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All About Underlayments: Purpose, Benefits & Install Tips

by Crystal Hosking - Hosking Hardwood Flooring, Inc. ©2013, Copyright Protected. All Rights Reserved

Underlayments play an important role during the installation of new hardwood flooring or laminate flooring. Whether you intend to staple down, nail down or float, an underlayment offers a slew of benefits during and after installation.

Staple or Nail Down Installation

With a staple down or nail down installation over a wood subfloor using solid flooring or engineered flooring, it is recommended that an underlayment of 15lb. black felt paper is rolled out over the wood subfloor prior to installing the new floor. This hardwood felt paper is necessary to greatly reduce the chance of any moisture coming up through the subfloor and will help protect the new hardwood flooring. Even if you think you don't need it and you're tempted not to use it, it's always better to be safe than sorry. Especially when being sorry could mean $1000's in damage. 15 lb. black felt paper is relatively inexpensive and can be the difference between warped hardwood flooring boards in the future or a floor that stays perfectly beautiful for a lifetime.

15lb. black felt paper for flooring installations over wood subfloors looks a lot like roofing paper, but it is very different. Roofing paper is typically coated with asphalt or tar, which will emit harsh chemical odors, especially if enclosed in your home. Therefore, it's important to make sure the 15lb. black felt paper you're using is manufactured specifically for hardwood flooring installations.

Installation of 15lb. black felt paper is incredibly easy and fast. Simply roll the black felt paper out over the plywood subfloor, overlapping the seams approximately 4 to 6 IN. and then use a hand stapler to attach to the subfloor.

Floating Installation

Underlayments pads are especially important for engineered floors or laminate floors which are installed via the floating method over wood or concrete subfloors. When you float an engineered or laminate floor, none of the boards are actually attached to the subfloor. An underlayment is necessary for multiple reasons, floating floors will expand and contract, moving ever so slightly as a whole unit. The smooth surface of the underlayment allows the flooring on top of it to move slightly during seasonal relative humidty changes. Underlayments are also are used under floating floors to act as a cushion, allowing for a bit of a softer feel when walked upon.

 

 

Some underlayments pads these days are made with an attached plastic moisture retarder. 4-6 mil Plastic moisture retarders are basically non-negotiable when it comes to installing over concrete subfloors, we always recommend the use of a moisture retarder over concrete subfloors. (For underlayments without a moisture barrier attached, you can always install a 6mil plastic sheet separately directly over the concrete slab.)

Underlayment pads also helps to even out subfloors which may have minor imperfections, which is important for a smooth floating installation process.

Lastly, some underlayments pads have exceptional sound absorption properties and can be used as a sort of sound insulator, preventing sound transfer.

There are a multitude of underlayments available for floating installations. They range from simple foam pads to foam pads with a plastic moisture retarders attached to dense felt-like underlayments with remarkable sound absorption properties. Foam pads are typically thinner and their sole purpose is to add a little cushion. Foam pads with moisture barriers attached are also on the thinner side but also offer that moisture protection. The denser underlayment pads (usually a felt like material) are typically a bit thicker and offer more support and insulation because of there dense nature. Please note... that "Regular Carpet padding" is too thick and soft to use as an underlayment pad for any wood or laminate flooring and could cause the joints of the flooring to break when walked on.  

Some hardwood and laminate manufacturers make their own underlayments for floating applications, which they recommend for use with their products. However, in most cases, any industry approved underlayment will get the job done. It's important, prior to installation, to read the specific flooring manufacturer's installation instructions. If they require use of their brand specific underlayment in order for their warranty to be effective, it's always a good idea to acquiesce. 

Installation of underlayment for a floating floor is very simple. Underlayments typically come in rolls. After subfloor prep, simply roll out the underlayment. Many underlayments these days have self-stick overlap flaps for connecting multiple sections of underlayment together. If the underlayment you are using doesn't have these, you can simply use duct tape to secure the edge of one portion of underlayment to the other. (Some flooring manufacturers will sell seam tape, but, really, duct tape works just as well.)

