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Guide to buying underlay

Underlay buying guide 

 Underlay is a fundamental part of a new carpet or floor and should never be overlooked. It is an integral component that determines how your flooring feels, looks and more importantly, how it wears. It’s recommended to buy new underlay whenever you replace your carpet or flooring, rather than using the existing underlay. It is massively important when purchasing new flooring to consider which underlay is best for your needs and requirements. As a leading online flooring retailer, we like to make sure we are up to date and know all there is to know when it comes to flooring accessories and underlay. The correct underlay will improve the comfort level of your new flooring and increase its lifespan by up to 50%. A good quality underlay will provide thermal insulation, reduce noise and make your new flooring feel softer underfoot. We like to use the example of a car without suspension, it would rattle itself to pieces in no time at all. In the same way, underlay acts as a shock absorber to your carpet or flooring and will absorb impact, preventing premature wear. If your underlay has only been down for a short time then you can get away with reusing it, but older underlay is more likely to show signs of wear, especially in busy areas of the home. To reuse old broken-down underlay can cause ridges in your carpet and cause it to wear unevenly. Overtime the cells in the underlay will break down and can harbour dirt and bacteria so should be replaced when installing new carpets and flooring.

Here is our guide to choosing the best type of underlay for your new floor.

Why do you need underlay? 

Underlay is comfortable to lie on

Underlay is an important when replacing your carpet or flooring. It should not be overlooked or dismissed as a waste of time. There are numerous benefits and you should never consider going without underlay. The benefits of the best type of underlay include:

Noise reduction

Underlay will help soundproof, so it's perfect if you have a busy household!

Your flooring will look better for longer

Good quality underlay will prevent premature wearing and keep your floor looking new for longer. As the underlay acts as a shock absorber, your flooring or carpet will sit better and take more wear.

Acts as an insulator 

The best type of carpet underlay will reduce your energy bills as it will keep the heat in your room. If you plan on living in your property for longer, consider investing in a good quality thermal underlay.

Adds comfort

Underlay adds a level of cushioning underneath your carpet, laminate, engineered wood or luxury vinyl flooring making it feel more luxurious and softer underfoot

Your carpet is easier to clean

As the carpet pile is protected, the carpet is easier to clean and dust will be removed more easily.

It is worth pointing out that there is more than one sort of underlay. Continue reading this guide and realise the differences in underlay and discover the one that will suit your room and flooring type best.


Types of underlay 

There is a hugely diverse range of underlays on the market for use with different flooring types and for different applications or areas which vary in their structure and composition, depending on what we need from them. In brief, carpet underlay acts like a shock absorber, helping carpets bounce back from heavy wear and footfall. Your carpet will look better for longer because the underlay prevents premature wear. Underlay for laminate flooring and luxury vinyl tiles helps to protect the joints in the planks or tiles, reducing any risk of flexing to extend the life of your flooring. A good quality laminate flooring underlay will absorb sound and prevent the hollow tapping noise that you will get without an underlay.

Purple Underlay - Polyurethane Foam


PU foam is very popular choice as it gives a lovely soft feeling underfoot. Offering impressive heat and sound insulation, polyurethane underlay is made from recycled furniture foam, so it's an environmentally friendly choice which can be recycled again after use.

PU foam is available in various thicknesses and densities depending on budget. The thicker and denser the underlay, the better the insulation, luxurious feel and noise reduction. Being inherently comfortable and durable makes it a favoured material for carpet underlayment. It is also lightweight, so it’s easy to carry and fit



Waffle rubber underlays are the most traditional form of underlay and have been around since the 1950s. They are tremendously comfortable and other underlays cannot replicate the same feel underfoot. They are also extremely good at minimising both impact sound and floating sound between rooms. The pocket like construction allows more air to flow when vacuuming which keeps your carpet cleaner.

Waffle rubber underlays are incredibly versatile and cover more applications than any other types of underlay. Available in a range of thicknesses this type of underlay is suitable for all areas of the home. Why not try a super thick variety like ‘colours red’ to bring extravagant luxury into your lounge or bedroom?

Crumb Rubber

Extremely dense and durable, crumb rubber underlays are the number one choice for hard wearing, high traffic and very large areas including commercial premises. They are great at reducing impact and airborne noise and are the only type of underlay that can achieve 100% recovery from loading, therefore no indentation marks from heavy furniture. 

Crumb rubber will extend the life of a carpet and improve insulation. This high-performance rubber underlay is kind to the environment, manufactured from granulated used car tyres, which creates a tough, highly durable, dense underlay. Every square metre of crumb rubber underlay contains the rubber of at least one car tyre! 

Easy fit underlay

Easy Fit

Comfort 2mm underlay can be used on any sub-floor that is level and dry such as floorboards, chipboard, hardboard, plywood or concrete

designed specifically for use with laminate or wood flooring. This easy to install underlay will help to cover minor sub-floor imperfections of up to 1.5mm and is suitable for general domestic use.


Outdoor underlay 

Our outdoor underlay provides a spongy cushioning for your artificial lawn or outdoor carpet, it also conceals imperfections that could transfer through to the grass or carpet once it’s been installed.

Made from high-density foam (closed-cell polyurethane), it’s dense 10mm thick construction offers great underfoot comfort. It comes pre-punched with drainage holes and will help to prevent mould or mildew in damp areas 



This heavy duty, highly dense synthetic rubber based product is designed for wood and laminate flooring. Not only is it a great insulator it can also reduce in room noise by up to 30% and contains a built in moisture barrier. 

With its excellent resistance to compression, this underlay Prevents the over straining of wood and laminate boards so your joints will stay secure even in high traffic areas. Simple, quick and easy to install, suitable for heavy domestic and light commercial use.

