Underlay Buying Guide

When it comes to buying flooring, underlay can sometimes be an afterthought. You don't see it after fitting day and so it falls off the RADAR.

We want to change that! Underlay is fundamental to getting the most out of any flooring. It can improve how your flooring feels underfoot, insulate sound and heat and help your flooring look good and last longer. It may be a bit of a behind-the-scenes hero, but underlay is always worth the investment.

Because it's so important, we want to break down the basics of underlay, so you feel more confident about the buying the right one for your home and flooring type.

Basically, if you're buying a new floor, you probably need new underlay. Fitting new floors over worn underlay can wear it down unevenly, meaning high traffic areas show wear quicker than they would with new underlay. Older underlay also absorbs dust and dirt over the years, so new flooring is a great opportunity for a deep clean and a fresh start with new underlay.

Why do I need underlay?

Underlay is the foundation of your flooring and can be crucial to making sure it's a good investment.

Reasons to love underlay:

  1. The right underlay can extend your flooring's life between 30-50%!
  2. It adds comfort and cushion underfoot.
  3. It acts as a shock absorber, preventing excess wear and protecting your floor.
  4. It helps with soundproofing and is a good barrier against noise.
  5. Underlay is a great insulator and can help save money on your energy bills.

Underlay for Carpets

Carpet underlay acts like a shock absorber, making sure your carpet bounces back from wear and footfall. This means your carpet will look better for longer, as the pile won't flatten so quickly. 



Polyurethane or PU for short is typically the modern day go-to choice for most home installations with carpet, this is primarily down to great performance expectations at a much keener cost per square metre, compared to the historical rubber underlays which generally are much more expensive per metre with very little added benefits. PU underlays are made mostly from recycled foam found through mattresses, sofas and automotive interiors. 


Our recommended PU underlay is: Cloud 9 Caviar & Crystal

Sponge rubber


Sponge Rubber underlays are the perfect choice for any installation where under-floor heating is in place. With some ranges offering fantastic heat transfer properties they will ensure you allow the most amount of heat to pass through the underlay and up into the carpet and into the room. This is where most PU underlays will struggle, due to mostly very high tog ratings.

To learn more about under-floor heating and how your underlay choice will play an impact on the working efficiency of your heating system be sure to read our Underfloor Heating Guide.

Underlays for Hard Floors

Hard floors like laminate, wood flooring or luxury vinyl need underlay to help to protect the joints in the planks or tiles. This helps prevent flexing and makes sure your floor last longer. Here’s a roundup of the different underlay suitable for each type of hard flooring.

Luxury Vinyl Tile


Underlay for luxury vinyl tile is made off dense rubber. A slightly tacky top side keeps the vinyl from slipping after installation. It’s also great for use with underfloor heating. This underlay improves sound insulation and reduces in-room noise by as much as 30%.

Engineered Wood


Designed to support and cushion wood flooring, underlays for engineered wood are mostly made from recycled car tyres. Most also utilise a foil top which acts as an insulator and vapour barrier protects against the possibility of rising moisture.



Ideal for underfloor heating, Heatflow underlays are made of rubber with a low tog rating. Heat can flow easily into your room for increased energy efficiency and lower energy bills. There’s a version of this underlay for carpet or wood flooring, and both give great sound insulation.

Tog Ratings

We’ve all seen tog ratings when buying bedding, but they apply to the thickness, density, and composition of carpets and underlay too. A tog rating is just a measure of heat insulation and is super relevant when it comes to flooring.

A low tog rating is better for underfloor heating, as it means more heat will flow into your room.  A tog rating of 2.5 is the maximum we’d recommend for underfloor heating. That means the combined rating of the carpet and underlay!

A higher tog rating means greater levels of heat insulation. This is ideal for conventional heating systems, as a lot of heat can be lost through the floor. A high-tog underlay will keep your room warmer and cosier.  

To learn more about tog ratings, please be sure to read our Tog Rating Guide.