What is the purpose of the carpet underlay?
The main purpose of the underlay is to provide the carpet extra wear resistance and to prolong the carpet's life. The other purposes of the underlay are to provide underfoot comfort, dust suppression and sound and thermal insulation.
Do I need underlay?
If your new carpet has jute backing, secondary backing, action backing or is a woven carpet , then the answer is yes, unless your intention is to fully adhere the carpet to the subfloor. The only drawback when not using underlay is that you will not be able to enjoy the luxurious feel and thermal and sound insulation that the underlay provides.
If your carpet is foam, silicone or rubber backed, then it must be installed straight on the floor, without underlay, using an appropriate carpet adhesive. This sort of carpet is usually used in a commercial environment.
Can I reuse my old underlay?
You can, but you will be making a false economy. Even if it looks fine when you install the carpet, it could fail during the lifetime of the new carpet. Furthermore, carpet manufacturers guarantee that their products will perform as well as advertised, only if the carpet is installed on new, good quality underlay.
What types of underlay are there?
PU foam underlay
Pu foam underlay is amongst the most popular type of carpet underlay sold today.
PU (Polyurethane) is a very resilient material. It has been used for years in good quality sofa seat cushions, for its ability to keep its shape and elastic properties. PU foam underlay is made from recycled material, making it environmentally friendly and relatively cheap.
The market leader is Cloud 9, with a stitched paper backing and it comes in 7mm, 9mm and 11mm thickness. Other PU foam underlays are Cosi, Seventh Heaven, Blue Heaven and Soft as a Cloud.
There are two main types of rubber underlays: sponge rubber and crumb rubber.
Felt underlays are widely used mainly in commercial environments, like pubs, restaurants and cinemas. It is very resilient and environmentally friendly. It is made from wool and artificial fibres that would otherwise end up in landfill sites. It is suitable for use in high traffic areas like stairs, landings, halls and in any place where the carpet takes a heavy use.
Combination underlays are made of two parts: crumb rubber and felt.
The upper side that comes in contact with the carpet is felt and the bottom half is crumb rubber.It combines the stability of the felt with the luxurious bounce of the crumb rubber.
Specialist use underlays
These are underlays specially created to be used with underfloor heating, in moist conditions or in extremely high traffic areas.