Vinyl Plank Flooring Image

Do I Need Underlayment to Install Vinyl Plank Flooring?

Whether you need an underlay or not will depend on the type of vinyl plank flooring you intend to install, what the subfloor is made of, and your personal preference.

Some vinyl flooring will require a vapor barrier, depending on your subfloor construction.
While most vinyl flooring has been designed to be installed directly on top of the subfloor and not require underlayment, you may require a vapor barrier.

You may also opt for a thin underlayment to help with noise reduction or to simply offer some insulation for the colder months.

In this article, we will look at when an underlay is or is not required for vinyl plank flooring.

Your Subfloor

Before deciding to go ahead with any flooring project you will need to ensure that your subfloor is in great condition. It will specifically need to be level, free of damage, smooth and clean.
If your floor is missing even one of these components you should not be installing vinyl flooring until the appropriate corrective measures have been taken.

If you fail to correct your subfloor before installing vinyl the manufacturer will not honor any guarantee given, and your new floor may need to be replaced far sooner than you had hoped.

A subfloor in good condition will not necessarily determine whether you need underlayment or not, but it should be first and foremost on your mind when deciding whether to install vinyl plank flooring at all.

If you intend to install vinyl over floorboards, we recommend laying down plywood first to ensure your floor is level and smooth. Additionally, if you plan to install vinyl over tile, you will need to fill in the grout lines for the same reason.

We will look at each subfloor type and whether it requires (or does not require) underlay as we discuss the different types of vinyl flooring below.

Type of Vinyl Plank

There are four popular types of vinyl plank flooring and each type recommends slightly different approaches when installing the planks.

Some work well with underlayment and for others simply using it could ruin your vinyl flooring installation.

Click Lock Vinyl Plank Flooring

This type of vinyl flooring is the most similar to laminate flooring. The ‘click lock’ refers to how the flooring is joined together. This type of installation is what is commonly known as a floating floorClick Lock Vinyl Underlayment.

The flooring is not glued or nailed to the subfloor, but instead is installed unattached on top of the subfloor.

Click lock vinyl flooring can be bought in thicknesses ranging from 2mm to above 8mm, with only the higher end of that (over 4mm) being able to take the strain of additional padded underlayment.

When a padded underlayment is used below the flooring it will bend when walked on, thinner vinyl’s click lock system will not be strong enough to take this strain, and will likely break under the pressure.

In this instance, it is better to lay the flooring with no underlay.

Concrete Subfloor

If you intend to install your vinyl flooring on a concrete subfloor, you will likely require vinyl underlayment that includes a damp-proof membrane. This will reduce the possibility of moisture getting into your floor, and provide some insulation for the colder months. If your vinyl chosen is particularly thin, you will need a vapor barrier, but should not add additional underlay.

Wood Subfloor

If you intend to install your click-lock vinyl on a wooden subfloor you will not require a damp proof membrane, but may want to include some vinyl underlay for added cushioning and a certain degree of sound reduction.

Existing Flooring

If you are installing your new floor over existing tile or linoleum you may want to consider some vinyl underlay for cushioning and sound reduction, but will not require any further moisture barrier.

Wood Plastic Composite (WPC) or Stone Plastic Composite (SPC) Vinyl

The majority of WPC and SPC vinyl flooring can be installed directly over the subfloor, or make use of an underlayment. In fact, many of the brands include an underlayment attached directly to the vinyl boards so further underlay will not be required.

WPC Vinyl Flooring Underlay ImageMost WPC and SPC vinyl will also make use of a click-lock system for installation.

Each and every manufacturer will provide you with instructions on how their particular flooring should be installed and will include details on whether a separate underlay will or will not be required.

If you are installing your WPC or SPC vinyl on a concrete subfloor it is advisable that you use a vinyl that includes this vapor barrier, or install the flooring over a separately bought vapor barrier as a minimum.

WPC and SPC due to their stability and construction can usually be used alongside underlay, or be installed directly over the subfloor.

Glue Down Vinyl Flooring

Glue Down Vinyl Flooring Underlay ImageGlue-down vinyl flooring will never require underlay regardless of your subfloor. This type of vinyl flooring must stick solidly to the subfloor with adhesive so underlay can not be used.

For those installing over a concrete subfloor, you will need to ensure that your subfloor has been properly cured. Specifically that it was poured more than 60 days previous.

Whether your floor is new or not you should test the moisture content with a moisture meter. If your reading is no more than 3 pounds per 1,000 square feet in a 24 hour period your floor is ready to be installed.

Loose Lay Vinyl Flooring

Loose lay vinyl plank flooring does not need underlay, but if you’re installing over concrete the subfloor should be checked for excessive moisture.Loose Lay Vinyl Plank Flooring Underlay Image

You should test the moisture content with a moisture meter. If your reading is no more than 3 pounds per 1,000 square feet in a 24 hour period your floor is ready to be installed.

The loose lay system involves vinyl planks or strips that are laid in place. These strips have a rubber backing which keeps them in place by sticking to the subfloor by friction only.

Whether this installation method is good or not is for another time (spoiler: there are pros and cons), but it definitely does not need nor want any underlayment.