission of impact noise is evaluated using a metric called the Impact Insulation Class (IIC). A higher IIC indicates greater effectiveness in isolating impact noise. The IIC is determined through laboratory testing, which involves striking a flooring system with a specialized “hammer machine” and measuring the resulting sound heard in the floor below.

A flooring system not designed for impact sound isolation may have a relatively low IIC, such as 30. Conversely, a flooring system specifically engineered to enhance acoustic performance can achieve an IIC rating of 70 or even higher, as stated in Architectural Acoustics Illustrated.

Types of Soundproof Floor Underlayment

To select the appropriate underlay for soundproofing your floor, it’s essential to clarify the following:

• Are you aiming to prevent airborne noise or reduce impact noise?
• What kind of flooring will be placed over the underlay?

Solid Soundproof Underlayment: For airborne noise

Thick/Heavy: These are the primary attributes enabling your flooring to block airborne noises effectively. Suitable materials for sound blocking include an Oriented Strand Board (OSB), Medium-Density Fiberboard (MDF), or Mass Loaded Vinyl (MLV) or cement board.

If you need to address low-frequency sounds like bass music, I suggest incorporating a damping compound like Green Glue. It should be applied between two rigid layers, such as two OSB boards, to ensure its effectiveness. When sound excites these two layers, the damping compound absorbs the sound waves and converts them into heat, effectively mitigating low-frequency noise.

Use resilient soundproof underlayment for impact noise.

Most floor underlays are composed of resilient materials, which are the most proficient at countering impact noises. These materials can absorb and diminish soundwaves, particularly those in the mid and high-frequency range. Resilient materials are typically not very dense or thick, yet they introduce a decoupling effect that aids in dispersing the sound energy traveling through your home’s structure. Examples of resilient materials include rubber, foam, fibers, and cork.

What to Consider when Choosing the Best Underlay for Soundproofing

Sound Transmission Class (STC)

Soundproof underlays often feature the acronym “STC,” which stands for Sound Transmission Class.

The STC rating is a standardized measurement conducted in laboratories to evaluate the ability of a material to decrease airborne noise. This measurement involves assessing the reduction in sound intensity, measured in decibels (dB), between two rooms. The material is typically applied to the wall or floor that separates these two spaces. The greater the reduction in sound intensity, the more effective the material is at noise reduction, resulting in a higher STC rating.

Building codes typically mandate that wall or floor assemblies achieve an STC rating of up to 50 to meet minimum soundproofing requirements. While not a perfect measure, the STC rating is a valuable means of gauging a material’s capacity to block airborne sounds.

Materials

When considering the purchase of the best soundproof underlayment, it’s essential to consider the material of the underlayment itself. The choice of material plays a significant role in determining its suitability for use with nail-down hardwood flooring. Soundproof underlayments are available in various materials, but this guide will focus on four primary options: rubber, foam, cork, and felt.

a)Rubber

Rubber holds excellent potential for sound transmission blocking due to its flexibility. It can effectively absorb noise and vibrations, making it suitable even for flooring that requires nailing down. Rubber underlayments are relatively straightforward to install and offer protection for wooden flooring, given their water-resistant properties.

b)Foam

Foam underlay can contribute to the reduction of both airborne and impact noise when used with nail-down wood flooring. Furthermore, foam underlayment diminishes the echoing effect of footsteps caused by the inherent hollowness of wooden flooring. Many foam underlays also incorporate a vapor barrier, making them suitable for those who prioritize moisture protection.

c)Cork

Cork underlayments can absorb sound energy, although they are not commonly employed solely for soundproofing. One of the notable advantages of cork underlay is its eco-friendly nature and antimicrobial properties. Moreover, cork underlayment aids in smoothing out uneven flooring surfaces. However, it’s essential to note that while cork underlay is ideal for soundproofing, it does not offer moisture protection.

d)Felt

Felt is an effective choice for sound control and moisture protection regarding flooring. It happens to be the most prevalent underlayment material for hardwood floors. Incorporating a felt underlayment can securely nail down wooden flooring while enhancing its soundproofing properties.

IIC Ratings

IIC, which stands for Impact Insulation Class (IIC), is essentially the counterpart of STC but for impact noise. Simply put, IIC measures a material’s effectiveness in reducing impact sounds. This rating is established through laboratory tests where a tapping machine is used in one room. The sound levels generated by the tapping machine in the room are recorded and converted into an IIC rating. A higher IIC value indicates the material is more proficient at absorbing and reducing impact noises.

