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Do You Need Underlay for Vinyl Flooring?

Photo collage of different types of vinyl flooring.

Vinyl flooring is becoming an increasingly popular flooring option for homes and businesses. When laying it, however, an underlayment layer is highly recommended. Underlayment helps to level out the floor, protect the floorboards, and extend the life of the vinyl flooring.

Vinyl flooring was once thought of as a material that was only used in hospitals and work spaces. Until a few years ago, it was rare to see it used in homes or high-end retail spaces. Several new products are on the market today, however, that have made vinyl a great choice for a lot of homes and businesses. 

Installing this type of flooring is fairly new, however. While just about every contractor is familiar with installing carpet, wood plank, or tile, installing vinyl flooring is a new skill for many people. Fortunately, products such as vinyl plank are designed to be easy to install, and even people who have no experience with installing any type of flooring have been able to install vinyl plank on their own.

What Does Underlayment Do?

A male worker cutting underlayment for flooring.

Underlayment is actually a layer of material that is placed between the floor boards and the vinyl flooring. There are several different types of material that can be used for underlayment, and choosing the right one for your project will depend on a variety of factors. Underlayment does several different things.

One of its primary purposes is to level out the floor. Typically, floor boards will have small divets, gouges, adn it can sometimes be at a slight angle. Underlayment provides a layer of padding that “fills in” these imperfections and provides a level surface for the vinyl to be installed on top.

Because the vinyl flooring is being installed on a more level surface, it can help to equalize the pressure that is placed on the floor. This will help to extend the life of the flooring. Underlayment can also provide some limited sound proofing.

Depending on the material it is made from, it is possible to block over half the noise (and sometimes more) coming from an upstairs apartment. Finally, underlayment provides a physical barrier between the vinyl flooring and the floorboards. This means that liquid spills will be absorbed by the underlayment instead of the floorboards, potentially presenting thousands of dollars in damage to the floor.

Most underlayment materials have something to kill mold and bacteria, preventing organic liquids and excess moisture that can be trapped between the layers from causing big problems.

What Happens if I Skip Underlayment?

Adding a layer of underlayment is not a requirement, and it is possible to install vinyl flooring without it. Underlayment does add an extra cost to a project, and many people question if they really need it. If you choose to skip this step, however, there could be some consequences.

The biggest consequence will likely be an uneven feel to the flooring after it has been installed. Vinyl sheeting is some of the thinnest flooring available on the market, and some brands of vinyl plank aren’t that much better when it comes to thickness. Essentially, this means that the floor will feel as if there is a blanket stretched over the floorboards.

It may be possible to feel divots or gaps between floorboards, and very likely that the floor will have an uneven feel to it. If you are using a vinyl plank product that has a layer of underlayment on the back of each piece, however, this will be less noticeable. Buildings with very even floors or concrete slabs may also be even enough that underlayment is not entirely necessary.

Underlayment also provides a barrier to sound. Without it, floors installed on higher levels of a building will carry noise very easily to people living underneath. In a private residence this might not be such a big deal, but in an apartment or office building, skipping the underlayment could lead to some very upset first floor tenants.

In some places, city or county codes may require underlayment on second floors and above. Also be aware that skipping underlayment may mean that there is no barrier between the flooring and the floor boards. Spills of liquids will be able to seep through the cracks between boards, and without any underlayment, there is no way to prevent these liquids from reaching the floorboards and causing a range of issues from water damage to mildew.

What Types of Underlayment are Available?

There are several different types of underlayment that are available to businesses and homes. Each one has its own advantages and disadvantages, so make sure to choose the right one for your personal situation.

1. Foam

Rolls of foam for underlayment of laminate flooring installation.

Foam is one of the least expensive underlayments available on the market, and one of the most popular. If the floorboards are made of plywood, foam will work to fill in any cracks or divots. It also has the property of being able to self-level; it will automatically compress in areas where the floor rises and expand in places where the floor is lower.

Foam underlayment comes in rolls of varying thickness. When installing foam underlayment be absolutely sure that you have no moisture issues. This material forms a water resistant barrier, making it very likely that any water already on the subfloor will be trapped.

2. Felt

A close up shot of felt fabric sheets in various colors.

Felt is a really good choice for anyone who wants to use underlayment to help with sound issues. The type of felt sold for underlayment is denser than most types of foam, so it muffles noise better. Felt is also a good insulator.

These two reasons often make it an ideal choice for placement in apartments and shared office spaces. Be aware, however, that felt is fairly thin. That means that it won’t help as much with comfort and leveling out the floor.

Most contractors will use it in conjunction with foam, or select a type of vinyl plank that comes with a layer of foam insulation on the bottom.

3. Cork

A close up shot of a cork board serves as an underlayment on flooring.

Cork is another material that absorbs sound and water. That means it can be a good choice if you have minor moisture issues. It will absorb small amounts of liquid, but it will crumble if exposed to too much water.

Be aware that this all natural material will cost a lot more than foam or felt.

4. Plywood

A macro shot of a stack plywood for the underlayment of flooring installation.

Plywood underlayment is very stronger and does better with water than cork. This is one of the more expensive options, however, and it is only a good choice in rooms will weight will be evenly distributed. For example, plywood underlayment could potentially split if you plan on having a heavy piece of furniture in an area.

5. Particleboard

A close up shot of stack of sheets of particleboard.

Particleboard is less expensive than plywood, but still one of the pricier options on this list. It’s also fragile, it can split fairly easily. Be sure that there is an excellent subfloor beneath it to prevent this from occurring.

Also, don’t use particleboard anywhere near an area with moisture or it will rot.

6. Oriented Strand Board

A close up shot of an Oriented Strand Board also serves as a background.

Oriented strand board, otherwise known as OSB is a product that is similar to plywood, but isn’t quite as durable. It swells easily when exposed to moisture, so be very sure your subfloor is dry.

When Should I Install Underlayment?

Underlayment will be one of the very first things that is installed when putting in a new vinyl floor. After the old floor is torn off, the subfloor will be inspected. Any leveling or replacement of the boards will occur at this point.

Then the underlayment is placed on the floor.

Can I Reuse My Old Underlayment?

Old underlayment can be reused if it is in good condition. Typically, however, underlayment isn’t in good enough condition to be reused. This layer absorbs moisture and debris over multiple years.

It’s common to find it full of mold and other contaminants. Furthermore, new underlayment typically only adds a few cents per square foot of vinyl floor installation. It’s generally a good idea to replace your old underlayment.