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.
Generally speaking, foam cushion comes in three recognized, clearly different varieties:
Prime polyurethane foam is a firmer version of the same cushioning used in upholstered furniture, mattresses, and automobile seats. Two liquid ingredients are combined to form a large mass of foam, which is then sliced into sheets for use as carpet cushion.
Bonded polyurethane foam (sometimes called rebond) is quite unique. You cannot mistake it when you see it, because it is formed by combining chopped and shredded pieces of foam, in different sizes and usually different colors, into one solid piece. It frequently has a surface net for ease of installation and improved performance.Bonded foam is one of the most amazing recycling projects of all time. Nearly all the scrap foam in the U.S., and some from other countries as well, is utilized to make bonded cushion. This recycles waste, which would otherwise be thrown out, and it eases the strain on our landfills. Moreover, bonded foam is itself recyclable.
Froth polyurethane foam is made with carpet backing machinery. Liquid ingredients are applied, either directly to the backs of some carpet styles, or to a non-woven material (for making separate cushion). They react and form a thin, dense foam which is particularly useful in commercial applications with wide expanses of carpet.