In contemporary building codes, there is typically a requirement for a minimum IIC rating of 50 to meet soundproofing standards.

• How to stop vibrations through floor?

IIC and STC Rating Limitations

IIC and STC, as determined in laboratory tests, come with the following limitations, and it’s important to consider these factors:

Differences in Floor Assembly Composition: The composition of the floor assembly in a laboratory setting may not precisely mirror that of your actual home. This disparity can lead to variations in noise transmission behavior between lab testing and your specific flooring.

Frequency Range Limitations: IIC and STC ratings do not encompass frequencies below 100 Hz and 125 Hz, respectively. This means that these ratings do not fully consider sounds falling below these frequencies, such as footsteps, traffic rumble, aircraft noise, and construction machinery. To gain a more comprehensive understanding of sound control, it’s essential to consider these lower-frequency sounds that can significantly impact your acoustic environment.

Variability Across Manufacturers: Lab testing of floor assembly composition can vary from one manufacturer to another. Consequently, these discrepancies can make comparing STC/IIC values across different manufacturers challenging.

Best Underlay for Soundproofing Reviews

1. QuietWalk 360 Sq. Ft. Laminate Flooring Underlayment

• Suitable for use: Laminate / Engineered Wood / Solid Wood / Rigid Core Vinyl / WPC / SPC / LVT (with a thickness of 5mm or greater)
• Compatible Subfloor Types: Concrete / Wood Subfloor
• Installation Methods: Floating / Glued / Mechanically Fastened
• Composition: Made from Recycled Fibers
• Thickness: 3mm
• Sound Ratings: STC: 71 – IIC: 66 – ΔIIC: 22

QuietWalk’s 360 Sq. Ft. underlayment provides effective sound protection for laminate floor installations and can be applied to a wide range of wood flooring types, including vinyl plank and nailed-down hardwood. Moreover, it is crafted from recycled materials, ensuring a safe and eco-friendly installation for your building.

Using recycled fibers allows for airflow within the felt, while the underlayment has a vapor barrier preventing moisture accumulation. It holds a Greenguard certification, signifying the absence of harmful VOC emissions. Additionally, it is approved for use with radiant heating systems installed beneath the floor.

QuietWalk’s 360 Sq. Ft. underlayment boasts an impressive IIC rating of 71 and an STC rating of 66, making it highly effective in noise reduction. Its ease of installation further enhances its appeal.

Pros:

• Simple installation process
• Excellent at reducing noise
• Compatible with a wide range of wood flooring types
• Greenguard is certified for low-emissions

Cons:

• It can be somewhat challenging to cut

2. Roberts Super Felt Cushion Underlayment Roll

• Designed for use with Laminate / Floating Engineered Hardwood Floors
• Suitable Subfloor Types: Concrete / Wood Subfloor
• Compatible Installation Methods: Floating / Glued / Mechanically Fastened
• Material Composition: Made from Recycled Fibers
• Thickness: 3mm
• Sound Ratings: STC: 66 – IIC: 67 – ΔIIC: 21

The Roberts Super Felt Cushion Underlayment is a dependable choice when you have engineered or laminate flooring. It can also be applied on concrete floors, providing excellent insulating properties. This underlayment is particularly effective if converting a garage into a room. It also features a plastic film layer for added moisture protection, with the unique ability to absorb sound rather than reflect it.

The Roberts Super Felt Cushion Underlayment boasts an IIC rating of 67 and an STC rating of 66, demonstrating its effectiveness in sound absorption and reduction. For reference, the International Building Code stipulates that both ratings should be at least 50. At the same time, municipal and HOA codes require STC and IIC ratings of 60 or higher for multi-unit structures. This underlayment, with ratings surpassing 60, excels in soundproofing.

The underlayment is dense and 4mm thick, crafted from recycled felt material. It’s worth noting that the moisture barrier should be handled with care as it can tear easily.

Pros:

• It provides additional moisture protection
• Absorbs sound instead of reflecting it
• Easy installation
• Ideal for use with engineered or laminate flooring.

Cons:

• The moisture or vapor barrier is susceptible to tearing.

3. Natural Cork Underlayment

• Suitable for use with Laminate / Floating Engineered Hardwood Floors
• Compatible Subfloor Types: Concrete / Wood Subfloor
• Applicable Installation Methods: Floating / Glued / Mechanically Fastened
• Material Composition: Made from Recycled Fibers
• Thickness: 3mm
• Sound Ratings: STC: 66 – IIC: 67 – ΔIIC: 21

This natural cork underlayment is a highly favorable material to work with. It is twice as thick as the previously reviewed material, so it’s essential to carefully consider whether 6mm might pose any challenges in your flooring project. The advantage of this extra thickness is its enhanced ability to absorb irregularities in the floor surface.

