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All You Need To Know About Laminate Flooring Underlayment

All You Need To Know About Laminate Flooring Underlayment

Here at Bestlaminate, we are often asked many questions about laminate flooring. With so many features to choose from, it can sometimes be difficult to determine which underlayment is the best option for your project. Perhaps your laminate flooring has underlayment pre-attached, what then? Do you need to put any additional layers underneath? Or maybe you have a radiant heating system and would like to know if it is okay to cover it with a foam underlayment. Our flooring experts have put together some answers to these questions. We hope this will help you decide which underlayment is best for your project.

What Is Underlayment?

Put simply, it is a thin foam pad, often made of polyethylene or polypropylene, which is laid on the sub-floor before installing the laminate. Most laminate floors on the market today require an underlayment to be installed. While there are manufacturers who offer floors with an underlayment attached, this is a special feature and is not included in most products.

Which Underlayment should I use?

Laminate flooring underlayment is available is a wide variety of styles.

Why Is It Necessary?

Having underlayment underneath your laminate flooring is essential, because it allows the floor to float. Laminate flooring is not nailed or glued down, so it needs some form of support. Think of it like a large jigsaw puzzle, which will be expanding and shifting as the climate changes. To avoid any damage due to friction between the laminate and your sub-floor, the underlayment must be laid first to give the laminate a smooth surface on which to float.

How to Install 3in1 Vapor Barrier Underlayment

Which Underlayment Should I Use?

While the concept of underlayment seems simple enough, all laminate underlayments are not created equal. Different manufactures offer many different features, which can enhance the feel and performance of your laminate floor. To help you figure out which underlayment will meet your needs, we have put together some more information on the underlayments that we offer. Before reading on, first ask yourself these two very important questions:

1. What Is Your Sub-floor?

If you are installing laminate over a concrete sub-floor, it is very important that a vapor barrier is used to prevent any possible damage due to the moisture released by the concrete. This is simply a sheet of thin plastic material, like Visqueen Vapor Block, that will stop any moisture from being absorbed into the laminate core. Many of the underlayments from Bestlaminate offer 2-in-1 or 3-in-1 underlayments, which include a vapor barrier as well as padding. This saves you the time and money associated with installing a separate vapor barrier.

How To Install 2in1 Vapor Barrier Floor Underlayment: Inspect your subfloor

2. Is This A Second Floor Installation?

If you are installing your laminate floor in an apartment, condo, or on the second floor of your home, you may want to consider an underlayment that offers noise reduction. Many apartments and condo associations require a minimum sound rating from the underlayment. While laminate flooring is quiet to walk on, noise can easily be transferred to the floor below without the proper underlayment. Choose an underlayment, like Floor Muffler or Roberts Super Felt, that gives a high sound reduction rating.

Floor Muffler Ultraseal 2mm Underlayment

Floor Muffler Ultraseal 2mm Underlayment

What If My Laminate Has Pre-Attached Underlayment?

If your laminate flooring already has underlayment attached, you would not use another underlayment. Adding extra padding can cause your locking system on your floors to break because there is too much cushion. The underlayment attached is meant to save you time from installing underlayment. However, if you are installing above a concrete sub-floor, you should install a thin vapor barrier that does not have extra padding to keep moisture from damaging your floor.

Pre-attached Underlayment

Underside of Laminate Flooring Showing Attached Underlayment

Important Underlayment Terms

When reading the specifications of underlayment, you may come across terms like IIC and R-Value. These terms may leave you scratching your head. But don’t worry! Here are the most common underlayment terms explained!

STC & IIC

While looking at underlayment for your laminate floor, you may come across STC/IIC with a number next to them. What exactly are these and what do they mean? Put simply, these are ratings that tell you how well the underlayment will dampen sound. The higher a number is following these letters, the less noise will be transmitted. The effect of this is mostly noticeable in rooms underneath the room in which the underlayment and laminate are installed. This is why many apartment buildings, commercial offices buildings, and condo associations require a minimum rating where sound is concerned.

