The look and performance of a particular carpet is determined in large part by its construction, which may be loop, cut or combinations of the two.
Various types of high performance backing systems have additional advantages, including higher tuft binds, added stability, imperviousness to moisture and resistance to edge raveling. Consideration should be given to the functional needs of a particular area.
Understanding carpet construction assists in specifying elements that will provide the best performance in a particular location.
Carpet can be made by-hand or by-machine. The manufacturing of handmade carpets dates back to ancient times and may be made with one of three techniques -- hand-knotted, hand-tufted, and flat-woven. Machine-made carpets can be manufactured by weaving, tufting, or needle-punching.
Hand-knotted rugs are made by-hand on a specialized loom. The process of making a hand-knotted rug is incredibly taxing, and requires the weaver to insert knots into the rug and tie them each by hand. Because of this careful construction, hand-knotted rugs will often last for hundreds of years compared to hand-tufted and machine made rugs. Hand-knotted rugs are considered a work of art; since they are not mass produced, each one is unique and a direct reflection of the weaver’s creative design. These rugs are often quite valuable and can be passed down from generation to generation—an heirloom quality that is rarely found in any form of product.
Hand-knotted rugs have a pile that varies according to the number of knots per square inch, type of material and method of knotting. Each weaver will tie an average of 60 to 150 knots per inch to make the rug and the design. The material of the pile (main body) of fine handmade rugs is usually wool, but occasionally wool and silk, or just silk; the foundation is normally cotton, but can also be silk, or wool in tribal or nomadic rugs. Hand-knotted rugs have no backing and are symmetrical on the front and back. The hand-knotting method requires the most time and has the greatest value within the handmade category.
A hand-tufted rug is not fully handmade; a worker uses a hand-held tufting gun to push yarn through the backing material while following a pattern printed on a canvas backing. These yarns are then held in place with another piece of fabric and glue.
Hand tufted rugs are made to look like they are knotted, with glue that is spread over the back of the rug to hold the tufts in place. Then a backing material is sewn on to hide the glued area. While hand-tufted rugs have a handmade look, they do not retain the pedigree of a hand-knotted rug. These rugs are considerably less expensive than hand knotted; for example, hand-tufted area rugs may take about 1 day to produce, whereas a hand-knotted area rug may take 6-9 months. Be prepared to treat hand-tufted rugs gently; they are difficult to repair and cleaning requires more than wiping with a mild soap and water.
Hand-woven rugs are made by woven threads on a loom; they are called flat weaves because unlike knotted or tufted carpet; they don’t have a pile. Flat weaves work well as an accent rug under a table or as a hanging tapestry. The tightness of the weave determines a flatweave rug’s value. Individual threads are interwoven with the warp as vertical threads that are the foundation, and the weft, horizontal weave that makes the design.
Native American rugs are always flat weaves; usually hand woven with wool. Rugs from Pakistan, Iran, India and Morocco are hand woven with intricate designs made by different colors and thicknesses of the weft strands; these imported rugs are called Dhurries, Kilims or Gilims, or Soumaks. Most flat-woven rugs have the advantage of being reversible, which helps with the wear in high traffic areas; although Soumaks are usually not reversible. A rug pad is necessary with flatweave rugs simply because they are lighter weight than a pile rug and slip easily.
While it’s true that machine-made rugs rarely match the quality of handmade rugs, advances in technology have gotten to the point where high-quality machine-made rugs are produced at fractions of the price of handmade rugs. Today around 95 percent of all commercial carpets on the market are tufted, mainly due to the fast production time, lower price point and high design flexibility of this type of construction. Tufted carpet also offers a broad range of pattern possibilities, using pre or post-dyed yarns, varying loop height and cut or uncut pile.
When choosing between tufted or woven carpet, installation is an important consideration. A woven carpet is essentially stitched together along the side, while a tufted carpet can be easily seamed both along the sides and across the ends. This means that less carpet is required for a tufted carpet installation, the process is usually speedier, requires less skill and is less prone to errors. Tufted carpet will produce great results in most applications, however there are times when the generally superior quality and durability of a woven carpet may be preferable.
Machine weaving was the main means of carpet manufacturing up until the 1950s, when advances in machinery and the introduction of synthetic materials began the era of tufted carpets. Today, most carpet suppliers still carry woven carpets as an option due to their exceptional quality and durability. This is especially true of woven carpets using natural materials such as wool or wool blends, although the quality and purity of the wool are key factors impacting the long-term appearance and durability of the carpet.
Woven carpet is created on looms by simultaneously interlacing face yarns and backing yarns into a complete product, thereby eliminating the need for a secondary backing. A small amount of latex-back coating is usually applied for bulk. The plush appearance of woven carpets make them ideal for high-end projects where a luxury look and feel is required. Principal variations of machine-woven carpet include Wilton and Axminster.
