TYPES OF CARPET CUSHION

There are three basic types of cushion:

    * foam (short for "polyurethane foam")

    * rubber (short for "sponge rubber")

    * fiber (short for "felted fiber")

Each type is further subdivided into two or three varieties. Each variety has characteristics that make it useful in particular types of carpet installation. Each variety also has grades, which vary by weight (also called density), thickness, and the amount of force it takes to compress the cushion.

Density is one of the most important parameters of any type of cushion. Density equals weight divided by thickness, and it measured in pounds per cubic foot. All types of cushion can be made dense (more material), or light (more air), or any grade in between, so they can be soft or firm, resilient or supportive, according to the type of room and expected traffic on the carpet they support.