The Sound Transmission Class (STC) and Impact Isolation Class (IIC) ratings are measured in decibels reduced for certain types of sound. The STC rating pertains to airborne noise, such as voices, radio, television, etc. The IIC rating measures impact sounds, such as footfalls, dropped objects etc. The transmission of these sounds through floor/ceiling assemblies (such as those found in multi-level homes and apartments) will be inhibited by underlayments with higher STC and IIC ratings. The International Building Code (IBC) states that all multi-family buildings must have a minimum sound insulation rating of STC 50 and IIC 50.

Thermal Ratings

In addition to the STC and IIC ratings, some underlayments may also have a thermal rating, or R-value. This refers to the underlayment’s ability to conduct heat. The higher an R-value is, the less heat will move through it. Many homeowners prefer an underlayment with a higher R-value to keep their feet warm in the winter months, however, if you have any kind of radiant heat system, a high R-value can inhibit its effectiveness.

R-values are measured in ft2*°F*hr./BTU, where °F is equal to the difference in temperature (in degrees Fahrenheit) between one side of a material and the other. An underlayment which has a value of 3 ft²*°F*hr./BTU will typically be represented as R-3. To put this in perspective, the typical R-value of a bat of fiberglass insulation is R-3 to R-5. Many polyethylene foam products have an R-value of 2-3, such as laminate flooring underlayments.

The Different Types Of Collections

Basic Underlayments

First up is our series of basic underlayments. These are the most simple, cost effective underlayments we offer at Bestlaminate. All three of the basic underlayments are suitable for most installations, though they do not offer many features. These are the most popular choices with contractors, due to their low price and effectiveness in allowing the laminate floor to float.

Standard Underlayment

The most basic option will be the standard underlayment. This is a great option for installing over plywood or oriented standard board (OSB) sub-floors, where a moisture barrier is not required. The Standard Underlayment will absorb minor imperfections in the sub-floor, giving your laminate floor a smooth, even surface on which to float.

Standard Underlayment

Standard Underlayment

2-in-1 Vapor Underlayment

Bestlaminate’s 2-in-1 Vapor Underlayment is another great option for basic installations. Made from the same low-density 3mm polyethylene as our standard underlayment, the 2-in-1 has the added protection of an attached moisture barrier film. This makes it a safe choice for installing your laminate floor over concrete sub-floors. Like the Standard Underlayment, this material will fill minor imperfections in the sub-floor, giving your laminate floor a smooth, even surface on which to float.

2in1 Vapor Barrier Underlayment

2in1 Vapor Barrier Underlayment

3-in1 Vapor Underlayment

The third option in Bestlaminate’s series of basic underlayments is the 3-in-1 Vapor Underlayment. Another polyethylene foam, this one is only 2mm thick, making it better to use under thinner planks. Unlike the Standard Underlayment and the Vapor 2-in-1, the 3-in-1 comes in pre-packaged rolls of 100 ft². This underlayment also has the vapor barrier attached to it, and has the added feature of an adhesive strip.

Vapor 3-in-1 Blue Underlayment

Vapor 3-in-1 Blue Underlayment

All of these underlayments are low density polyethylene. While none of them have been subjected to sound or thermal testing, they do offer some sound reduction, and are suitable to use over radiant heating. The Standard Underlayment and 2-in-1 Vapor Underlayment do not come in pre-packaged rolls, and can be cut for custom orders, making them a great choice for anyone who does not want to purchase an extra roll to get that few extra feet2.

Silent Collection

Next up is our series of silent underlayments. These are the next tier up in underlayments that we offer at Bestlaminate. All five of these silent underlayments are suitable for most installations where sound dampening is key. Some of these underlayments also have vapor barriers attaches, so be sure to look for these as you will get more bang for your buck if you’re installing over concrete subfloors. These are the most popular choices for people living in multi-family homes or apartments, or those who don’t want to hear their children banging around upstairs.

3in1 Silent Vapor Barrier Underlayment

If you’re looking for something that will help to muffle sound, but won’t break the bank, the 3in1 Silent Vapor Underlayment by Feather Step™ is a great option. This incredibly durable underlayment is a 2mm, cross-linked polypropylene, giving it a higher density than the open-cell polyethylene foam underlayments. Because of this, the Feather Step™ Vapor 3-in-1 absorbs sound and offers enhanced moisture protection. The attached foil moisture barrier works in conjunction with the foam itself to ensure that your floor is protected from any vapor given off by the sub-floor, and includes an adhesive strip for easy installation.