While printed rugs feature a low-pile, they are supremely soft underfoot. Printed carpet is any carpet that achieves high definition patterns and graphics using state-of-the-art manufacturing techniques that print directly on unfinished carpet. Their easy-care nature and durability make them ideal for high traffic areas. Printed rugs may often be refreshed seasonally, thanks to their affordability.
Needle punched carpet is extremely colorfast, dries quickly and is very resistant to sunlight and fading. However this process doesn't offer much design versatility. Needle punched carpet is not recommended for general use, but is an excellent choice for areas where moisture could be a problem, such as pool decks, locker rooms and patios. Needle punched carpet is most commonly used for entry mats and is available in both broadloom and carpet tiles.
The two main types of carpet construction are defined by the way the carpet fibers are attached to their backing; the two main categories are loop-pile and cut-pile. A combination of the two is called cut-and-loop. The final grouping is woven carpets, which do not have a backing at all.
Loop carpet features short loops that stand up well in high-traffic areas -- like hallways, stairs, and basements. They are relatively lower cost, and because of the looped construction, spills tend to sit on the surface of the carpet so if you can get to them early, you will likely be able to prevent them from sinking into the fiber.
Loop pile is also trackless, so no vacuum or footprints will show. Unfortunately, the fibers can get snagged and pulled loose by sharp objects and pets’ claws. While this doesn’t affect its lifespan, it can make a loop pile carpet look disheveled over time.
Loops are all at the same height.
Loops are designed at different heights and can be arranged in geometric patterns, giving the carpet a 3D texture.
A "tip shear" carpet has both looped and cut-pile fibers, which creates height and texture patterns in the carpet. The different fiber cuts can all be the same length (level cut-and-loop), or they can be at different heights (textured cut-and-loop).
In recent years, the term 'berber' has become mistakenly synonymous with the entire level loop category. Berbers are actually a specific type of loop-pile carpet traditionally made of high-quality wool and are multi-colored or have the traditional color fleck, which makes them great for hiding dirt and any stains that do occur. They are extremely durable and are inspired by the weaving style of the Berber people of North Africa.
Cut pile carpets are made my cutting the yarn tips so there aren’t any loops. Cut pile carpets come in a wide variety of different lengths, thicknesses, colors and are typically made out of polyester and wool. Cut pile also contains a twist which helps it stand up and resist matting and crushing, which is one of its advantages. Another advantage is that they’re softer underfoot than loop carpet, making it a great choice to use for most of your home. However, cut pile can be more difficult to clean and maintain since the loose fibers allow dirt and liquids to spread into the carpet.
Plush cut-pile carpet, sometimes known as "velvet", has a very even, smooth with a more formal appearance.
Saxony tends to come to mind for most people when they think of carpet; it’s the most traditional cut-pile carpet, with fibers standing straight up and cut into even lengths. It has a smooth and luxurious looking finish, similar to plush pile but with a higher pile height and a little more twist in the yarn.
Textured saxony carpets have a luxurious feel with a more textured finish. The pile is highly twisted and lies in different directions so it hides footprints well and is great for higher-traffic areas.
Frieze carpet is a very popular style of carpet, characterized by long fibers with a high twist. The twisting is so tight that the fibers actually begin to curl back upon themselves, making for a very dense texture that performs well under heavy traffic.
Shag, also called Cable, is a deep-pile carpet type with long shaggy fibers. It's extremely comfortable underfoot and hides seams well, but doesn't stand up to high-traffic.
All carpet has some type of backing system or chemistry that helps keep the tufts in place. Backing systems are made from a variety of materials and may also come with various kinds of protective treatments (such as anti-microbial or anti-stain) or beneficial properties (such as anti-static).
The methods and chemicals used depend upon the performance requirements of the backing and the carpet. These decisions will be based upon the specifier’s performance considerations and the manufacturer’s recommendations. Performance considerations are especially important for demanding environments. It’s important that the specifier identify the highest priority needs for how the carpet will perform, whether that is wear and tear, moisture-resistance, or heavy foot traffic. The manufacturers’ end use recommendations help determine which product will meet the established performance expectations.
Carpet backing systems contain the following elements: a primary backing, a chemical adhesive, and often a secondary backing. In the most common system, the yarn is secured into the primary backing by synthetic latex, and a secondary backing (or cushion) is attached with a bonding agent or adhesive to provide further pile-yarn stability and to add dimensional stability to the carpet structure.
Whether a carpet has a secondary backing depends upon the end use of the carpet and the location of the installation. Carpet for high performance end use generally has a primary backing and a secondary backing or often an added cushion attached to the primary backing.