 

 is a dense felt-like material, using air-laid filaments. This product is renowned in the hardwood flooring industry as being one of the most advantageous underlayments for floating floors. Features of Silent Stride Underlayment include: sound absorption, moisture protection, minimizing of subfloor imperfections, insulation and anti-microbial properties. On top of all that, Silent Stride is pretty affordable when compared to similar products in its category (cork or rubber underlayments, which share some of the same properties). 

One of our top selling underlayments (shown above) isis a dense felt-like material, using air-laid filaments. This product is renowned in the hardwood flooring industry as being one of the most advantageous underlayments for floating floors. Features of Silent Stride Underlayment include:On top of all that, Silent Stride is pretty affordable when compared to similar products in its category (cork or rubber underlayments, which share some of the same properties).

 

Cork Underlayment

Cork underlayments are certainly gaining popularity over synthetic underlayments in both residential and commercial settings. But, what are the major benefits of using a cork underlayment? Cork is a natural product from a renewable source. If you're looking to go more "green" with your home, cork underlayment is a step in the right direction. Cork underlayment also has superior sound deadening qualities more than most any other synthetic underlayments previously mentioned it also helps minimizing subfloor imperfections, adds a degree of insulation and has anti-microbial properties. Many homeowners with allergies love cork as it is naturally anti-bacterial as well as anti-fungal. It's important to remember that cork is naturally water resistant, but not waterproof. Therefore, a 6mil plastic moisture retarder is recommended under the cork for installations over concrete slabs.

Cork underlayments can come in a variety of thicknesses. We've found that the most popular are the 1/8 IN. thick cork underlayment (3mm) and the 1/4 IN. thick cork underlayment (6mm). The only difference is the thickness, the thicker 6 mm will give you twice the sound absorption if desired to lessen any noise when the floor is walked on. Cork underlayments can come in either rolls or sheets. If an installer needs to add height to a subfloor, he'll often choose to use the thicker 1/4 IN. cork underlayment, as most synthetic underlayments measure up at about 1/8 IN. thick.

Cork underlayments are a bit different from other underlayments, because they can be used in staple/nail down installations, floating installations and even in glue down installations. If you plan on installing your flooring via a staple or nail down method with a cork underlyament, you can choose to either float the cork or tack it down to the plywood subfloor. For floating installs, you can either float the cork underlayment or you can tack it down to the subfloor; and then simply install the floating floor on top. If you choose to glue down your engineered hardwood flooring using a cork underlayment underneath you would need to glue the cork down securely to the subfloor and then you can glue the hardwood directly on top of that cork.

Laminate Flooring with Underlayment Attached

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All About Underlayments

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Steven

Date: May 10, 2022
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If we are installing solid oak hardwood floors on OSB subfloor do we need underlayment other than a simple plastic vapor barrier?

May 10, 2022

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RevW

Date: September 17, 2021
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Informative and useful, to the point

September 17, 2021

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Tony capili

Date: April 1, 2021
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Informationally good

April 1, 2021

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James Robinson

Date: March 19, 2021
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Thanks, I have been educated.

March 19, 2021

By:

Donnie

Date: March 15, 2021
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Im installing cork under nail down hardwood but Im hearing that it will crack overtime really bad. Is this true or not really?

Reply by HoskingHardwood : We have not had any problems with our cork underlayment.  They use cork in 100 year old wine bottles without any problems.

March 15, 2021

By:

Mvr

Date: March 14, 2021
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What can I put over top 6mm cork. I am told it is to flexible and click in Seams will break.

Reply by HoskingHardwood : We haven't had any problems with using a 6 mil cork underlayment under LVT its to firm to flex enough to cause problems with the thinner LVT. other softer underlayments are not recommended.

