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Can You Lay Wood Floor Over Carpet Underlay?

The benefits of investing in adequate underlay for your new flooring are endless – from creating a vapor barrier to increasing the soundproof abilities of the floor. However, not all types of underlays are suitable for wood or engineered wood flooring. So, you’ve removed your carpet and found a carpet underlay – can you lay wood floor on top of it?

You cannot lay wood floor over carpet underlay because this underlayment is soft, bendy, and thick. Installing wooden planks over carpet underlay can make your floor bouncy, which damages the locking system. Use a layer of plywood between the carpet and the wood for stability instead.

Confused female carpenter

When using hardwood planks for flooring, you need to know how to preserve the beauty and integrity of the planks. Find out if you should remove or keep your carpet underlay below.

Can You Put Wood Floor Over Carpet Underlay?

When renovating your flooring, the first step is to address the existing floor. Carpet is a popular kind of flooring across the US and Europe because it brings warmth and comfort.

However, carpet installation requires an adequate underlayment that increases the bounciness and soundproofing of the carpet itself. This kind of underlay is usually referred to as “carpet underlay.”

Carpet underlay is specifically designed to improve the look and feel of the material while also protecting expensive fibers from moisture or high traffic damage. While carpet underlay works well for carpet, it isn’t as suitable for wood floors.

It’s not a good idea to install wood floors, including hardwood planks and engineered wood flooring, over carpet underlay!

Consider removing the carpet underlay if:

  • It’s too thick for the hardwood planks, which won’t fit well under doors, baseboards, and cabinets.
  • It’s too bouncy. When walking on your newly installed wooden floor, you might add unnecessary pressure on the locking system (tongue and groove), which can quickly start showing damages.
  • The floor can be much noisier than it’s meant to be because of the empty spaces underneath the planks.

Although these drawbacks should be enough to make you reconsider your choice and substitute the carpet underlay with a more suitable option, some homeowners decide to do it anyway.

Copyright protected content owner: and was initially posted on May 9, 2021.

They might do so as a temporary measure and use less expensive wooden planks, such as laminate or engineered wood.

Carpet Underlay vs. Wood Floor Underlay

If you want to understand why it’s not a good idea, it’s essential to look at the differences between carpet underlay and wood floor underlayment.

There are several different types that you could choose from in both cases, from fibreboards to slotted underlays. However, here are the main differences between the two:

  • Carpet underlay is thicker. Usually 8-10mm (0.31-0.39in) thick – and designed to suck absorbers. When laid underneath the carpet, it prevents it from becoming flat because of the footfall. It can also add another cushioned layer, making the rug bouncy and soft.
  • Wooden floor underlayment is thinner. No more than 1-3mm (0.04-0.12in). It isn’t designed to add a bouncy layer but rather to create a flat surface that can support the installation of planks. While improving the soundproofing and waterproofing characteristics of the floor, this underlay also prevents the planks from becoming deformed or warped.

Carpet and carpet underlayment can also create visible hills and valleys on the surface, which will prevent the locking system of the planks – usually tongue and groove – from being effective. And, in turn, you can expect it to become damaged and less effective in no time.

Should You Put Wood Floor Over Carpet Underlay?

Confused male carpenter scratching head

While putting hardwood floor over carpet underlay is possible, it’s a terrible idea.

Copyright article owner is for this article. This post was first published on May 9, 2021.

However, there are some instances in which you might consider installing your new floor over carpet underlay:

  • If the carpet underlay is thin and relatively flat: One of the main reasons why carpet underlay isn’t suitable for a wooden floor is that it doesn’t provide a flat and reliable subfloor for the planks. However, if your carpet underlay is clean, flat, and thin, you can install temporary flooring.
  • If you’re installing temporary flooring: Temporary flooring such as laminate and engineered wood can be optimal choices if you wish to cover an old carpet in a rental property without taking drastic or irreversible measures. These planks are cheaper than wood and allow you to experiment with the result.
  • If you’ve used a layer of plywood: If you want to benefit from the layer of insulation and warmth that only carpet underlay can provide, you can apply a layer of plywood on top of it to prevent the tongue and groove system from becoming damaged.

Best Types of Underlay for Wood Floor

Wood floor installation

As we’ve seen, the differences between carpet underlay and wood floor underlay can prevent you from installing your new floor directly on the existing underlayment. In some cases, installing hardwood over carpet underlayment can even void the warranty on the wooden planks, which can result in a double loss of money.

Ultimately, before committing to a specific type of floor, it’s crucial to understand the best types of underlayment for it. Here are some of the best ones to consider for hardwood:

  • Vapor barriers: One of the biggest enemies of the hardwood floor is water and moisture. Vapor barriers are thin underlayments that prevent moisture from the concrete subfloor from reaching and damaging the planks.
  • Slotted underlay: Slotted underlay is suitable for engineered wood and hardwood flooring. Using a barrel gun, you’ll apply glue to the underlay’s slots and secure the underlayment to the subfloor. This alternative is convenient to prevent the planks from moving, providing a reliable and secure alternative to other types of underlays.
  • Fibreboard: Fibreboard underlay is the most common type of underlay used for hardwood flooring. Aside from protecting the wood from moisture, this underlay also evens imperfections and undulations on the subfloor, creating an even surface for hardwood application.
  • Stick-backed underlay: This underlay is applied directly to the subfloor and can work for hardwood and engineered wood floors alike. Once installed, the top adhesive layers are gradually removed to secure the planks directly to it.

When substituting your carpet underlay for one of the options seen above, consider consulting an expert to ensure you’re making the right choices – especially if you’re looking to install hardwood floors!

How To Put Wood Floor Over Carpet Underlay

Wood floor planks

As we’ve seen, installing wood floor over carpet underlay isn’t usually the best idea. However, there are some instances where you can pull it off. For example, if the underlay is thin and compact enough, or if you’re installing temporary flooring, it’s a decent option. In these scenarios, check out the instructions below.

And, remember, always ensure that the underlay you pick doesn’t compromise your warranty or planks’ lifespan.

Gather Tape, Plywood, and a Utility Knife

These are the tools that you’ll need:

  • Measuring supplies (tape measurer, ruler, pen)
  • Cutting supplies (utility knife, tile cutter, or table saw)
  • Mallet
  • Floor spacers
  • Plywood

Prepare the Room (Remove Objects & Baseboards)

The first step is always to prepare the room. You can do so by removing most objects and furniture in it – including baseboards. Then, vacuum the carpet and clean the underlay as much as possible. Place the spacers around the room to allow for an expansion gap for the wood.

Consider Installing a Plywood Layer

Installing plywood allows you to create an even and solid surface for the hardwood planks. Consider this option if the carpet underlay is thin enough and you’ve invested in high-quality hardwood planks that a bouncy subfloor can’t damage.

Lay the Planks Down Starting at One Corner

Once you’ve created a clean, even, and solid surface for the planks, you can start laying them down, starting from the furthest corner of the room. Use the tongue and groove system to interlock the planks and align the seams. The last wooden plank is likely to need cutting – you can do so with a saw or utility knife, depending on the kind of wood you’re using.

When starting the second row, remember to leave a gap to be filled with a section of a plank to create a more scattered and natural look. As you move down, ensure that the planks are interlocked and remove the spacers as the installation is complete.

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ReadyToDIY is the owner of this article. This post was published on May 9, 2021.

Can You/How To Put Hardwood Floor Over Carpet