Choosing Between Rubber and Foam Underlay: A Comprehensive Guide 

Laying a new carpet? Have you considered which carpet underlay – rubber or foam? It might sound like an unimportant question, but your choice in underlay can affect how long your carpet lasts, how comfortable it is to walk on, how warm your home or workplace is, and how quiet your rooms are.  

Both rubber and foam underlay have their own advantages and drawbacks, and which one is right for you will depend on your budget, your space, and what kind of carpet you’re going for.  

Understanding Foam Underlay  

Foam underlay, or PU foam underlay, is a lightweight, soft material often made from recycled furniture foam. Thanks to its softness, it’s able to conform very nicely to any irregularities in your subfloor, as well as providing superior sound and thermal insulation.  

It also means that PU foam underlay is very comfortable to walk on, and could be a good way to compensate for a thinner carpet, or even make a soft carpet feel even more luxurious.  

Exploring Rubber Underlay  

Rubber underlay, on the other hand, comes in two main kinds – sponge rubber or crumb rubber. Sponge rubber is almost like a rubbery alternative to foam, but not quite as soft or light. Crumb rubber, often made from recycled car tyres, is made from small chunks, or crumbs, of rubber adhered together into sheets.  

Most British homes feature sponge rubber underlays, and it’s been in use for decades in the UK construction industry, but newer alternatives are offering advantages it struggles to match.  

Carpet Underlay – Rubber or Foam?  

There are a few key differences between rubber and foam underlays, with variations in costs, ease of installation and maintenance.  

Which underlay suits you best will depend on your budget, your use case, and how comfortable you want your floors to feel.  

Sound Insulation and Impact Resistance  

With differing material properties, come variations in ability to retain heat, dampen sound, and withstand impacts.  

PU foam underlay, now used largely as the industry standard in UK homes, offers much greater heat and sound insulation than its rubber alternatives, thanks to its dense, soft nature. It’s this same softness that makes it so comfortable underfoot too.  

Alternatively, rubber underlays don’t offer quite the same levels of sound and heat retention, but shine when it comes to wear resistance.  

Because of these contrasting properties, it’s possible that you might want to consider a mixed use of both rubber and foam, with rubber used for high-traffic areas such as staircases, and foam used for comfort spaces such as bedrooms or your living room.  

Moisture Protection and Subfloor Compatibility  

If you have a solid, cold subfloor such as concrete or stone, you may be more susceptible to issues with damp. In addition to fitting a damp-proof membrane underneath both your underlay and your carpet, you may want to look for an underlay that also features damp-proofing. 

Some underlays will also be able to compensate more effectively for an uneven or cold subfloor, for example, PU foam underlay is better able to conform to irregular surfaces and offers much greater heat insulation, keeping your feet that extra bit warmer, regardless of how chilled your subfloor might be.  

So, when deciding which carpet underlay – rubber or foam – remember that rubber will last longer, and offer greater impact resistance, but PU foam will be softer, warmer, quieter, and cheaper. Rather than deciding to fit your whole home or workplace with one or the other, it may be worth also considering a mix of the two, based on how different rooms will be used.  

For more information about which carpet underlay will suit you best, and to discover competitive prices and customised cutting for PU foam underlay, make sure to fill out our online form, call us on 0116 284 1222, or email us at