March 14, 2021

By:

Matt Early

Date: November 23, 2020
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Your article was very helpful I am currently installing hardwood over a wooden subfloor and also installing vinyl plank flooring over concrete subfloor. Your article address both issues and was very informative thank you

November 23, 2020

By:

Allan

Date: October 29, 2020
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I’m about to install engineered hardwood flooring in an old post and beam home. Subfloor is 3”x6” t&g decking with 7/16” OSB screwed on top. Was originally going to use a floating floor but will be nailing it down instead. I Purchased the mfg’s closed cell underlayment with a vapor barrier ($600) but they say it can only be used w/floating floors. It’s about thickness of RamBoard and doesn’t seem to compress. I’d still like to use it for sound deadening but they recommend AquaBar B moisture barrier with nails. Nails going through either product will defeat the purpose as a true “moisture barrier.” Why shouldn’t this underlayment be used with nails/cleats? I see you recommended using cork with nails but I can’t return this underlayment and would like to use it if possible.

October 29, 2020

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Jim Brady

Date: August 5, 2020
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Hi guys, I like the article and detail. Im looking to not remove my 40year old solid oak 9"parquet 3/8" thick that is black adhiesive glued down on slab. My wife would just like a different wood floor. We did pergo in our cabin over foam and is too clickedity clack loud. She selected a 3/8" hardwood that is hickory birch, 4", 7" wide. My plan is to 40grit sand and float with a fixall the only 20ft sq area that is 1/8" low. Then install 30lb flooring felt. The new floor has 1/8" bull nose, TandG and doesnt click/snap together. Must I 45 degree nail it down, (I dont think the oak will like it and slab is underneath). or instead use a 1/8" tooth trowel with adhesive. Floating it is my preference but it is a non snap floor. Would this be a bad choice and I must get snap together? Im fine with replacing the base and trimming doors. The only other thing is my kitchen is linoulem over slab. Im planning to use a liquid self leveler to get to the existing oak floor height then follow

August 5, 2020

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Bruce

Date: August 1, 2020
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Want more information on Felt Flooring Manufacturer? Feel free to contact us.

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I was not aware of cork as an underlayment. After reading this article I will be using cork.

August 1, 2020

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Felt fabric is believed to be amongst the oldest forms of fabric in existence. It’s unique in its construction, texture, and its numerous uses — ranging from clothing such as hats, coats, and boots, to crafting materials and, yes, even rug pads.

But what is felt really? We're glad you asked.

What is felt fabric?

Felt is a fabric made from natural or synthetic fibers that are interlocked or matted together. It’s mostly made from wool but it can also be made from synthetic fibers, such as acrylic and rayon (think yarn fibers).

In general, you’ve got three main categories of felt: natural fiber, synthetic fiber, and combined.

Natural fiber felt can come from cotton, animal fur, or wool. To create combined felt — you guessed it — you combine the natural with synthetic such as acrylic, nylon, or polyester.

However, felt is a bit more unique than you might think. Unlike most fabrics that are woven or knitted together, felt is made from a process that combines heat, moisture, and pressure to form an interlocked, durable fabric.

Origins of felt fabric

We don’t have much consensus on the origins of felt fabric — it’s THAT old. Most likely it originated in Asia several thousand years ago, where they used it to make tents and clothing.

Regardless of where felt came from, one thing is clear: felt has withstood the test of time. Basically, it was damn good back then, and it’s still damn good now.

How is felt fabric made?

Felt is made by applying heat, moisture, and pressure to fibers to interlock them into a durable fabric. The general method of making felt has remained unchanged over the years, but some differences do exist.

Here’s how people get it done these days (with wool). This is a kind of long process, so buckle in.