XPS Foam Underlay

XPS Boards

Xps foam underlay is an eco-friendly, lightweight insulation board manufactured of fully recyclable material. It is produced from foamed polystyrene and will not deteriorate. It is incredible easy to install and when you lay XPS boards as an underlay any heat from your room or floor will be reflected back towards the floor surface.

It is not only in flooring underlayment, but also in a vast variety of other applications in the construction industry including, wall insulation, under concrete slabs and in roofs. 


Expanded Polyethylene

Expanded Polyethylene, known in the trade as EPE underlay is a lightweight, semi-rigid, flexible closed cell foam, most commonly used in packaging, for impact and shock absorption, vibration dampening, and surface protection. It is also used in some gym floor mats and foam gym equipment. 

As a high performance acoustic underlay, it is suitable for use with solid wood, engineered wood and laminate flooring. It is easy to fit and the fact that it has a low thermal resistance (TOG rating: 0.9), makes it also ideal for use with underfloor heating systems. It comes with a built in DPM therefore suitable to use on concrete sub floors.

Browse our underlay range

Luxury Vinyl Flooring 

This underlay made specifically for use with luxury vinyl tiles is constructed from dense rubber. The underlay is loose laid over the sub floor or existing flooring, the new flooring is then positioned on the top side and will not slip, thus preventing over straining of the joints.

It offers excellent sound absorption and thermal insulation. Smooths out minor sub floor imperfections reducing installation time. Environmentally friendly and is 100% recyclable. Installation is quick, clean and simple.


What is TOG rating? 

Pet-friendly flooring

You may have noticed TOG ratings listed on products such as duvets or sleeping bags but it is just as relevant when it comes to underlay. What exactly does TOG mean? TOG stands for ‘Thermal Overall Grade’, which is a unit of measurement used to calculate the thermal insulation of a product, usually in the textile industry.

Thickness, density and structure dictate the tog rating of both carpet and underlay. They vary widely so you need to be sure which is right for you. In a household with a conventional heating system it is a good idea to use an underlay with a higher tog rating, this will provide a greater level of insulation as less heat will escape through the floor ensuring a cosier feel.

However If underfloor heating is being used then the underlay should be suitable for use with the underfloor heating product and therefore have a low tog rating such as 0.35 tog. This is because the heat needs to be transferred from the underfloor heating system through the chosen floor covering and into the room, so the least thermal resistance is needed. Therefore a lower tog rating will provide a better performance for your underfloor heating system.

According to tests carried out by the UHMA, carpets and underlay with a combined rating of 2.5 tog can be used with underfloor heating without impairing its efficiency.

Different floor coverings require different types of underlay with different tog ratings:

Type of floor covering

Recommended underlay TOG rating

Laminate Flooring

 1.0 tog


over 2.5 tog

 Underfloor Heating

 0.35 tog or below


Choosing carpet underlay 

Underlay should not be viewed as optional. It is an essential part of the flooring, crucial to the comfort and durability. Choosing something of good quality will help prevent the carpet pile from flattening, ensuring it retains its appearance for longer.

Should I use old underlay?

Your carpet will need firm and consistent support to sustain maximum performance. Fitting old underlay can reduce the life of the carpet as it won’t provide the right support, resulting in wear showing quicker.

Is soft or firm underlay better?

Firmer underlay gives added protection to the carpet against the hard sub floor during normal walking. It also reduces indentations from heavy furniture and helps prevent creasing by limiting vertical movement and stretching of the carpet. Soft, low density underlay doesn’t provide adequate support in heavy wear or high traffic areas, as the carpet pile is effectively squashed against the sub floor, accelerating wear and reducing appearance. An underlay that is too soft will collapse under the pressure, distorting the carpet backing and preventing good recovery. Any indentations will be more severe and movement increased, especially where heavy furniture is present and moved around the room occasionally.

Should I use Underlay for stairs?

The choice of underlay for the stairs is especially important. Firmer underlay is often needed to give a good cushion and support the carpet, especially at the edges where they get the most wear. Choosing a good quality, new underlay will therefore help prolong the life of your new carpet.

What underlay does Flooring Direct recommend?

First of all we strongly recommend using an underlay. When purchasing a new carpet and underlay together on a tight budget we feel you would get a better, more cost effective overall result if you opted for a lower priced carpet in order to be able to purchase a better quality underlay. It is always best to speak to us directly for advise and to request samples of underlay and carpet so you can try them in the comfort of your own home to test how they feel underfoot.

Choosing flooring underlay 

Every DIY handyman knows: if a jobs worth doing, its worth doing properly. This is no different when installing a new laminate floor. After all, there is one step that is more crucial to success than any other if you are planning to put in new laminate flooring and that is, Choosing the right underlay for the job.

Which type of underlay to choose?

At Flooring Direct you will find a suitable type of underlay for any kind of application. Take a minute to work out exactly what you need.

If the room which you are replacing the floor in is a room which you do not use very often like a spare bedroom or attic room, you could go for a budget friendly basic underlay like our Comfort White.

Installing a new floor in a living room or kitchen will require a harder wearing underlay suitable for high traffic areas and one that will absorb sound such as our Comfort Gold.

Maybe you want to keep the noise down to the absolute minimum in order to create a peaceful working environment, or perhaps for a nursery where its crucial to not wake baby, in these cases Timbertech Plus is exactly what you would need.

If the floor onto which you will be laying your laminate has some undulation, or if you plan to install it on top of an existing tile floor, our Sonic Silver underlay is your best option, this underlay smooths out every irregularity in the subfloor to a maximum of 3mm.

Should you be installing a new floor in a basement or other areas prone to moisture, your underlay will need a built-in moisture barrier. A moisture barrier usually comes in the form of foil or plastic, we would recommend using Sonic Gold. Not only does it have a foil backing, it also offers good thermal values.