Flooring Underlayment 101: All You Need to Know

By Samuel N •  Updated: 09/27/22 • 

When installing new flooring, choosing the right underlayment is very crucial. If you’re new to the flooring world, you may not know what underlayment is. What is flooring underlayment, and why is it important?

Flooring underlayment comes in different materials. The material you choose to use for underlayment will depend on the type of flooring material you’ll install. If the flooring you’re installing comes with an attached underlayment, you will not need to install a separate underlayment.

The Purpose of Underlayment

The major purpose of underlayment is to provide a flat and smooth surface and allow the flooring to shrink and expand. However, underlayment also has additional benefits. Here are some of the reasons to install flooring underlayment.

Types of Flooring Underlayment

Foam Underlayment

This is one of the basic types of underlayment you’ll get around. It is cheap and very versatile. Foam underlayment can be used under various flooring types, including laminate, wood, and vinyl. Foam underlayment offers a good amount of sound reduction and cushioning. It is very easy to install, and some foam underlayments come with adhesive strips for easier installation.

Rubber Underlayment

Rubber is a super versatile flooring underlayment, best for absorbing and insulating sound. If you have hollow-sounding floors, rubber underlayment will do wonders. Besides blocking sound, rubber underlayment protects your floors from mold and mildew. Rubber underlay can be used under wood, carpet, or tile flooring. For vinyl flooring, rubber underlayment cannot be used because of staining.

Cork Underlayment

Cork is a renewable and eco-friendly underlayment option. Cork is antimicrobial in nature, preventing mold, mildew, and bacteria growth. This makes cork underlayment great for allergy sufferers. Cork, like rubber, is good at absorbing sound. It also adds insulation to your home, thus reducing your heating bills. Cork underlayment is suitable for most flooring types. However, it should not be installed in basements, bathrooms, or other flood-prone areas due to deterioration. In flood-ridden areas, use rubber underlay or a cork underlay with a moisture barrier.

Felt Underlayment

Felt underlayment is usually denser than foam underlayment and is made from recycled fibers. The density of felt underlayment makes it an excellent sound absorber and insulator. Felt underlayment is also suitable for giving your flooring a cushioning step. For extra durability, a moisture barrier is added to the felt underlayment. Felt can be used in different types of flooring, including hardwood, vinyl, laminate, and more, without a problem.

Installing Underlayment

Installing Underlayment

Installing Underlayment

Installing underlayment is usually very easy. Here is a step-by-step guide on how to install flooring underlayment.

  1. Clean Subfloor – The subfloor must be cleaned before installing underlayment on your floor. You should eliminate all dirt and loose debris using a broom or vacuum cleaner. You should also remove any existing installations that might get in the way of installing underlayment. This includes baseboards or door frames if the room has any.
  2. Repair and Level Subfloor – After removing dirt and debris, you should inspect your subfloor carefully to ensure it’s flat, dry, and in good condition. If you notice issues with your subfloor, you should fix them before moving forward. Fill excess gaps, fix uneven subfloors, and nail down nails that are sticking out. Once done, sweep dirt and debris left on the subfloor.
  3. Installing Underlayment – Most underlayments come in rolls. You should start by rolling out underlayment one row at a time. You should install the underlayment perpendicular to the direction you will lay out the flooring. When installing underlayment, do not overlap the rows. Secure them by taping between the seams to keep the underlayment in place.

That is it. Once done, you’re ready to go and start installing your preferred flooring.

What Happens if You Don’t Use Underlayment?

If you cut corners and avoid underlayment, you will experience performance and quality issues.

For floorings that rely on tongue-and-groove technology, such as laminate, imperfections on the subfloor can lead to excess wear. Over time, foot traffic and furniture movement will create a weak point in your floor system.

Moisture and other water problems affect your new floors’ longevity. How effectively you keep your flooring dry matters a lot. When moisture is introduced, subfloors can wreak havoc on many types of flooring, including hardwood and laminate. Some underlayments can also act as moisture barriers, protecting by stopping moisture from rising.

If you do not like walking on a cold floor, skipping the use of an underlayment might make things worse. Concrete subfloors, for example, become very damp and cold during colder months. They’ll suck warmth and leave your floors ice cold. The lack of underlayment between the subfloor and your flooring is to blame.

If you hear hollow noises, footsteps, and other sounds from your floor, they could be because they lack underlayment. Underlayment dampens and prevents floor noise from traveling. If your floors lack underlayment, these sounds and noise will be accentuated, impacting your work and home life.

When to Skip Using Underlayment

There are some situations where you can avoid using underlayment.

On floors where moisture is present and using underlayment will stop airflow or inhibit drainage options, it is better to skip using underlayment. Your previous floor covering can also serve as underlayment. For example, laminate flooring is usually laid directly over vinyl sheets without a problem.

Some floorings also come with a layer of underlayment attached. This layer provides the same properties as an underlayment; thus, installing an underlayment is not necessary.

Samuel N

Samuel N is the founder of Improve Floor and has been in the flooring industry since 2005. Since then, his mission has been to make flooring easier for everyone. He helps countless people with flooring installation, finishing, maintenance, and repairs each year.