1. The wool is separated into its different colors — white, gray, or brown.
2. It’s then cleaned to remove debris caught in the wool. (Have you been up close to a sheep before? They are not the cleanest of animals.)
3. The wool is put into a machine that loosens and separates the clumps that naturally form.
4. Next, the wool goes through a process called carding. (No, this doesn’t mean asking the wool for it’s ID to check if it’s over 21.) Carding involves untangling the wool by passing it through cylinders to form a standardized web. If you have a fluffy dog, it’s kind of like what happens if you use one of those needle-type dog brushes.
5. The carded wool is combined to create batts that are rolled in preparation for felting.
6. Layers of batts are combined using steam on a conveyor belt.
7. The combined layers of batts then go through a process called “hardening,” which uses a drop-down plate that applies force to the batts, further matting the fibers.
8. Fulling is next, where the fibers are fed through a set of upper and lower steel rollers which are covered with rubber or hard plastic to enable the batts to move about. This process shrinks the batts and also hardens them.
9. The felt is then cleaned to remove impurities and any chemicals used in the process.
10. The felt is then dyed.
11. Then the felt is laid out to dry. The felt fabric that isn't dyed goes directly from washing to drying.
12. Then the felt goes through a “pressing” process to even out the felt and ensures consistent thickness in the fabric. In some cases, the pressing process is used to further interlock the fibers.
13. Finally, the felt is shaved to remove uneven edges and unlocked fibers from the fabric.

For combined felt, the natural and synthetic fibers go into big open cylinders that have steel nails inside to help with combining the different fibers.

Afterward, they are carded and the rest of the process is similar to what we outlined for wool felting.

Types of felt fabric

As we mentioned, there are three main types of felt: natural, synthetic, and combined.

• Natural fiber. Made from 100% natural fibers such as wool, furs, or cotton.
• Synthetic fiber. Made from synthetic fibers such as acrylic, rayon, polyester, and nylon.
• Combined fibers. Made from a combination of natural and synthetic fibers, most commonly a mix of wool and acrylic.

But! There’s also different types within that too. Let’s dive into a few of those here.

Crafting acrylic felt

Alright, this is probably the type of felt you know the best. The felt you’d find in a kid’s project or what you’d find at Michael’s.

These are synthetic felt fibers that use interlocking acrylic. Why is this the OG crafting felt? A few reasons.

First, they’re stiffer than natural fiber felt, yet easier to cut. Two, they’re cheaper than other types of felt. And three, they can take on different pigments really well so you can dye them all different types of fun colors.

Eco-friendly felts

Made from recycled plastics, these are similar to acrylic felts (made by interlocking plastics), but more eco-friendly (surprise surprise). This type of felt also makes excellent craft material because it's stiff, coarse, and waterproof.

Eco-friendly felts can be made from recycled felt, yarn fibers, or leftover carpet fibers. Considering the “eco-friendly” in the name, it makes sense that this felt doesn’t use any chemicals, glues, or adhesives so they’re non-toxic — great for kiddos.

The Eco-Plush rug pad is one such example of this. (So I mean, we’re not biased or anything, but it’s basically the best kind of felt fabric. 😉)

Blended wool felt

This material is made from mixing wool with synthetic fibers, such as acrylic. The two most common ratios that exist for this combination are:

• 35% wool; 65% acrylic
• 20% wool; 80% acrylic

These are good for crafts, but you’ll also see this felt in accessories like pillows or plush toys because they have a firm yet soft texture.

100% wool and natural fiber felt

100% wool felt is made by interlocking wool fibers together to create a fabric that doesn’t wear down easily. (That whole process we explained earlier.)

Under a microscope, the surface of wool appears to have scales. The felting process interlocks these scales, creating a durable, water-resistant material. This would be the type of felt that people used way back when for clothing, especially in rainy climates like England and Scotland (think kilts).

It’s non-flammable, too — wool singes and the flames simply go out. This makes it ideal for lining fire-fighter uniforms because while it’s non-flammable, it’s also lightweight so it doesn’t slow the firefighters down or impede their movement.

Properties of felt fabric

Felt, unlike most other fabrics, is not woven or knit, meaning it doesn’t have warp and weft threads (the vertical and horizontal threads in weaving). This means that it doesn’t easily fray at the edges, and also makes it easy to cut and work with (since cutting it will not destroy the integrity of the entire fabric).

Felt is also durable because many layers are interlocked in its construction. It’s water-resistant and non-toxic.

Advantages of felt fabric

What’s so good about felt? Everything.

