Structure and Evaluation of Soft Floorcoverings

Delia Tacheny

INT 323 - Textiles, Materials, and Sourcing

Weekly Summary

The past few weeks we have been discussing the variety of soft floorcovering options. However, this week the reading covered more of the technical aspects of floorcoverings including the foundational cushioning and padding that goes under floorcoverings and the evaluations, testing, and specifications for floorcoverings in general. 

There are three categories of floorcovering cushioning: fibrous cushions; rubber and latex cushions; and polyurethane foam cushions. Hair (typically cattle hair) and Jute cushions are the most common natural fibrous cushion types. They are typically inexpensive; however, they both shift, bunch, and clump under heavy traffic conditions. They also tend to age, crumble, and disintegrate as well as being prone to moisture damage. For a variety of these reasons, a few additions are often recommended when using these natural fiber options: a loosely woven jute scrim woven to add stability, antimicrobial agents, or latex protective sheets in below-grade locations. Synthetic fibrous cushion options are more popular due to their stability, resiliency, and moisture resistance; fibers typically used are nylon, polyester, polypropylene, or acrylic. 

When it comes to rubber cushioning, waffled (rippled) sponge rubber tends to feel softer compared to the firmer flat sponge rubber cushions. Waffled sponge rubber has larger cells and thicker cell walls than flat sponge rubber; it is therefore more porous and less likely to retain odors. The rippled shape has a comfortable level of buoyancy and compressibility, but it lacks uniform support and could be more prone to crumbling. In contrast, flat sponge rubber cushions provide uniform support, and better skid resistance.

Polyurethane foam cushions come in a few different types: prime (in grafted or densified form), mechanically frothed, and bonded. Each is manufactured differently, but densified prime polyurethane cushions have a higher density and have many performance features due to the fact that the foam’s chemical structure is actually modified during the manufacturing process. The higher density is produced from finer, more elongated cellular structure and somewhat horizontal struts. One of its key features is being susceptible to bottoming out.

Compressibility, tensile strength, and elongation are the three most important performance features for evaluating carpet padding. Minimum compression loss implies that the cushion thickness is more resilient to compression and will recover easier; in its process of recovery, the pressure upwards on the cushioning will also recover the carpet. Tensile strength and elongation both pertain to the rupturing of the carpet padding. 

On the topic of evaluations and specifications, standard test methods and performance specs. help those in the industry with manufacturing and marketing efforts. The gathered data can be used to help industry members identify the need for changes in either composition, manufacturing, or conversion of their product; and it can be used to back up claims made in marketing efforts and promotional materials. Product performance data helps those buying and specifying the product such as interior designers and architects so they can specify the correct product for various end-use conditions. Pile construction density, pile height, and pile weight are variables that are specifically specified to ensure that a floorcovering will withstand the traffic conditions in the end-use location and conform to necessary design codes. All three factors influence wearability, resilience, and appearance retention. 

A major functional feature of carpeting is its impact on acoustics including sound absorption and transmission. Cut pile textures tend to be more absorbent than loop pile textures, and increasing the weight or height of the pile layer will increase its sound absorption capabilities. Additionally, more permeable structures will absorb sound more efficiently. When it comes to cushions for example, hair/jute cushions are more effective acoustically than less permeable sponge rubber cushions of a similar weight; attached cushions are less permeable and therefore less effective. This principle is also why carpet absorbs sound better than hard/resilient flooring which has very low permeability. Better sound absorption can reduce the level of noise throughout a space; however, it has a negative effect when it comes to noise transmission: the more permeable the structure, the more likely noise will be transmitted to spaces below.

The insulative value and effects on indoor air quality (IAQ) are other factors of consideration. A "K-value/factor" numerically represents the rate of heat transmittance, and the "R-value/factor" numerically represents the resistance to heat flow. The type of a material tends to impact the K-value, while the thickness of a material influences the R-value. Textile fibers have a very low K-value which means they are poor conductors of heat, but they can contribute insulative value. When considering IAQ, it’s important to look for carpet, cushioning, and adhesive materials that have low VOCs.

A variety of tests are done to evaluate the multitude of performance features. Other properties of evaluation include colorfastness, microbe resistance, flammability, static generation, and wear resistance. 

Yates, M., & Concra, A. (2019). Textiles for residential and commercial interiors / Mary Paul Yates ; Adrienne Concra. Fairchild Books, Bloomsbury Publishing Inc.

Research Initiatives: Carpet Padding

To dive a little deeper into carpet padding, I researched a few different types that weren't specifically mentioned above including rebond, horsehair pads, and felt pads. I've included pictures of each type to serve as a visual aid. 

Rebond is made of 100% recyclable foam, and has a multi-colored appearance to prove it. Rebond is one of the most popular options with affordable pricing and a wide range of densities and thicknesses. It is eco-friendly and highly durable. However, for heavy amounts of foot traffic such as in commercial spaces, a slightly more durable option may be better (Haas).

Horsehair padding can be used for carpets or furniture. McLaughlin 1889 uses natural horsehair in their custom furniture. They say on their website that since horsehair curls, it is an ideal natural option. It has great resiliency and is longer lasting than many synthetic options. (McLaughlin 1889).

Felt padding is another great option for carpets. According to my research, felt is very dense and compressed; it offers excellent durability and resiliency, and it is resistant to mold and mildew (so it is a good choice for more humid spaces.) Apparently, it is also naturally fire-resistant and provides great sound insulation and shock absorbency (Wade).

Haas, K. (2018, November 16). Carpet Padding Guide: Everything You Need To Know. Flooring Inc. https://www.flooringinc.com/blog/carpet-padding-buying-guide/

Padding. McLaughlin 1889. (n.d.). https://www.mclaughlinupholstering.com/portfolio/padding/

Wade, O. (2023, February 3). Is felt a good carpet padding?. Remodel Or Move. https://www.remodelormove.com/is-felt-a-good-carpet-padding/#:~:text=Yes%2C%20felt%20is%20a%20good%20type%20of%20carpet,with%20high%20humidity%2C%20such%20as%20bathrooms%20and%20basements.