Vapor 3-in-1 Underlayment Silver

Feather Step 3-in-1 Vapor Barrier Silver Underlayment

ProVent Silent Vapor Barrier Underlyayment by Kronoswiss®

ProVent Silent Vapor Barrier Underlayment is one of the best values where laminate flooring underlayment is concerned. This polyethylene foam is 3mm thick and comes in pre-packaged rolls of 215 ft2. An attached vapor barrier protects against moisture, but it doesn’t stop there! ProVent underlayment is specially designed with micro ridges that, when walked on, actually pump moisture out to the sides of the room to vent out moisture. This underlayment is a great choice for any job – basements, first or second floor, apartments, condos, you name it! The Kronoswiss® ProVent can be installed over any type of sub-floor, and will absorb minor flaws, giving your laminate the proper surface to float.

ProVent Silent Vapor 3-in-1 Underlayment

ProVent Silent Vapor 3-in-1 Underlayment

Roberts® First Step ™

The First Step™ underlayment from Roberts® is one of the most popular choices in the laminate industry. Another great option for muffling sound, the Roberts First Step has an air flow layer which is similar to the Kronoswiss® Pro Vent. Polystyrene beads are substituted for a foam pad, allowing air to move freely through the underlayment to vent- preventing harmful mold and mildew build-up. This patented design also allows heat to be easily conducted, making this an excellent choice for sub-floors with radiant heat systems.

Roberts Silent 3 in 1 Vapor Underlayment

Roberts Silent 3 in 1 Vapor Underlayment

Floor Muffler® Ultra Seal

The Floor Muffler underlayment is the top of the line for sound reduction, with the highest STC/IIC ratings on the market. This makes it the number one choice for multi-family buildings around the globe. Similar to the Feather Step™ vapor 3-in-1 underlayment, the Floor Muffler® is made of a cross-linked polypropylene to give it more density. This directly contributes to its ability to cut down on unwanted noise. This also helps to block moisture, though it does not have a vapor barrier attached. The density of the Floor Muffler® underlayment keeps out any vapor released by your sub-floor, making it a safe choice to install over concrete subfloors.

Floor Muffler Ultraseal 2mm Underlayment

Floor Muffler Ultraseal 2mm Underlayment

Roberts Super Felt Premium Underlayment

Roberts Super Felt Premium Underlayment provides you with a superior sound dampening effects, insulation, and vapor barrier. This is superior choice for installation of laminate and engineered wood flooring. This underlayment is available in convenient rolls containing 100 square feet each. Durable and easy to install, comes with a tape strip to easily seal the rows of underlayment together.

roberts super felt underlayment

Roberts Super Felt Underlayment

Other Products

Visqueen – Vapor Block PE Film

Visqeen PE Vapor Block PE Film is not an underlayment, but simply a vapor barrier sheet that may be used as on concrete sub-floors. This is the perfect option if you are laying a floor which has a pre-attached underlayment on a concrete slab or any other stone floor where there is potential for moisture.

Visqueen 6Mil PE Vapor Barrier

Visqueen 6Mil PE Vapor Barrier

How To Select Laminate Flooring Underlayment

Installing Underlayment

Each underlayment is a little different and has their own manufacturer instructions. You must read the instructions to fully get an understanding on how to properly install. We’ve prepared a variety of installation tutorials that will give you graphical step-by-step guides on how to install your underlayment.

View them here: Flooring Underlayment Tutorials

Underlayment Tutorials

Final Thoughts

Below is a table with the specifications for all of the products listed above. Remember, not all of these products are subject to all of the same tests for sound or heat conductivity. Remember what to consider when choosing your underlayment- do you need something that is going to protect the laminate floor from harmful vapors? Or are you just on a plywood sub-floor and don’t need any special features? While higher R-values and sound ratings are appealing, they aren’t always necessary. We hope this will help you in your search for the right underlayment for your laminate flooring project.

