BENEFITS OF CARPET CUSHION
According to the Carpet Cushion Council, separate carpet cushion offers the following advantages to carpet installations:

Carpet cushion can add a useful life to a carpet
A common misconception made about cushion is that you can save money by increasing the pile weight of a carpet and eliminating the cushion. Actually, a cushion may result in more useful life in some carpet applications than slightly heavier unprotected carpet can offer.

Carpet is seldom replaced because it "wears" out. It is usually changed because it "uglies" out—or loses its fresh, new appearance. By reducing pile height loss and pile crushing, cushion can help keep a carpet “new” looking—and therefore stretch its usable life span.

A carpet installed over separate cushion can be more economical
Separate cushion can prove to be the most economical installation over a period of time.

In wear resistance tests done by Independent Textile Testing Service, a variety of cushion types added to the wear resistance of carpet.
And in a test to determine loss of pile height, which gives the appearance of wear, carpets without cushion showed a 19.3% loss in thickness. Carpets with cushion may suffer only 5-10% pile height loss. So an installation with cushion can be more economical since most carpets without any form of cushion may need to be replaced sooner. The fibers of a carpet installed without cushion can become compacted more easily, and the “new” look of the carpet may disappear more quickly

Carpet cushion makes a carpet seem richer and more luxurious
The most universally accepted benefits of carpet cushion are that it makes a carpet feel better and look better longer.
While the luxury is a subjective quality and cannot be measured, cushion does impart resiliency and resistance to pressure, which contribute to a carpet’s feeling on luxury.

In research conducted by Independent Textile Testing Service, a test was used whereby different carpet/cushion systems were subjected to rolling a chair with 150 lb. Weight over them 20,000 times. The results indicated that carpets with no cushion had an average of 19.3% loss in pile height (thickness) as opposed to a 5-10% loss in thickness for carpets with a separate cushion. The favorable effect of cushion in reducing the appearance of wear was indicated by decreased loss in thickness. So since carpets with separate cushion remain thicker, they could also appear more luxurious for a longer period of time. And with separate cushion, it’s possible to select the degree of luxury or firmness of tread you desire.

Carpet cushion can significantly improve a carpet's acoustical properties
A carpeted environment is quiet because the pile surface absorbs surface noise at the source. But a carpet installed with separate cushion can make the room even more quiet.

Tests conducted in the Kodaras Acoustical Laboratories reverberation chambers substantiate this. For example, in floor sound absorption tests, a carpet laid directly on concrete floor, with no cushion, measured a Noise Reduction Coefficient of 0.25. In a like test, the same carpet with a cushion on a concrete floor measured a Noise Reduction Coefficient of 0.65, a considerably better performance.
Separate cushion can also reduce impact noise transmission. On a concrete floor with no cushion, a carpet registered an impact noise rating of +14. The same carpet with separate cushion had an impact noise rating of +25—again significant improvement.

Carpet cushion can improve the thermal insulation properties of the floor covering
Another of the undisputed qualities of carpet cushion is that it improves the overall thermal insulation properties of a floor covering.
In fact, typical carpet cushions have been measured to have “R-values” from .75 to 2.0. R-values are commonly used to measure a material’s resistance to heat flow.

Carpet cushion can reduce the impact exerted on floor covering by one-half
Another factor related to luxury is the underfoot cushioning properties imparted by cushion properties imparted by carpet cushion.
In tests conducted at the University of Chicago, the effects of people actually walking over carpet and cushion were measured. The tests revealed that carpet by itself and cushion by itself have only limited impact absorption value. However, when the carpet and carpet cushion are combined into a proper system, the ability of the floor covering to absorb walking impact rises dramatically. And this can improve your comfort by reducing walking fatigue.

Maintenance costs are often lower during a cushioned carpet's life
Vacuum cleaning is more efficient with separate cushion since most machines “lift” the carpet to provide air circulation, thus insuring maximum cleaning power. This can help reduce the grinding action of embedded dirt that can cut and fray fiber.

Carpets with separate cushion can be less costly to install
At first glance, carpet installations without separate cushion seem less costly. But upon further examination, it can be argued that they represent a false economy.