Okay not everything, but felt does have a lot of benefits. Specifically, it’s durable, warm, lightweight, protective, insulating, and soundproofing. Let’s dig into those a bit more.

Durable

Due to the interlocking process used in manufacturing, felt is strong and durable. Seriously, felt can take a beating and be just fine.

In terms of rug pads, this makes your pads durable and long-lasting.

Warm but lightweight

The fibers in felt are lightweight, but you’ve got a TON of them all interlocked together so they’re also warm. Interlocking creates the lightweight quality of the fabric, as it’s compressed through pressure being applied when matting the fibers.

Keep in mind, because of the density, felt isn’t going to be your ultra-lightweight performance clothing. But unless you’re clocking crazy miles, you probably wouldn’t notice the weight so for the amount of warmth it provides it’s pretty damn good.

Plus, when used in rug pads, that weight and density can actually be nice — it can help keep the pad flat and adds more cushion to your rug. However, since the pad is still fairly low profile (the whole density thing) the felt is unlikely to raise your area rug too high up, so the rugs aren’t a tripping hazard.

Protective

Felt is used for lining clothing such as boots and coats for the winter season because it’s warm, lightweight, and water-resistant. That doesn’t mean waterproof, it’s just that wool fibers naturally have some water resistance, especially when tightly woven together like with felt (have you seen where sheep live?? They need some water resistance).

Because it’s water-resistant, felt is also good for rug pads. Any liquid will take a moment before starting to soak in. And even then the recycled felt we use is pretty great at absorbing liquid too. This gives you time to clean any spills before they can damage your floors.

Plus, since the felt is only water-resistant and not non-porous waterproof, it means the material is also breathable. What’s the benefit to that? It means you’ll have airflow between the rug and floor. So, even if liquid were to get under the pad, it wouldn’t get trapped there—it could simply evaporate up through the pad.

Insulating and soundproofing

Because many layers of felt layers are interlocked together during felting, the resulting fabric is excellent for insulation and soundproofing. They have premium cushioning and are able to absorb sound.

What is this quality good for? You guessed it—rug pads.

Especially in a multi-storied house or apartment complex, the extra soundproofing can be a massive benefit to keep the peace between neighbors.

(P.S. The Eco-Plush rug pads we carry have excellent soundproofing. 😉)

Disadvantages of felt fabric

Nothing’s perfect and felt certainly isn’t an exception here. We want to make sure you really know felt — the good, and the bad.

Moths (For Wool Felt)

Even though felt is a strong, durable material, it can be destroyed by moths. The whole natural thing? Moths are a big fan of that too, unfortunately. Specific species of moths actually feed on animal fibers like wool, so your wool clothing is an all-you-can eat buffet to them.

(Note: our rug pads use recycled synthetic felt, so you shouldn’t have to worry about the whole moth issue if you’re thinking of getting a felt rug pad.)

Not grippy

Felt is not a grippy fabric. This is great for socks when you want to go sliding around on wood floors.

(source)

Not so great when your small area rugs go slipping out from under you (or under your dog). For this reason, some manufacturers use adhesives to ensure that rug pads stick to the floor (which in itself can be damaging to the floor).

Instead, we design our non slip rug pads to grip the floor by adding rubber backing.

The Contour-Lock and Superior-Lock rug pads both use felt with a natural rubber backing.

Coarse texture

The manufacturing process of felt can often make the surface a bit coarse and rough, so it can be a bit scratchy on the skin (especially synthetic felt). It’s still a soft enough surface that it won’t scratch floors or even be that uncomfortable on the skin, it’s just not going to compare to something like fleece or alpaca wool when it comes to softness.

FAQs about felt fabric

Still have questions? We’ve got you covered. Check out these other commonly asked questions about felt that we’ve answered here for you.

Is melton the same as felt?

Melton is similar to felt and is often mistaken for it.

Melton is a woven fabric, but the finishing of melton makes it shrink and appear matted like felt.

Where can you buy felt fabric?