Standard 2in1Vapor 3in1Vapor FeatherStep Provent Floor Muffler Roberts Visqueen
Width 40” 40” 46” 45” 40” 40” 40”
Contents 1720ft ²* 1720 ft²* 100 ft² 100ft² 215 ft² 100 ft² 100 ft² 100+ ft²*
Thickness 3mm 3mm 2mm 2mm 3mm 2mm 3mm 6mil
STC/IIC (db) NA NA NA 65/64 67/71 73/74 67/68 NA
R-Valueft²*°F*hr/BTU NA NA NA NA 2 3 2 NA
Tensile(psi) NA NA NA NA NA MD≥125 TD≥100 NA NA
Tear(lbs/ft) NA NA NA NA NA MD≥300 TD≥370 NA NA
Adhesive No No Yes Yes No Yes Yes No
Vapor barrier No Yes Yes Yes Yes Yes Yes Yes

* rolls are cut for custom quantity

Do you have more questions? Simply post it in our comments area. We will be happy to answer them all!

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Bestlaminate’s blog is dedicated to you by making the home improvement process easier and more affordable. Bestlaminate comes to the floor with you by providing DIY installation instructions which guide you step by step, saving you time and money. Bestlaminate’s team writes for you and provides details in wide variety of home improvement projects. We hope to make your home remodeling and maintaining a more positive experience.

21 comments

  1. Hello Alana. Thank you again for your prompt and informative replies. I am giving serious consideration to the 700 sf roll of the Muffler Underlayment, however I would like to know if a sample is available? I did read that samples of laminate are provided, however I didn’t note a request for underlayment.

    Thank you.

    • Alana Kane

      Hi Robert, you are welcome! I’m glad we could help. Yes, you can order samples of the underlayment. All you will need to do is fill out this form (http://www.bestlaminate.com/sample-request) with the underlayments you would like to see. Additionally to Floor Muffler, the Kronoswiss Provent is another great option for a radiant heat system. Once you submit the form, we will get the samples out to you right away.

  2. I pulled up a laminate floor installed by previous owner a few weeks ago that had a felt with vapor barrier underlayment on concrete subfloor. Discovered there was mold under it. So I now want to put the flooring back down with a new and hopefully better underlayment more suitable for Florida humidity. The vapor barrier was on top so the felt got damp from the concrete sweating and developed mold. What would you recommend for an underlayment. PS – I have moisture treated the floor and also applied concrete waterproofing in attempts to slow the moisture down as you would do for a garage floor.

  3. I am looking to install the Thermosoft radiant heating mats under 625 SF of Pergo laminate floor. I am in a high-rise condo with concrete slab flooring, so “downstairs” noise is not an issue. Thermosoft installation requires:

    1. underlayment (over concrete slab)
    2. Thermosoft heating pads
    3. moisture barrier
    4. Laminate flooring

    What type of underlayment do you suggest? What “R Value” would work best considering the heating element goes over the underlayment?

    thank you.

    • Alana Kane

      Hi Robert, thanks for your question! We would recommend using the Floor Muffler Ultraseal Underlayment. It is suitable for radiant heat and has a built in vapor barrier for over concrete subfloors. The R-rating describes the insulating properties, so the underlayment will help keep the heat from disbursing. The floor muffler is a good choice. Here are the details for the product: http://www.bestlaminate.com/floor-muffler-ultraseal-2mm-underlayment/. Let us know if you have any additional questions! Always be sure to check the manufacturer of both the floor and radiant heat system to make sure all of the materials are appropriate for installation.

      • Thank you for suggesting the Floor Muffler underlayment. As previously stated, I need to install an underlayment over slab concrete as the first step, followed by the Thermosoft Heating mats and then the Pergo Laminate. Your instructions forlaying the Floor Muffler says to lay a roll, then lay the laminate, lay another roll, then lay the laminate and so on. I was planning/hoping to lay the underlayment over the entire floor, then lay the heating mats, then the laminate. I cannot lay the heating mats one mat at a time. I need to lay the entire floor area. Can I still use the Floor Muffler?

        • Alana Kane

          Hi Robert – that is a great question! The reason they recommend this is just for ease of installation and helping to keep the underlayment flat. You can definitely lay the entire floor muffler down, as it tapes together at the seams. Hope that answers your question!

