The best foam carpet underlays

The Complete Guide To PU Foam Underlay

PU foam is now the most popular type of underlay on the market, handily outselling crumb rubber and sponge rubber alternatives year after year in the UK. But what makes it the default choice for fitters and customers alike?

In this guide, we break down exactly what ‘PU’ foam is and the benefits it will bring to your home, plus showcase a selection of the finest PU foam underlays you can buy today.

What is PU foam underlay?

Cloud 9 Carpet Underlay

The benefits of PU foam underlay

PU foam underlay is produced using polyurethane (‘PU’) foam, a versatile and resilient material known for its excellent cushioning properties.

Like all underlay, it’s designed to be installed between the subfloor and your carpet, providing additional support, comfort and insulation.

PU foam underlay offers a host of benefits that make it an attractive option for any home:

Enhanced comfort

Woman and baby walking on a comfortable carpet with underlay underneath

One of the primary reasons homeowners opt for PU foam underlay is the unrivalled sense of comfort it provides.

Its natural cushioning effect means it feels soft and plush underfoot, helping transform any room into a cosy and welcoming space.

Warmer rooms

Man turning down the temperature on a room thermostat

PU foam boasts excellent thermal insulation properties, helping to keep your home warmer in the winter and cooler in the summer.

The upshot is potential savings on your energy bill, as your central heating system won’t have to work as hard to maintain a comfortable temperature.

Noise reduction

Woman relaxing on chair in a peaceful home

If you live in a busy household or a noisy apartment block, PU foam underlay can help. Being a natural insulator, it is extremely effective at absorbing sound, reducing the transmission of noise between floors and making your home quieter and more peaceful.

Our highest-performing acoustic underlays are all made from thick PU foam.

Wide range of choice

Two rolls of PU foam underlay

PU underlay comes in a huge range of thicknesses, densities and price points, meaning there is an option for every home and renovation budget.

Similarly, there are specialist options available for all your specific needs, whether you want a product compatible with underfloor heating systems, something suitable for double-stick installation or something to help soundproof a room.

Environmentally friendly

A recycled roll of PU foam underlay

PU foam underlay is predominantly made using offcuts of old mattresses, sofa cushions and the like, with up to 85% being recycled materials.

Not only that, a PU foam underlay will typically last between 10-15 years, depending on the quality of the product, meaning you won’t have to replace it often. Plus, when the time comes, there are specialist companies that will recycle it for you at the end of its lifespan.

All of this combined makes it an excellent option for environmentally-conscious homeowners.

Ease of installation

Man fitting pu foam carpet underlay in a room

PU foam underlay is lightweight and easy to handle, making it a DIY-friendly option for those who want to try fitting underlay themselves.

Professional fitters like it for much the same reason – it can be cut quickly and easily to fit any room shape or size, plus bending it over stairs is a doddle.

Drawbacks of PU foam underlay

While PU foam underlay offers many benefits, there are a couple of things you should be aware of:

Sensitivity to moisture

PU foam can be susceptible to moisture, which means it may not be the best choice for areas prone to dampness. However, some modern versions now incorporate an in-built vapour stop barrier, which negates this issue.


PU foam cannot compete with rubber underlay when it comes to durability and longevity. The latter is extremely dense and highly resistant to compression under heavy loads (whether that’s footfall or furniture), which is why it’s often used for commercial applications.

However, this density comes at the expense of cushioning, which is the reason why PU foam is so much more comfortable underfoot and better suited to residential homes.

So long as you opt for a PU foam underlay with a density of 100kg/m³ or more, you will never have an issue. However, you may still want to consider going for a thinner crumb rubber or sponge rubber underlay for high-traffic areas such as stairs and landings, which get a lot of wear.

Choosing the right underlay

When choosing a PU foam underlay for your project, consider the following to ensure you pick the right product for your needs:

  • Thickness: thicker underlays offer better cushioning but can be more expensive. Consider the level of comfort you need and the floor height difference between rooms before pulling the trigger.
  • Density: higher density underlays provide better support and durability, especially in high-traffic areas like stairs and landings. This isn’t as much of a consideration in rooms designed for relaxing, such as bedrooms and lounges.
  • Room usage: think about the room’s primary function. Bedrooms and living areas will benefit from a softer, thicker underlay, while hallways and stairs require something denser and more durable.
  • Specific needs: whether you want something to reduce noise or heat loss, have underfloor heating installed or need a double-stick underlay for a plant-fibre floor covering, there are specialist underlays to deal with every individual requirement now.

