HISTORY OF CARPET CUSHION
In the early twentieth century, Americans placed carpet cushion beneath area rugs for added comfort underfoot and increased insulation. Eventually, carpet cushion use was expanded as homeowners took advantage of its inherent thermal qualities for increased insulation.
Some of the first carpet cushion was made from cattle hair, obtained as a by-product of the leather tanning process, because of its great resilience and durability. However, between the 1930s and 1950s, the tremendous growth of the tufted carpet industry caused an increase in carpet production, which exceeded the availability of cattle hair. Gradually, hair carpet cushion became a mixture of the jute plant because its qualities were similar to those of cattle hair. Today, this natural fiber underlay of hair and rubberized jute comprises about 2 percent of the current carpet cushion market.
Synthetic carpet cushion, also part of the fiber cushion family, is made by needlepunching off-grade carpet fibers. Although synthetic carpet cushion use has experienced rapid growth over the last three decades, it constitutes about 5 percent of the current carpet cushion market.
After World War II -- to meet the burgeoning demand for tufted carpet -- sponge rubber carpet cushion emerged. Made from natural rubber or styrene and butadiene rubber developed by tire companies during the war, sponge rubber is, by definition, an elastic porous mass with interconnecting cells obtained by combining rubber with blowing agents under heat-intense conditions. This gives the cushion its sponge-like effect. Today, three plants in the United States manufacture sponge rubber carpet cushion, totaling about 4 percent of the carpet cushion market.
The remainder of today’s carpet cushion business in the United States belongs to polyurethane foam -- both prime and bonded -- mainly because of its versatility, permitting it to be used in the manufacture of prime, graft, densified, bonded, and mechanically frothed carpet cushion. Each year, around 700 million pounds of polyurethane foam trim is gathered from all over the world from the manufacture of such items as sofas, chairs, mattresses, automotive interiors (i.e. door panels, seat cushions, etc.), textiles and clothing. This polyurethane foam trim is compressed, baled and transported to approximately 30 U.S. factories where it is recycled into bonded carpet cushion, making it one of the largest uses of recycled materials in the world.
A common misconception made about cushion is that you can save money by increasing the pile weight of a caret 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.
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.
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.
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.
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.
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.
Carpet cushion makes carpet easier to maintain
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.
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.
The following article was taken directly from the Carpet Cushion Council. (www.carpetcushion.org). Also, please visit my websites at www.americarpetfloors.com and www.stylishrugs.com for all your flooring needs.