Felt can be bought by the yard or in pre-cut felt sheets. Michael’s or similar crafting stores are good places to buy felt. Most crafting or fabric store should carry some felt.

(Though keep in mind, this is just felt, not made for anything specific — if you want something specific for say, rug pads, we’ve got you covered with our 100% felt rug pad.)

Can you wash felt fabric?

Yes, felt can be washed. We recommend washing it by hand using cold water to avoid shrinking though.

Is felt fabric waterproof?

Felt fabric is water-resistant — not fully waterproof. Think of it like a thick fuzzy jacket in the rain that isn’t necessarily a rain jacket; it’ll keep you dry for a while, but eventually you’ll get wet.

Is felt a non-woven fabric?

Yes, it’s a non-woven fabric made from interlocking fibers.

Is felt a strong material?

Yes, it’s a strong material. However, it’s not like steel metal-level strong — it’s still a fabric and if you push it too hard, those interlocking fibers can come apart.

What is the best quality felt?

100% wool felt has the best quality for water resistance, comfort, and durability — but it can also get eaten by moths.

Are felt and fleece the same?

No, they’re not the same. Felt is made from natural wool or synthetic fibers and is non-woven. Fleece, on the other hand, is woven and made entirely from plastic.

Can you tumble dry felt?

No, it is better to air dry it as putting it in dryers can misshape it and mess with the interlocking fibers.

Can you iron felt?

Yes, it's fine to iron felt. No need to use steam for it either.

How do I clean dusty felt?

Dusty felt can be cleaned using a clothes brush to remove dust and lint. If it’s on your floor like a rug pad, you can also use a vacuum cleaner on a low setting.

Does felt stick to felt?

Natural fiber felt does not naturally stick to felt unless glue or adhesive is applied. However, you will see those acrylic felt boards that do stick together — that’s because the fibers interlock with each other like a weaker version of velcro.

Does felt unravel?

No, felt does not unravel — it’s non-woven, so there’s really nothing to unravel.

Is felt a good insulator?

Yes, felt makes a good insulator because it’s matted and dense with all the fibers pushed together.

What is flic flac felt?

Flic Flac felt is a felt fabric that is ideal for art and crafts use. It is packaged in assorted colors and already cut into manageable craft squares.

How can you tell if felt is wool or acrylic?

Wool felt is more supple and softer to touch than acrylic felt. Acrylic felt is stiff and coarse.

Is felt a sustainable material?

It depends on the type. Wool felt is generally a sustainable material because it’s renewable and biodegradable. It doesn't cause unnecessary environmental pollution and it’s economically sustainable.

Recycled fiber felt is also fairly sustainable since it uses recycled materials and can be re-recycled. On the other hand, brand new acrylic fiber felt can push the envelope on the whole sustainable thing since it uses polyesters and plastics. It can still be recycled and doesn’t have to use harsh or toxic chemicals, so it’s certainly not the worst.

Other materials used for rug pads

If you’ve realized that felt doesn’t suit your fancy when it comes to rug pads, that’s totally fine! We have other rug pad materials too.

The Anchor Grip uses felt and EVA while the Eco Plush rug pads use 100% felt. The RugPro, Contour-Lock, and Superior-Lock pads use a combination of felt and rubber.

EVA (ethylene-vinyl acetate)

The Anchor Grip pad is a felt and EVA rug pad made in the United States. It has great grip and doesn’t stick to your floors, discolor them, or dry them — making it an ideal rug pad material for vinyl and luxury vinyl plank flooring.

Natural Rubber

Natural rubber is a naturally occurring polymer that comes from the rubber tree.

It’s an ideal material to use in rug pads because it grips floors, ensuring your rugs stay in place, without damaging the floor or your rug. Plus, it’s non-toxic and doesn’t have a strong smell.

We use natural rubber in our non-slip rug pads, such as Nature’s Grip and Super-Lock Natural, for its gripping properties.

For more Felt Flooringinformation, please contact us. We will provide professional answers.