The best PU foam underlays

With so many options available these days, the choice can be overwhelming when it comes to buying underlay. Yet fear not as our expert team has hand-picked their favourite products across several categories so you can feel confident in your purchase.

Luxury: Wilsons Plushwalk 12mm

Wilsons Plushwalk 12mm Memory Foam Carpet Underlay Close Up

If the budget will stretch and you don’t want to compromise, Plushwalk 12mm is the only option. This revolutionary underlay has become a byword for luxury in our industry and is actually made using virgin memory foam (like your favourite pillow), giving it an unrivalled cushioning sensation.

But that’s not all. Plushwalk is also our most insulating underlay (3.50 TOG) and the best at reducing impact noise (49dB). It perhaps comes as no surprise, seeing as it’s a whopping 12mm thick.

Value for money: Tredaire Dreamwalk

Treadaire Dreamwalk 11m Underlay Close Up

Dreamwalk forms part of Tredaire’s Premier Collection, but you’d never guess it from the price point. At just £4.45m² (time of writing) it outperforms much more expensive underlays, delivering a sumptuous 11mm thickness, 110kg/m³ density, 3.13 TOG and 43dB impact sound reduction.

A genuine bargain and the definition of affordable luxury. Our default recommendation for most customers.

Budget: Tredaire Brio

Tredaire Brio 8mm Underlay Close Up

If budgets are tight (we all know what renovating can be like) then you need an affordable underlay that doesn’t scrimp on quality. That’s exactly what you’re getting with Tredaire Brio.

Priced at a lowly £3.38m² it punches well above its weight with 99kg/m³ density, 2.18 TOG and 32dB sound reduction ratings. At 8mm thick it can also be used across the home, including on stairs, which helps reduce waste and makes it even more economical.

Seem too good to be true? Don’t worry, you can trust Brio to go the distance – Tredaire even guarantees it for the serviceable life of your carpet.

Sound reduction: Tredaire Softwalk

Tredaire Softwalk 9mm Underlay Close Up

If you live in a noisy home or apartment block then let Tredaire Softwalk be your saviour. This exceptional underlay reduces impact noise by 41dB even though it’s only 9mm thick (to put it in perspective, no other underlay below 10mm gets above 40dB).

Yet the best thing about this size-to-performance ratio is that Softwalk can be used across the home, including on stairs, so you can even dull the noise of your little cherubs constantly running up and down them.

This is your shortcut to a quieter, more peaceful living environment. A TOG rating of 2.69 and a density of 118kg/m³ are just a bonus.

Underfloor heating: Wilsons ThermalStream

Wilsons Thermal Stream underfloor heating carpet underlay close up

Underfloor heating underlays are typically thin and dense, offering little comfort underfoot. But Thermalstream bucks the trend. Made using 10mm thick foam, this innovative product from Wilsons Underlays sees hundreds of holes punched through it, giving it a TOG rating of just 0.80 and enabling heat to transfer quickly and evenly across your floor.

The result is exceptional comfort and a sense of luxury you just don’t get with rubber alternatives.

Durability: Cloud 9 Contract

Ball & Young Cloud 9 Contract 8mm Underlay Close Up

PU foam is so comfortable underfoot because it’s naturally spongy and compresses easily. Yet this is the opposite of what you want in commercial environments or areas of high footfall. So, if you’re looking for a foam underlay that can stand up to increased wear and tear then Cloud 9 Contract is one of only a handful that can take a beating and bounce back (figuratively and literally).

This 8mm thick underlay manages to pack in 167kg/m³ of foam, giving it exceptional durability without sacrificing comfort. And with a 2.00 TOG and 36dB sound reduction rating, it’s a product that will keep heat in and noise out.

Not only that, Cloud 9 Contract is also suitable for double-stick installation, allowing it to be used with natural plant fibre carpets such as sisal, seagrass and jute.

Need further help?

It’s clear to see why PU foam has quickly become the industry default, with a number of exceptional products now available across the pricing spectrum.

If you still need help picking the right underlay for your project don’t hesitate to get in touch with our expert sales team at