These underlays are designed for the carpet fitting trade, where two particular features are important - the need to be hard wearing and to be able to be stuck down to the floor.
Being firm and hard wearing is important because larger commercial projects often involve very large floor spaces where there will be lots of foot traffic - for instance, offices or restaurants. To stand up to the huge amount of wear and tear as thousands of people walk back and forth, the underlay must be very tough.
If the floor area is particularly large then it is possible for the carpet to move and stretch as people walk back and forth. The solution is to stick the carpet to the underlay (called ‘single-stick’), so the underlay surface needs to be able to be glued. In addition, the underlay is sometimes also stuck to the actual floor as well as the carpet, and this is called a ‘double-stick’ application.
Contract quality underlays are incredibly durable, and where a hard wearing underlay is needed they can be used in a domestic setting just as well as in a commercial setting.