  4. Is there a difference in underlayment materials used for laminate floors, and those used with vinyl plank flooring? Or, can a single typ of underlayment be used under both types of flooring?

    Thank you

    • Alana Kane

      Hi Dave! Thanks for your question. With vinyl flooring, you do not need to use an underlayment. The material is thinner, so adding additional cushion can cause instability with the locking systems. If you are worried about moisture, you could use this vapor barrier film: http://www.bestlaminate.com/visqueen-6mil-pe-vapor-barrier-block/. Be sure to read the manufacturer instructions for any underlayment specifications. Let us know if you have any additional questions!

  5. What type of underlayment is recommended for all wood subfloor. We also live in a raised house. We had issues with the floor buckling due to moisture from using Premium Underlayment with 2mm polyethylene foam laminated with a vapor barrier. We may have to cut old wood floor and make subfloor dry plywood.

  6. Hi, i am having the same issues. We bought 12MM + 3MM padding Kingsington Manor laminate flooring from Lumber Liquidator. The salesman stated that we needed to buy the Bella premium underlayment for best results, sound proofing and heating and cooling bills. I am laying it in our main level of our house above the basement and it will be on plywood subfloors. It has carpet on it now but that is going to be removed and so is the carpet padding.
    Do I need to put down the Bella premium underlayment or not? It is ok and helpful to do so?

    • Alana Kane

      Hi David! Thanks for your question. Whenever buying a laminate with attached padding, it is not recommended to add additional underlayment to the subfloor. If it was being installed over a concrete subfloor, then we would recommend just a vapor barrier film. Adding too much custion under your flooring can effect the flooring stability and proper installation. Check out this article on the topic: http://www.bestlaminate.com/blog/can-i-install-underlayment-under-laminate-with-attached-padding/

      I do not know about the exact products you purchased, as we do not carry those, so I cannot give you 100% accurate advice. Be sure to read the manufacturer directions first! Adding additional underlayment can void warranties if the flooring was not installed correctly. Hope this helped!

  7. In the introduction of your discussion on underlayments you make the statement “Perhaps your laminate flooring has underlayment pre-attached- what then? ” but it is never addressed. Is it okay to use a felt Roberts underlayment if the laminate already has an attached underlayment?

    • Ashley Arndt

      Hi Craig! Great question! No, you would not use any underlayment if your laminate flooring has pre-attached underlayment. Adding unnecessary cushioning can actually be harmful to your floor. However, if you are installing over a cement sub-floor, you should lay down a vapor barrier, such as our 6mil Visqeen PE vapor block PE film, which does not have any extra padding. If you have any other questions, please don’t hesitate to ask!

      • If it does have the attached underlayment are there any other options I can use to address the potential sound issues?

        • Cork under pre-padded laminate possibly?

          • Ashley Arndt

            The thing you have to be careful with is creating too much flex underneath your laminate flooring. If you put too much padding, the floor won’t be stable and it could become damaged and void your warranty. First, I would check your floor’s manufacturer warranty and see if there are any recommendations. But, Cork or our Floor Muffler could work because it’s more rigid than a felt underlayment and it’s thinner so you won’t have to worry about under-cutting doors. I hope this helps you!

  8. Can I use the 6mm visqueen under a sound dampening underlayment? Is it necessary? The visqueen coming in at 6mm, as opposed the the other products offering only 2-3mm of moisture protection concerns me a bit. I’m installing a 12mm laminate flooring with a concrete slab.

    Thanks!

    • Viena

      Hi Jon!

      The Visqueen is used to add a layer of moisture protection when installing on concrete. Most sound dampening underlayments come with a preattached layer of film for moisture protection. As long as there is a film made for moisture protection, the thickness does not make a difference. Roberts Silent 3 in 1 (http://www.bestlaminate.com/roberts-silent-3-in-1-vapor-underlayment-630-sf.-roll/) underlayment is the best option because it provides sound reduction, moisture resistance and corrects minor subfloor imperfections.

      If you already have an underlayment that does not have a moisture protection film, it is okay to install Visqueen underneath. Be sure everything is flat and well secured together.

      I hope this answers your question. For additional info, feel free to call 1-800-520-0961.

      Have a great day!

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