When it comes to installing hardwood flooring, one of the most important decisions you will make is what type of underlayment to use. Underlayment serves three main purposes: sound insulation, moisture control and insulation. There are many different types of underlayment available on the market today, made from a variety of materials, making it difficult to decide which is best for your project.

In this guide, we will discuss the different types of underlayment available and their benefits, so you can make an informed decision on which is the best underlayment for your hardwood flooring installation.

What Are Underlayments?

Underlayment is a layer of material that is installed between the subfloor and the finished flooring. The most common type of underlayment for hardwood floors is a thin, foam sheet. This type of underlayment provides a smooth surface for the hardwood planks to be laid on top and also acts as a barrier between the subfloor and finished flooring.

 

Underlayment also provides some cushioning and noise reduction properties. When hardwood floors are installed over concrete, the thin foam sheet underlayment acts as a barrier to prevent moisture from seeping up through the cracks in the concrete and damaging the hardwood floors.

Why do I Need Underlayment for Hardwood Flooring?

The importance of using the correct type of underlayment cannot be overstated. Choosing the wrong type of material can lead to serious problems down the road, such as buckling and cupping of the hardwood floors.

Types of Underlayment

There are four main types of underlayment: foam, felt, cork and fiberglass. Each has its own unique benefits that make it better suited for certain applications.

Foam

Foam underlayment is the most popular type of underlayment for hardwood floors. Made from a variety of materials including recycled tires and available in different thicknesses, foam underlayment is lightweight and easy to install, making it a popular choice for those who like to DIY.

Besides being relatively inexpensive and widely available, foam underlayment also has excellent sound insulation properties and can help reduce impact noise from footsteps.

The downside of foam underlayment is that it does not provide much moisture protection. If you are installing hardwood floors in a damp basement or on a concrete slab, a different type of underlayment is recommended.

Felt

Felt underlayment is made from recycled fibers and provides good sound insulation and moderate moisture protection. It is also easy to install and relatively inexpensive, making it the second-most popular choice when choosing underlayment.

The downside of felt underlayment is that it can compress over time, which can reduce its sound insulation properties, so it is not best for long-term use. Further, it is not as widely available as foam underlayment.

Cork

Cork underlayment is made from the bark of cork oak trees and is a popular choice for eco-conscious consumers. Cork is a natural insulator and does an excellent job of reducing impact noise. It is also resistant to mold and mildew, making it a good choice for damp basements.

The downside of cork underlayment is that it is more expensive than other types of underlayment and can be difficult to install. It is also not as widely available as foam or felt underlayment. That said, it is durable and can last for many years.

Fiberglass

Fiberglass underlayment is made from recycled glass and is the most durable type of underlayment. It is also mold and mildew resistant, making it a good choice for damp basements. Fiberglass underlayment is also fire resistant, which makes it a good choice for homes in wildfire-prone areas.

The downside of fiberglass underlayment is that it is the most expensive type of underlayment than other types and is best installed by a professional. It is also not as widely available as foam or felt underlayment, but if you are looking for a durable, long-lasting underlayment, fiberglass is the best choice.

Factors to Consider When Choosing Underlayment for Hardwoods

Following is a list of considerations to bear in mind when selecting the best underlayment for your needs:

  • The type of flooring: If you are installing hardwood floors, you will need to use an underlayment that is compatible with nail-down or staple-down installations.
  • The subfloor: The type of subfloor you are installing on will also dictate the type of underlayment you need to use. For example, if you are installing on a concrete slab, you will need an underlayment that is specifically designed for that application.
  • Sound Reduction: If you are worried about impact noise, look for an underlayment with excellent sound-reduction properties such as cork or fiberglass.
  • Insulation: If you are concerned about heat loss, use an underlayment with good insulation properties such as cork or fiberglass.
  • Cushioning: If you want a softer feel underfoot, use an underlayment with good cushioning properties such as foam or fiberglass.
  • Stability: If you are considering the underlayment shifting or bunching up, choose a product with excellent stability, such as fiberglass.

How Thick Should My Underlayment Be?

For hardwood flooring, the minimum thickness of underlayment should be 0.045” (45 mil). However, for best results, it is recommended to use an underlayment that is at least 0.0625” (62.50 mil). 

The thicker the underlayment, the better the sound reduction and insulation properties will be. However, thicker underlayment can be more difficult to install and may add to the overall cost of your project. When in doubt, always err on the side of using a thicker underlayment. 

What is a Moisture Barrier?

A moisture barrier is a layer of material that is installed between the subfloor and the underlayment. The purpose of a moisture barrier is to prevent moisture from seeping up through the subfloor and damaging the hardwood floors.

There are two types of moisture barriers: sheet-type membranes and liquid-applied membranes. 

  1. Sheet-type membranes are made from polyethylene or asphalt-saturated kraft paper and are available in rolls. 
  2. Liquid-applied membranes are made from latex, asphalt or urethane and are applied with a roller or brush.

The type of moisture barrier you need will depend on the subfloor material. For example, if you are installing on a concrete slab, you will need a sheet-type membrane. But if you are installing on plywood, OSB or particle board, you can use either a sheet-type or liquid-applied membrane.

Installing a moisture barrier is important, but it is also important to make sure that the subfloor is dry before you install the hardwood floors. If the subfloor is damp, it can cause the hardwood floors to cup or warp.

You can test the moisture content of the subfloor with a moisture meter. The ideal moisture content for a wood subfloor is between 12% and 15%. If the moisture content is higher than that, you will need to take steps to dry out the subfloor before proceeding with the installation.

Need Some Help with Installation?

Dalton Flooring has been doing business as a carpet and flooring store in Southgate for 40 years. We also have a new location in Rochester Hills, MI. We offer carpet consultations as well as installation from our variety of carpet selections. Whether you visit our store or choose to have samples brought to your home for a Free In-Home Estimate, we have a range of flooring designs and products to help you achieve your desired goals.

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