As a soundproof underlayment, natural cork performs admirably in reducing impact noises, achieving a Delta IIC rating of 22, which is commendable.

Cork also possesses excellent thermal properties, contributing to reduced heat transmission. However, it’s worth noting that it lacks a vapor barrier.

Regarding installation, cork can be somewhat delicate and prone to crumbling if not handled carefully, so it’s essential to account for potential material losses. Nevertheless, it is straightforward to cut and assemble.

I appreciate the tactile qualities of cork material. Although it comes at a higher cost than traditional fiber and foam-based acoustic underlayments, it is a user-friendly material.

PROs:

• Excellent sound-dampening properties (Delta IIC 22)
• Effective thermal insulation
• Easy to cut and install

Cons:

• Lacks a vapor barrier
• Higher cost compared to conventional fiber and foam-based acoustic underlayments

4. FloorMuffler UltraSeal Underlayment

• Designed for use with Laminate / Engineered / Solid Hardwood Flooring Systems
• Compatible Subfloor Types: Concrete / Wood Subfloor
• Applicable Installation Methods: Floating / Glued Down / Mechanically Fastened
• Material Composition: Foam
• Thickness: 2mm
• Sound Ratings: STC: 73 – IIC: 74 – ΔIIC: 25

The FloorMuffler 300SF Ultra Seal Underlayment offers several advantages for your flooring needs. It is 100 percent recyclable, adheres to low-VOC content guidelines, and provides various installation options to enhance the flexibility of your flooring project. Additionally, it utilizes closed-cell polypropylene foam to achieve exceptional noise absorption and acts as an effective moisture barrier to prevent mold and mildew growth.

Despite being 2mm thinner than its competitors, the FloorMuffler 300SF Ultra Seal Underlayment excels in noise absorption, surpassing its competitors in STC and IIC ratings. Furthermore, it includes a built-in vapor barrier, reducing the installation time and effort required.

This underlayment delivers top-notch acoustic performance, making it the ideal choice for noise reduction at a reasonable price. It stands out as the best underlayment for laminate flooring.

Pros:

• Offers the best acoustic performance available
• Thin profile (2mm)
• Includes a vapor barrier
• Versatile and compatible with most flooring types

Cons:

Slightly higher cost compared to alternatives

5. 3in1 Silent Vapor Barrier

• Designed for use with Laminate / Floating Engineered Floors
• Compatible Subfloor Types: Concrete / Wood Subfloor
• Applicable Installation Method: Floating / Taped
• Material Composition: Foam
• Thickness: 2mm
• Sound Ratings: STC: 66 – IIC: 64 – ΔIIC:

The last entry in our soundproof underlayment review is a cost-effective option. This material possesses nearly all the characteristics of its competitors, including the inclusion of a vapor barrier. Despite my inquiry, it boasts an IIC rating of 64 (though the manufacturer hasn’t provided a ΔIIC) and offers ease of cutting and installation.

In my assessment, it slightly lags behind its competitor regarding sound absorption properties but matches its performance in all other aspects. This material is worth considering if you’re working with a tight budget. However, it’s important to note that the pricing is based on orders for ten rolls of 100 square feet each. The lower cost may also be attributed to minimal advertising efforts, as some technical details are not as comprehensive as those of its competitors.

Pros:

• Acceptable sound-dampening properties
• Easy installation
• Includes a vapor barrier
• Affordable price

Cons:

• Requires purchasing in larger quantities
• Limited technical information provided by the manufacturer

Editors Pick: Best Underlay for Soundproofing

As you’ve likely learned from the information above, your decision ultimately boils down to several key factors:

• The type of flooring you have (wood, laminate, tile, LVT, carpet, etc.)
• Your specific requirements (airborne noise reduction, impact noise reduction, vapor barrier, etc.)
• Your budget constraints

In my personal preference, I lean towards using a 3in1 Silent Vapor Barrier for rooms with lower foot traffic, such as guest rooms, storage areas, or dressing rooms. However, I wouldn’t hesitate to invest a bit more when it comes to areas with higher activity levels, like the living room, kitchen, or children’s bedrooms. In such cases, my top choice would be FloorMuffler UltraSeal, which stands out as the most effective underlayment for soundproofing.

Keep in mind that the principles of soundproofing apply to walls, floors, and ceilings alike. I hope this guide has proven helpful in creating a quieter and more peaceful home.