First, direct glue down or attached cushion installation may be less expensive initially. But the difference could be made up in removing worn carpet in glue-down installation when labor costs for removal and clean up of the floor will most likely outweigh the original savings.
A carpet with separate carpet cushion will mask surface irregularities. A carpet alone cannot conceal crack and trowel marks as effectively as a carpet with cushion. This often means that less floor preparation is required before the carpet is installed.
In fact, a study of carpet workrooms (professional installers) indicated that when all installation factors are taken into consideration—floor preparation, carpet installation, carpet removal, and cleaning and repair of the floor after removal—the costs of a separate cushion are significantly reduced over that of a direct glue down installation.



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.

Foam
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.

Rubber
There are two basic types of sponge rubber carpet cushion:

Waffled rubber cushion is made by molding natural or synthetic rubber. Heat cures the rubber and forms a waffle pattern. This variety produces a soft, resilient cushion whose luxurious feel is particularly useful for residences.

Flat sponge rubber is a firm, dense cushion, which has a flat surface and is normally used in large-scale commercial applications and with loop type (or Berber) carpet.

Rubber cushion manufacturing processes can be varied to produce different levels of density and firmness. The usual measurement is the weight in ounces per square yard.

Fiber
Foam and rubber cushions are produced from new and recycled materials. Fiber cushion, on the other hand, uses existing fibers (both virgin and recycled, and either natural or man-made fibers), which are interlocked into a useful sheet of felt. There are two distinct varieties of fiber cushion:

Natural fibers include felt, animal hair, and jute (the material used to make some kinds of rope and heavy burlap bags). This is one of the oldest types of carpet cushion, dating back to the earliest days of machine-made carpet.

Synthetic fibers include nylon, polyester, polypropylene, and acrylics, which are needle-punched into relatively dense cushions which have a firm feel and, as with other types of cushion, can be made in virtually any weight, to stand up under light, medium, or heavy traffic, which is how they are usually classified.

Special Notes:
Berber carpet is becoming increasingly popular, and needs a thin, firm cushion. When using this type of carpet, be sure that the accompanying cushion has been specified by the manufacturer as suitable for Berber carpet.

Radiant heating is becoming more widely used in certain sections of the country. In the case of radiant heating, you do not want a cushion that is an exceptionally effective insulator, but one that allows the heat from the subflooring to penetrate the carpet system and heat the room. A relatively thin, flat cellular sponge rubber or synthetic fiber cushion works well under these circumstances. Be sure to ask your customers if their room(s) have radiant heating.


GLOSSARY OF TERMS:

Bonded Polyurethane – Cushion produced by grinding flexible polyurethane foam into small particles and binding them together with a chemical adhesive.Compression Force Deflection – Measurement of polyurethane cushions load-bearing characteristics. The result shows the reaction to loading applied over time such as when a person stands on it.Compression Resistance – Measurement of rubber cushion’s load-bearing characteristics. This indicates the product’s response to immediate loading such as that experienced when it is stepped upon.Densified Polyurethane – Flexible polyurethane foam cushion having modified, elongated cells.Flat Rubber – Natural or synthetic rubber cushion with a flat finished appearance on both sides.

Grafted Prime Polyurethane – Flexible polyurethane foam cushion formulated with added reinforcement for increased load-bearing.

Mechanically Frothed – Cushion of polyurethane chemicals and reinforcing filler frothed with air into the reacting mixture.

R Value – A measure of resistance to the flow of heat. Higher R values indicate a materials greater ability to insulate. click here for more information ...

Reinforced Froth – Open-celled rubber cushion reinforced with solid rubber particles (usually from recycled tires).

Resinated Recycled Textile Fiber – Needle-punched synthetic fibers recycled from textile processes.

Rippled Rubber – Natural or synthetic rubber cushion produced to give the appearance of bubbles on the surface and usually containing non-woven or paper scrim on the top side.

Rubberized Hair – Needle-punched felt of clean, sterilized natural fiber coated with skid-proof resin on top and bottom.

Rubberized Jute – Needle-punched felt of just fiber sealed on both sides with filled latex and embossed.

Synthetic Fibers – Non-woven needle-punched felt made principally of post industrial scrap synthetic carpet material with no outside additives.

Textured Rubber – Natural or synthetic rubber cushion produced with a fine textured appearance on the bottom and non-woven or paper backing on the top.