Carpet Construction: Common Elements

There's a variety of carpet construction processes, yet most tufted carpets have the following in common:

Face Yarn: The material on the top of the carpet, often referred to as the “pile.” This is the part to which we pay most attention and focus our cleaning efforts since the face pile directly influences how a carpet performs.

Primary Backing: This is a component of tufted carpet goods. It is a tightly woven (usually polypropylene or rarely jute) or non-woven (spun polypropylene only) fabric. During manufacturing, the pile yarn tufts are inserted through the primary backing by tufting needles (similar to a sewing machine).

Secondary Backing: This is the backing material visible on the back of the carpet. Commonly, secondary backings consist of an open woven fabric made of polypropylene strands. The secondary backing provides stiffness and a solid foundation to support the face yarn. It also provides the dimensional stability needed to assure that the carpet will stay in the same shape intended after it is installed.

Commercial carpeting also uses woven polypropylene backings; however, some commercial construction has the face yarn attached directly to an impervious sheet of plastic such as vinyl. When this type of carpet is produced in squares or carpet tiles, it is called “modular.” Carpet tiles can be made with a layer of fiberglass laminated with vinyl or a foam secondary backing. Commercial carpet with a heavy scrim coating applied to the primary backing produced in 12–15 ft. widths is called unitary backed carpet.

Latex Adhesive: The glue that bonds the carpet tufts to the primary backing and holds the primary and secondary backings together. Improper application or preparation of this latex during manufacturing is a leading cause of delamination, the separation of the primary and secondary backing. Delamination is most common in carpet constructed with a woven polypropylene secondary backing.

A variety of situations can cause delamination, including excessive pet damage, improper use of solvent spotting agents, excessive foot traffic, or the use of heavy rolling carts or wheelchairs. Delamination is rarely caused by normal cleaning procedures.

Adapted from The Complete Guide to Cleaning and Restoration (Burlington, WA: Legend Brands, 2017).