If you’re installing a new floor or carpet in your home, you’ll need to provide it with greater protection.

That’s where underlay comes in.

What, exactly, is underlay?

Underlay, or underlayment, is a thin layer of material that’s put underneath your carpet or flooring, such as vinyl, laminate, and wood flooring.

When it comes to flooring, underlay can take the form of rubber, foam, felt, or fiber and it helps to insulate the floor as well as reduce wear and tear.

For some types of flooring, such as those made out of wood, underlay can help to provide a moisture barrier to increase the lifespan of your flooring.

With that in mind, let’s take a closer look at the underlay and how long it lasts.

Do You Need Underlay?

Attached Underlay

If you’re unsure of whether or not you need underlay, there are many good reasons to consider using it.

These include:

  • Increased comfort. Underlay serves as a cushion to make walking on the carpet or flooring much more comfortable.
  • Shock absorption. Underlay can work as a shock absorber, protecting the quality of your floor. If you imagine how many times you walk across the floors in your home, you’ll quickly see that underlay can help a lot in this regard.
  • Insulation with the use of underlay can help to create a barrier against noise.
  • Of course, underlay can help to insulate your flooring which will reduce your energy bills.

Common Types Of Flooring Underlay

There are different types of flooring underlay from which you can choose.

Let’s explore them in greater detail, starting with carpet underlay options.

Carpet Underlay

Polyurethane Foam

This is a very popular type of underlay that’s made out of recycled foam offcuts. Foam is comfortable and offers various density as well as thickness options. Best of all, if you’re installing the underlay yourself you’ll love how light and easy it is to work with.


Crumb rubber is dense and flat, which makes it useful if you have a lot of traffic in an area of the home. You can also get rubber crumb base underlay that has a felt top layer. This increases its comfort and durability, so it’s worth considering.


Sponge Rubber Carpet Underlay

Sponge rubber is comfortable and has durable spring retention.

You can get it in a variety of weights.


This is a blend of wool, synthetic, and jute materials that have been recycled. Felt underlay produces a dense and firm product with great insulation features.

Pre-Tackified Underlay

This is a self-adhesive underlay that’s recommended for when you want ultimate comfort and durability for heavy-use areas.

Hard Flooring Underlay

Now that we’ve looked at the common types of carpet underlay, let’s explore what underlay options there are for hard floors.


This is a type of underlay that’s meant to be put underneath an engineered hardwood floor. It doesn’t need a moisture barrier, which makes it easy to install, but it’s not the best idea for your home if you live in an area that’s prone to high levels of humidity.


This is a moisture-resistant underlay that works well underneath laminate and wood flooring. It’s easy to work with and install, which makes it great for beginners.


Plywood Underlayment

Plywood underlay is used for vinyl flooring.

It creates a smooth, even surface on which you can install your flooring. But, if your subfloor is not in great condition it’s important to repair this beforehand otherwise you won’t get the support you need from the plywood.

Underlayment Panels

These are commonly used when you install laminate or carpeting on a concrete slab. They are interlocking panels that work well to prevent moisture. They have the effect of lifting the flooring of the concrete to protect it.

Cement Board

This type of underlay is basically meant for porcelain, stone, or ceramic tiles. It’s resistant to mould while also being easy to cut and work with.

Floating Underlay

There are also types of underlay that are known as the floating underlay. These are not attached to the subfloor and come in cork and foam options. They create a buffer between the top floor covering and any imperfections that could be present in the underlying subfloor or existing floor.

However, it’s important to know that you shouldn’t use floating underlay to replace rigid underlay if you’re applying it over a subfloor. They are, however, best used when you’re putting down a new floor covering directly over an old floor that’s still in good condition.

As an example, you can put a layer of foam as an underlay when installing laminate floors over an existing tile or wood floor.

How Long Do Underlays Last?

The good news about using underlay underneath your floor or carpet is that it has a long lifespan. As long as it’s made with quality in mind, carpet underlay can last you for up to 25 years.

Wood and laminate underlay can also last for the same amount of time, but this does depend on how much foot traffic it experiences. One of the best and most durable types of underlay is crumb rubber.

If you’ve put the underlay in an area of the home where there’s lots of traffic every single day, then this will reduce the underlay’s lifespan a little bit. There are other factors that will affect how long your underlay will last.

  • Its thickness. Choosing thick underlay is better than thinner ones because it will take a longer time to flatten down from all the foot traffic it experiences on a daily basis.
  • Its exposure to heat and moisture. Both of these factors can reduce the lifespan of underlay. That’s why it’s important to consider the temperature and humidity your region experiences before you install a specific underlay.
  • Its materials. If your underlay is made of synthetic materials, it will usually take longer to disintegrate as compared to those that are made out of natural materials.

When Should You Replace Underlay?

Anti Slip Underlay

Seeing as though underlay will eventually start to become worn, and this might be sooner rather than later depending on the above-mentioned factors, you might be wondering when you should go ahead and replace it.

For carpet underlay, you should install it every time you put a new carpet in a room in your home, unless the current underlay you have is less than a year old or is in great condition.

Similarly, it’s a good idea to replace underlay when the flooring has been damaged or you’re about to change your flooring.

Tips For Installing Underlay Properly

If you’re not getting a professional to install the underlay in your home, then you’ll have to do it yourself. There are some important things to bear in mind during this process.

  • Allow for expansion and contraction. It’s easy to think that once you have your underlay you can just go ahead and install it, but this is a common mistake. You need to keep the flooring and underlay in the same room for about a full day so that the materials can expand or contract according to the temperatures in the room.
  • If you’re putting plywood underneath a vinyl floor, it’s important to position the sheets so that they’re perpendicular to the floor joists – don’t make them parallel to them – and stagger the seams.
  • When working with thick rubber or carpet padding underlay, butt the seams against each other so that the pieces are as close to each other as possible.
  • If you’re putting down felt underlay, it’s good to overlap the pieces slightly at the seams. However, some manufacturers will insist that you avoid doing this with their specific products, so it’s always a good idea to consult the product instructions before you go ahead to be sure you’re doing it correctly.

Related Questions

Can you reuse carpet underlay?

While it might seem convenient, it’s never a good idea to reuse carpet underlay. This is because of how it disintegrates with time and can accumulate dust and dirt.

How much does underlay cost?

You can expect to pay between £3.50 to £10 per square metre, but this depends on the insulation quality.


Using underlay beneath your carpets or flooring has many benefits. Underlay can also last a long time, provided you install it properly and treat it well. In this article, we’ve provided you with different types of common underlay products to consider as well as how to install underlay yourself.


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