What Is Flooring Underlay? (6 Questions Answered!)

Choosing new flooring can feel overwhelming, right?

There are so many options – hardwood, laminate, tile, carpet…

And just when you think you’ve made a decision, someone asks:

“What about the underlay?”

Suddenly, you’re back to square one!

As a flooring contractor for over 15 years, I’ve seen firsthand how often underlay is overlooked.

But trust me, it’s a critical part of any flooring system.

It impacts everything from comfort to longevity.

In this article, I’m going to answer six key questions about flooring underlay.

My goal is to demystify this important topic and help you make the best choice for your home.

Let’s dive in!

Section 1: What is Flooring Underlay?

Okay, let’s start with the basics.

What exactly is flooring underlay?

Simply put, it’s a layer of material installed between the subfloor (the structural floor beneath) and the finished flooring.

Think of it as a cushion or a foundation for your new floor.

Its primary purpose is to provide a smooth, stable, and supportive surface.

There are many different types of underlay available.

These depend on the type of flooring you’re installing, the subfloor conditions, and your specific needs.

Some common materials include:

• Foam (polyethylene, polyurethane)
• Rubber (recycled, crumb rubber)
• Felt (synthetic, natural)
• Cork

But what does it do?

Flooring underlay acts as:

• A Barrier: It protects the flooring from moisture and irregularities in the subfloor.
• A Cushion: It adds comfort underfoot and reduces noise transmission.
• A Moisture Control Element: Certain types can prevent moisture from damaging the flooring.

Think of it like this: your subfloor is the foundation of your house, and the underlay is the foundation for your floor.

It’s that important!

Section 2: Why is Flooring Underlay Important?

So, why bother with underlay at all?

Can’t you just install the flooring directly on the subfloor?

Technically, yes, you can.

But I wouldn’t recommend it!

Underlay offers a ton of benefits that significantly improve the performance and lifespan of your flooring.

Let’s break it down:

• Longevity and Performance: Underlay protects your flooring from wear and tear, extending its life. It also helps prevent issues like squeaking, cracking, and warping.

• Sound Insulation: This is a big one! Underlay can significantly reduce noise transmission between floors. If you live in an apartment or have kids, you’ll appreciate this. Some underlayments have an Impact Insulation Class (IIC) rating of 70 or higher, meaning they block a significant amount of sound.

• Thermal Insulation: Certain types of underlay can provide additional insulation, helping to keep your home warmer in the winter and cooler in the summer. This can lead to energy savings!

• Leveling Uneven Floors: Let’s face it, most subfloors aren’t perfectly level. Underlay can help to smooth out minor imperfections, providing a more even surface for your flooring.

• Comfort Underfoot: This is often overlooked, but underlay makes a huge difference in how your floor feels. It adds a layer of cushion, making it more comfortable to walk on.

I’ve seen firsthand how underlay can transform a flooring project.

I once worked on a condo where the client was constantly complaining about noise from the apartment above.

After installing a sound-dampening underlay, the complaints stopped!

It made a huge difference in their quality of life.

Section 3: What Are the Different Types of Flooring Underlay?

Now, let’s talk about the different types of underlay materials.

Choosing the right one can be tricky, but it’s crucial for optimal performance.

Here’s a rundown of some common options:

• Foam Underlay: This is a popular and affordable choice, especially for laminate and engineered wood flooring. It provides good cushioning and sound insulation. However, it’s not ideal for areas with high moisture.

• Rubber Underlay: Rubber underlay is known for its excellent sound absorption and durability. It’s a great option for apartments, condos, and commercial spaces. Recycled rubber underlay is also an environmentally friendly choice.

• Felt Underlay: Felt underlay provides a dense, supportive layer for carpet and hardwood flooring. It offers good insulation and can help to extend the life of your carpet.

• Cork Underlay: Cork is a natural, sustainable material that offers excellent sound and thermal insulation. It’s also naturally resistant to mold and mildew. It’s a great choice for those with allergies.

Here’s a quick table summarizing the pros and cons of each type:

When choosing an underlay, consider the specific requirements of your flooring type.

For example, carpet typically requires a thicker, denser underlay than laminate.

Also, think about the subfloor.

If it’s prone to moisture, you’ll need an underlay with a built-in moisture barrier.

Section 4: How to Choose the Right Flooring Underlay?

Alright, so you know what underlay is and why it’s important.

