Underlay for Wood Flooring: Here’s What You’ll Need

Not only do you need to take the time to find the best wood flooring for your home, but you also need to choose the best underlayment. The underlayment is there to protect your subfloor and ensure that you get the most out of your wood flooring, as it ensures the plank’s longevity. 

When choosing an underlayment, you need to consider several different factors, including the type of subfloor you have, the wood flooring you’ve chosen, and several other things. Wondering how to choose the best underlay for your home? We’re about to clear up the mystery right here!

What Does an Underlay Do?

An underlay does more than just sit between your subfloor and wood flooring. It serves several important purposes, making it all the more crucial to choose the best underlayment for your home. 

Here are some of the many things that an underlay does:

Provides Shock Absorption and Moisture Protection

Have you ever wondered what it would be like if your hardwood floors were laid directly over your subfloor, without any protection in between? Not only would the floors be subject to any moisture seeping up from the foundation of your home that goes through the subfloor (especially in homes without basements), but the probability of your hardwood planks getting damaged by the moisture would go up.

In addition, without this protective layer, the hardwood flooring is directly against the subfloor, making both subject to warping and cracking as they press up against one another. As a result, the lifespan of your subfloor and hardwood floors would be exponentially shorter than they should be.

Makes Your Home a Bit Quieter

Hardwood floors are seldom quiet. You can hear everything, from cats running up and down the hall to the footsteps of people on the floor above you. 

However, with a good underlayment, your home will be slightly quieter. The underlay takes away some of the noise due to its sound dampening qualities. You’ll be thankful that you can no longer hear every single footstep.

Reduces Your Energy Bills

Energy bills are ridiculously high these days, and they’re even more so without a good underlayment. That protective layer located in between your flooring and subflooring provides some insulation. It keeps the cold air in place during the summer and the warm air from escaping through the floor in the winter. 

As a result, your heating and cooling bills will go down as long as the right kind of underlay is properly installed.

Levels Out Your Subfloor

In order for your hardwood floor to last as long as possible, it needs to be installed over a level subfloor. This is easier said than done when the subfloor is already imperfect, with spots that are lower or higher than others. 

Rather than completely replace the subfloor, which can add to the cost of the installation, you can use the underlayment to level things out. By taking the time to ensure that the underlayment covers and repairs those imperfections, your new hardwood flooring will sit properly on top, and you won’t have to worry about any additional expenses.

Types of Underlayment

Now that you know how important it is to have an underlay installed between your subfloor and your hardwood floor, it’s time to discuss the many available options. In general, you’ll see that there are five main types of underlay. Let’s go over them in some detail.


Foam is the most common type of underlay. It comes in various styles and thicknesses, making it easy to find the right kind for your floor. Plus, foam contains all of the benefits of an underlay, including moisture reduction, insulation, and sound dampening. It’s also affordable, making it one of the best options out there.

Spreadable Moisture Layers

You’ll only need a spreadable moisture layer in a very specific situation. If you want to glue down your hardwood flooring planks onto a plywood or hardwood subfloor, then you’ll need to use this type of underlayment. 

Once you spread it on with a trowel and allow it to dry, it will provide just the right type of protective layer that also helps the glue adhere.


Although a cork underlay can be pricey, it works just as well as foam. It’s great for absorbing sound and providing a bit of cushioning under the feet. In addition, cork has plenty of natural antimicrobial properties, so it prevents mold and mildew from growing in between your flooring and subfloor. 

Cork is also a good insulating material. If you have a hardwood subfloor, a cork underlay may be just what you need to protect both it and your new wood floor.

Vapor Barriers

A vapor barrier is exactly what it sounds like: a thin, plastic layer that works to keep moisture from seeping between the subfloor and hardwood floor. These barriers are usually sold in rolls and can easily be cut down to size. 

You’ll find several different types on the market, from those designed for tile (not an issue here), laminate, and even hardwood flooring. Since vapor barriers are so thin, they are easily combined with other types of underlay.


Speaking of combinations, this particular type of underlay consists of both foam and a vapor barrier all in one. It often has the vapor barrier attached on one side of the foam, making it clear which side needs to be placed down facing the subfloor. 

If you want a solid underlay that does many things, from reducing moisture and preventing mold to dampening sound and providing insulation, you want a combination underlay.

The Role of Your Subfloor

Your underlay needs to be compatible with your subfloor. Since there are three main types of subflooring—concrete, plywood, and hardwood—you need to know which of the many varieties of underlayment will work best with them. Otherwise, you could end up with quite a problem on your hands.


If you have a concrete subfloor, you’ll need an underlay that prevents moisture from seeping up underneath. A vapor barrier will work well, especially when paired with a lightweight and thin form underlay. In addition, depending on your location (some parts of the country are much more humid than others), you may need to use a spreadable moisture layer.

Plywood and Hardwood

With plywood and hardwood subfloors, you have many more options to choose from. For example, you can go with foam, cork, or combination underlayments, or even a vapor barrier. In addition, you can use a spreadable moisture barrier if you plan on gluing your wood flooring to your plywood subfloor.

Considering Your Flooring

With many types of wood flooring available, from engineered wood and laminate to traditional hardwood from Hardwood Bargains, this is yet another factor to weigh in your decision to pick the best underlayment. Some types of flooring work best with particular underlayments while can be flexible.

For example, suppose you are planning on installing engineered wood or laminate flooring that snaps together and floats over the subfloor. In that case, you’ll need an underlay like foam or combination as it will allow that flooring to stay firmly in place and provide some protection.

On the other hand, if you want to install a hardwood floor with nails, you’ll need an underlay that can support it. A cork underlay works well in this particular example. If you want to glue that flooring down instead of using nails, then choose a spreadable moisture layer.

Final Thoughts

Picking a type of underlayment requires you to consider many different factors, from the type of subfloor that you already have to the flooring that you want to install. In addition, you need to think about the overall height of the underlay, as you don’t want one that will raise the final flooring too much, causing tripping hazards when moving from room to room. 

With so much to think about, it makes sense to spend some time choosing the very best underlayment for your home. 


Choosing the Right Underlay for Your Laminate Flooring Project | DIYist

How to Use Foam Underlayment Under a Hardwood Floor | SF Gate

The 7 Best Flooring Underlayments | The Spruce

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