Does A Hardwood Floor Need Underlayment Or Subfloor?

Solid hardwood flooring is both a major upgrade and investment to your home that can last you a lifetime. Have you decided to take the plunge and splurge on that hardwood you've always wanted? Wondering if a subfloor or underlayment is needed as with laminate flooring? We've researched all about hardwood installation and will share our findings below.

Subflooring is absolutely necessary when installing hardwood flooring. With underlayment, there are very few instances where using an underlayment is not necessary or required when installing hardwood flooring. The only instance we found that underlayment is not required is if you have an already existing plywood subfloor that is smooth and level. In this case, you can safely forgo the underlayment.

What purpose does underlayment provide? What happens if you don't lay the underlayment? Continue reading for answers to these questions and more regarding the use of underlayment for hardwood flooring.

Does A Hardwood Floor Need Underlayment Or Subfloor?

What exactly is underlayment?

When installing hardwood flooring, it will rest on the subfloor. Subfloor is typically cement, plywood, or some other wood, possibly particle board or OSB (oriented strand board). Underlayment is the thin material that rests between the subflooring and the hardwood. If you're using engineered hardwood flooring, the underlayment allows the flooring to float. It serves four main purposes:

  • Stability
  • Support and insulation
  • Noise reduction
  • Moisture barrier

Even in the instance where you can safely forgo the underlayment, you may have to have an underlayment for warranty purposes. It's always a good idea to check with your manufacturer prior to any installation.

In the case of condos or apartment building renovations, the underlayment may be a requirement to meet certain building codes. If you do not use underlayment, you may risk not passing building inspections. You can call your local building and zoning office to check if it's a requirement.

Installing underlayment is fairly straightforward and simple. It is not a hassle and you can accomplish it easily by yourself. If you like visuals, check out this tutorial:


The underlayment can address minor flaws or dips, creating the level surface needed for installing hardwood flooring, adding to greater stability for the hardwood. 

With the installation of engineered hardwood flooring, they rely on the underlayment to allow the flooring to float. Floating floors are not nailed, glued, or otherwise attached to the subflooring. They can expand and contract when indoor temperatures vary or are exposed to moisture in the indoor air. The underlayment makes the floating floor stable and prevents much of the movement experienced from expanding and contracting.

Support and Insulation

Adding an underlayment provides stability and support for the flooring, especially during varying temperature changes when the wood can expand and contract.

Hardwood can be a cold surface to walk on, as it absorbs the varying temperature changes from the subfloor it sits on. Underlayment insulates the flooring from the subfloor. Some underlayment is specifically designed to work with radiant heat flooring systems.

Noise Reduction

Many homeowners report one negative aspect involved in having hardwood flooring: it can be quite noisy. Underlayment has the ability to reduce noise levels and vibrations caused by footfalls. If you live in a multi-level home, this is an even bigger benefit as the underlayment acts as a sound barrier between multi-levels in these homes.

Moisture Barrier

Not all underlayments are fitted with a moisture barrier. So, you will need to make sure the underlayment you select has this feature. This is probably one of, if not the biggest, benefits of underlayment. If your wood is exposed to moisture seeping up from the subfloor, it can warp, crack, rot, weaken, or grow mold. You can avoid these issues if a proper moisture barrier underlayment is used under the wood flooring.

What happens if you don't use underlayment?

A damage flooring due to moist or water leakage on the flooring

The biggest repercussions you'll face if you don't use underlayment is moisture coming up from the subfloor and damaging your flooring. This can cause the flooring to warp, rot, crack, weaken, or grow mold and mildew.

To make matters worse, if you don't add an underlayment prior to installation, you might risk voiding the warranty. Check with the manufacturer of the flooring you've just invested in. Most manufacturers will void the warranty if the product is installed without the proper moisture barrier underlayment.

What is the recommended underlayment for hardwood flooring?

Different colors of cork underlayment collection at a shop

The type of underlayment you use will likely depend most upon if you're installing on wood subflooring or concrete subflooring. There are four commonly used underlayments for hardwood flooring.


Foam is the most basic, easiest to install, and most cost-effective underlayment for wood flooring. The most notable benefits of foam underlayment are noise-reduction and cushioning. There are many varying styles and thicknesses available on the market.

Check out this foam underlayment on Amazon.


Rubber is a great mold and mildew protectant. It is a great choice to use over wood and cement subflooring. It also boasts great noise-reduction qualities.


Cork is an eco-friendly underlayment product with excellent noise dampening and insulation qualities. However, a warning about cork: it does not contain a moisture barrier and moisture can damage it easily, along with your flooring. Due to this, if you need that moisture barrier, investing in rubber cork would be your best option. It is usually made by mixing cork with recycled rubber and provides that moisture barrier.

Check out this cork underlayment on Amazon.


Felt is probably the most commonly used underlayment. It is affordable, has a moisture barrier, provides sound muffling, and is denser than foam. It's also typically produced from recycled materials, making it a top choice for eco-friendly homeowners.

Check out this felt underlayment on Amazon.

Can you use roofing felt under hardwood flooring?

A roof installer putting installing roof shingle underlayment

Asphalt roofing felt can and has been used successfully as an underlayment for hardwood flooring. A bit of caution though: if you're using a floor radiant heating system, you will want to avoid roofing felt as it will produce a smell from the asphalt mixed into the felt when it's heated.

Do you need a moisture barrier under hardwood flooring?

Selecting an underlayment with a moisture barrier is a must. As mentioned above, there are many manufacturers that will void their warranty if an underlayment without a moisture barrier is used.

What kind of subfloor do you need for hardwood?

Prep the subflooring prior to installation. Patch and address all major dips and flaws prior to installation. The subfloor will need to be dry, level, and structurally sound. Most experts recommend installing hardwood flooring on a plywood subfloor, ranging from 1/2 to 3/4- inch in thickness and rated A/C. In addition, you can use particle board, OSB, and concrete for subflooring with hardwood as well.

In Summary

Hardwood is a home investment that should easily last a lifetime with proper care. Installing the proper underlayment is a simple and easy step. It not only protects your investment but also enhances it with other added great benefits too. Now you can confidently pick out which underlayment will work best for your individual home scenario.

If you enjoyed this article, please consider these for further reading:

How To Wax Hardwood Floors [Including Natural Methods]

17 Stunning Hardwood Floor And Wall Color Combinations

What Type Of Rugs For Hardwood Floors? [5 Great Options]

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