But how do you actually choose the right one for your project?

Here are some key factors to consider:

• Type of Flooring: As I mentioned before, different flooring types have different requirements. Check the manufacturer’s recommendations for the best underlay.

• Subfloor Condition: Is your subfloor level, dry, and free of debris? If not, you may need to address these issues before installing the underlay. For uneven subfloors, consider a thicker underlay or a self-leveling compound.

• Intended Use of the Space: Is it a high-traffic area? Do you need extra sound insulation? These factors will influence your choice.

• Moisture Levels: If you’re installing flooring in a basement or other moisture-prone area, you’ll need an underlay with a built-in moisture barrier.

• Budget: Underlay prices can vary widely. Set a budget and stick to it, but don’t skimp on quality. A good underlay is an investment that will pay off in the long run.

Before you buy, measure the area where you’ll be installing the flooring.

This will help you determine how much underlay you need.

When measuring, add a little extra (around 10%) to account for waste and overlaps.

Also, check your local building codes.

Some areas have specific requirements for flooring underlay, especially in multi-family dwellings.

For example, many condos require a certain IIC rating for sound insulation.

Section 5: How Does Flooring Underlay Affect Installation?

Okay, let’s talk installation.

Underlay can significantly affect the installation process, so it’s important to get it right.

Here are a few things to keep in mind:

• Preparation is Key: Make sure your subfloor is clean, dry, and level before installing the underlay. Remove any debris, nails, or screws that could interfere with the installation.

• Follow the Manufacturer’s Instructions: Each type of underlay has its own specific installation instructions. Read them carefully and follow them to the letter.

• Proper Seams: When installing underlay, make sure the seams are tight and secure. Use seam tape to prevent moisture from seeping through.

• Avoid Overlapping: Overlapping underlay can create uneven spots and compromise the performance of your flooring.

• Secure the Underlay: Depending on the type of underlay, you may need to staple, glue, or tape it to the subfloor. This will prevent it from shifting and bunching up over time.

I’ve seen some pretty disastrous underlay installations over the years.

One common mistake is not properly preparing the subfloor.

If you install underlay over a dirty or uneven subfloor, you’re just asking for trouble.

Another mistake is using the wrong type of underlay for the flooring.

I once saw someone install a thin foam underlay under a heavy hardwood floor.

The underlay quickly compressed, and the floor started to squeak and buckle.

It was a costly mistake that could have been avoided with a little research.

Section 6: What Are Common Myths and Misconceptions About Flooring Underlay?

Finally, let’s bust some common myths and misconceptions about flooring underlay.

• Myth #1: Underlay is Unnecessary: As I’ve emphasized throughout this article, underlay is not an optional accessory. It’s an essential component of a well-performing flooring system.

• Myth #2: Underlay is Only for Specific Flooring Types: While some flooring types benefit more from underlay than others, it can improve the performance of virtually any type of flooring.

• Myth #3: All Underlay is the Same: As you’ve learned, there are many different types of underlay, each with its own unique properties and benefits.

• Myth #4: Underlay is Too Expensive: While it’s true that some underlay can be pricey, it’s an investment that will save you money in the long run by extending the life of your flooring and reducing the need for repairs.

• Myth #5: I Can Install Underlay Myself: While some DIYers can handle underlay installation, it’s often best left to the professionals. A poorly installed underlay can cause a host of problems.

I often get asked questions like:

• “Do I really need underlay under my carpet?” (Yes!)
• “Can I use the same underlay for laminate and tile?” (No, they have different requirements.)
• “How thick should my underlay be?” (It depends on the flooring type and subfloor condition.)

Don’t be afraid to ask questions and do your research before making a decision.

Conclusion: Summarizing the Importance of Flooring Underlay

So, there you have it!

Everything you need to know about flooring underlay.

As I’ve shown you, underlay is not just an optional extra.

It’s a crucial component that can significantly enhance the overall flooring experience.

By choosing the right underlay for your specific needs, you can:

• Extend the life of your flooring
• Improve sound and thermal insulation
• Create a more comfortable surface underfoot
• Protect your flooring from moisture and damage

Don’t make the mistake of overlooking this important aspect of your flooring project.

Consider your flooring choices holistically.

Recognize the critical role that underlay plays in achieving your home improvement goals.

And if you’re still unsure, don’t hesitate to consult with a flooring professional.

We’re here to help you make the best choices for your home!

Learn more