14 August 2023

Our Ultimate Guide to Underlay

When choosing flooring or carpets for your home, deciding which underlay you should have is not often something you need to consider. This decision is often decided by your installer.

Understanding the types of underlay available to you and why it is important can save money, time and prevent any regrettable mistakes. Here’s our ultimate guide on all things underlay.

What is underlay?


‘place something under (something else), especially to support or raise it’

And that is exactly what it does! Whether you choose a carpet, laminate or wood flooring, underlay provides insulation and comfort.

Not all flooring types require underlay. As a general rule of thumb, if your flooring is glued down, it isn’t required.

The only exception to this is Rigid Core LVT flooring. This is LVT (luxury vinyl tile) flooring with a stable core and click installation method. Rigid Core has an underlay pre-attached, saving time and money.


It is well known that carpet requires underlay but not all carpets require the same type.

Carpet underlays typically come in 9mm, 11mm and 12mm but there are other variations. Having the thickest, isn’t always necessarily the best option. We recommend the following:

Carpet  Thickness Type
Cut Pile (Wool Twist, Wool, Man Made) 9mm (stairs) 11mm, 12mm PU, Felt, Memory Foam Rubber Crumb
Sisal 9mm, 5mm Rubber Crumb, Double Stick
Loop Pile 9mm PU, Felt, Rubber Crumb
Flatweave 9mm PU, Felt, Rubber Crumb

PU (Polyurethane) – The foam used in PU is either from off cuts or trimming from other processes. It is shredded and then granulated into smaller pieces and then mixed with a binding agent, before moulding into a large roll of a pre-defined density. PU typically comes in either 11mm or 9mm, but is manufactured in a number of different thicknesses. One of the cheapest options; PU is most commonly used in residentially properties.

Memory Foam – A PU underlay with memory foam incorporated into the structure of the material. This provides a dense yet soft feel underfoot and ensures longevity in the appearance of your carpet. It also provides good sound proofing properties.

Rubber Crumb – As the name suggests, this is made from crumbs of rubber, that are bonded together. Dense and durable, rubber crumb is a great option for high-traffic areas. Made from 100% recycled material; one car tyre makes 1 m2.

Recycled Plastic – Made from recycled plastic bottle’s, it can be 100 % recycled after use too. Naturally breathable, flame resistant and no harmful VOC content. Available in 9mm and 11mm, providing comfort, warmth and softness underfoot.

Wool Fibre – 100% recyclable and natural. Provides great insulation properties and a softness underfoot. More commonly used in the commercial sector; it is still widely used for residentially properties too. The natural wool fibres, provide great insulation and sound proof properties. Naturally breathable, flame resistant and no harmful VOC content.

Laminate/ Wood Click

When installing laminate or wood flooring (click installation); there are a number of different types of underlay to chose from. Each installer will have their preference. Most manufacturer’s will have their own branded underlay to provide a suitable option depending on your requirement. Essentially, as long as you use an underlay specifically for a laminate or wood, your flooring will perform correctly.



Barrier – A light weight, PU Foam roll. Available in different thicknesses but generally comes in 3mm. Barrier can be used for laminate and click wood floors. It prevents moisture migration from subfloors, by providing a barrier; hence the name!

Fibre Boards – A light dense board made from wood fibre. Typically 5mm thick. Fibre board can used for laminate and wood click flooring. Although it has good sound proof properties it will not prevent moisture migration from subfloors.

Rubber – Typically 3-4mm thick, rubber has great tog and sound proofing properties. This type of underlay usually comes will a foil attached. This provides a vapour barrier to protect against moisture migration from the subfloor.

Thermo and sound proofing – As mentioned above; there are plenty of manufacture’s producing all types of underlay to help provide the right product for your requirements. You will find plenty of options specifically designed to help with insulation or sound proofing. However you may find that some options naturally provide these functions.

Which ever flooring you choose, it always best to check with the manufacturer that you have the correct underlay for your flooring/carpet, room and requirements.

Our guide to underlay and why it shouldn’t be overlooked


Elka Duo Lay


Comfort Lay



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