Construction of Carpets and Rugs

The three most common types of carpet construction techniques used are tufted, needle-punched, and woven. Carpet construction also includes the way the yarn is put together and what is applied to the back of the carpet.

Ninety percent of the carpet constructed today is tufted. Tufted means that hundreds of yarn-threaded needles go through the back of the primary backing fabric to form loops or tufts on the front side. The loops are either cut or left in loops. Then the secondary backing is glued to the primary backing to hold the yarns in place and make the carpet stable so it will not stretch out of shape.

The second most common type of carpet construction is called needle punched. Needle punched construction consists of layers of carpet fibers layed onto a fiber mesh, then thousands of needles are punched through the fiber layers to produce a thick, felt-like carpet. The back is coated with a latex material. This type of carpet is very durable in high traffic areas such as kitchens or hallways.

Another type of carpet construction found on the market is woven. Woven carpets are made by weaving a surface yarn and backing material into a carpet. It is easy to identify because the carpet rolls only in the direction that it is woven. Woven carpets are uncommon today because of the higher cost due to slower construction.

Carpet construction also includes the yarn and how it is constructed. Yarn twist is important in determining quality carpet. Yarn twist affects a carpet’s appearance, durability, and resistance to matting. If the yarn is tightly twisted and heat set, the carpet resists matting and is more durable than the loosely twisted yarn.

Generally, tightly twisted yarns are denser than loosely twisted yarns because when the yarn is tightly twisted, the diameter gets smaller, which necessitates using more yarns per square inch. The yarn twist must stay twisted to be effective. If the yarn twist unravels, the carpet loses some of its ability to resist matting. Heat setting makes the yarn less likely to unravel.

Another important part of carpet construction is the back of the carpet. Carpet backing consists of two layers, a primary and secondary backing. The primary backing is found just under the carpet yarns. Some manufacturers color the primary backing the same as the surface yarns so that the carpet looks denser. The yarns should be firmly attached to the primary backing.

The secondary backing is generally made out of polypropylene, jute, sponge rubber, urethane, or foam, and glued to the primary backing. One disadvantage of jute is that it mildews if damp for a period of time, therefore, carpet with a jute backing should never be put on a concrete floor.

Polypropylene (olefin fiber) provides an excellent secondary backing because it is unaffected by moisture, resists mildew growth, and is strong and durable. The secondary backing can also be made out of sponge rubber or urethane. On some carpets, like kitchen carpets, the padding is attached to the back of the carpet. Some of these padding fibers are the same materials used to make the separate carpet pads.