When touting their eco-friendly ceramic tile, manufacturers often bring up percentages of recycled content. Certainly, incorporating material otherwise destined for a landfill is nothing to scoff at. But recent advances in manufacturing, technology, and even printing have made sustainability more than just a numbers game.

At its most basic, ceramic tile is an inert product formed of varying amounts of clay, aggregate (usually silicate sand), and feldspar. It is fired at temperatures ranging from approximately 1,400 F to 2,200 F, effectively killing any organic components and eliminating the possibility of off-gassing. In fact, says Ryan Fasan, senior partner at tile consulting firm Professional Attention to Tile Installations (PATTI), an April 2010 addendum to LEED credit IEQ 4.3 exempts ceramic tile from the third-party testing requirement for VOCs.

Ceramic tile is durable and requires little in the way of upkeep. But its longevity depends, in part, on whether the right tile is used for a given application. ANSI 137.1 classifies ceramic tile into four types based on water-absorption potential; the lower the water absorption level, the denser the tile. Wall, or nonvitreous, tiles can absorb more than 7 percent of their weight, while semi-vitreous tiles, which are acceptable for residential flooring, absorb water at a rate between 3 percent and 7 percent. Meanwhile, vitreous products are limited to an absorption rate between 0.5 percent and 3 percent, and can be used in exterior applications as well as in interior wet rooms such as entries and bathrooms.

Finally, there’s porcelain. Although it does not appear in the ANSI standard, porcelain has a specific definition in the tile world, says Bill Griese, standards development and green initiative manager of the Tile Council of North America. “It’s any ceramic material with a water absorption level of 0.5 percent or less.” Its high density is ideal for floors subject to wheeled traffic or in submerged areas. Most porcelain tiles are made from kaolinite-rich clays that can tolerate the high firing temperature—above 2,000 F—necessary to ensure strength and imperviousness.

Manufacturing practices for ceramic tile today often use renewable energy sources, produce less greenhouse gas emissions, and recycle packaging materials. Perhaps more importantly, the industry as a whole has moved toward closed-loop production, which recovers and reintroduces factory waste into the tile-making process, thereby “fully utilizing all resource inputs and virtually reducing waste output from the factory to zero,” Griese says. Typically, raw ceramic material is filtered and recaptured from the water, allowing both to be reused to manufacture new tile. Fired waste is ground up to serve as building or road aggregate.

However, Crossville, Tenn.–based tile manufacturer Crossville Inc. has developed a system for processing and reincorporating fired waste into its products, diverting some 4.5 million pounds from landfills annually. Tim Bolby, executive technical services director, says there are both environmental and financial benefits. “Our accountants look upon production waste not as a cost anymore, but as a raw material, which is a complete turnaround in the business model,” he says.

The shift in thinking, Fasan notes, has long been understood by European tile fabricators, who closed the loop on operations decades ago—or found a friend to help them do so. In Spain and Italy, large tile producers recycle their own waste as well as that of smaller manufacturers for whom the process may not be as cost effective. This symbiotic relationship provides the latter with additional revenue while yielding the former a product with a high percentage of recycled content, qualifying them for credits under sustainability programs, Fasan says.

Tile manufacturers have also taken waste from other industries. Recycled glass, sourced from everything from containers to windshields and windows, is a popular partial substitute for feldspar, silicate sand, and the frit component in glaze, Fasan says. The glass must be clear to preserve color purity and consistency.

Crossville, meanwhile, has found a generous supplier of pure white, pre-consumer recycled material ideal for use in porcelain production: Toto. The plumbing fixture company delivers 12 million pounds of defective toilets to Crossville annually. “It has the perfect complexion,” Bolby says. “It allows us to maintain color in our body with consistency and achieve a higher recycled content.” Because of this partnership, Crossville now consumes more waste than it produces.

The company is not alone in seeing opportunities in plumbing fixtures. Fireclay Tile has become an indirect beneficiary of California’s strict water laws, grinding up old toilets that have been ripped from buildings and converted to low-flow models. It receives them for free from companies that would otherwise have to pay $8 to $10 a piece for disposal, says Paul Burns, Fireclay founder and chief ceramicist. The toilets account for 35 percent of the company’s Debris series tile body. Natural clay comprises another 30 percent, and the balance comes from glass dust from a recycler and Fireclay’s own glass tile factory, as well as granite dust collected from a rock quarry.

Seventy percent recycled content may sound high, but it all contributes to a better and stronger tile. “We don’t use recycled product just because it’s recycled,” Burns says. “It has to help the quality of the tile.” In fact, many industry experts caution against getting too hung up on percentages. “With ceramics, you don’t want to introduce too much recycled content because you could jeopardize the integrity and strength of the product,” Griese says. Increasing the amount of recycled content without compromising product performance requires investment in research and development that not all companies will make.

Such is the approach of Green Squared, a multi-attribute certification program based on ANSI A138.1 that the Tile Council of North America launched last year. Although only products can receive the Green Squared stamp of approval, the domestic and international companies seeking the qualification must comply with a variety of criteria that promote environmental stewardship and social responsibility as well as those that relate to material extraction, production, and end of life. To ensure credibility, certification is strictly third-party, performed by three authorized organizations: UL, SCS, and NSF International.

The program recognizes not only ceramic and glass tile but also dry powder, panel, sheet and liquid, and paste installation materials. Certified products qualify for points in the latest edition of the NAHB National Green Building Standard, or ICC-700, and discussions on potential LEED inclusion are ongoing.

Of course, no tile discussion would be complete without mentioning the improvements in and proliferation of digital printing. Multiple inkjet machines are not uncommon in factories and have expanded from the four traditional CMYK inkheads to six. Fasan says, “The resolution and saturation of colors are better than they’ve ever been,” resulting in wood and stone patterns that are vividly realistic. Beyond aesthetics, sustainability implications exist too. Instead of countertops made from “2-billion-year-old stone that has to be quarried, they can scan 4 square meters of a slab and print as much of it as they want,” Fasan says.

Other innovations in ceramic tile improve indoor and outdoor air quality, reduce the need for cleaning agents, or simplify installation. Tiles coated with titanium oxide neutralize VOCs and other air pollutants and self-clean when illuminated by natural or electric light. Large-format, slim-profile tiles can install over existing tile, “saving material from going to a landfill and saving raw materials coming back into the space,” Fasan says. And raised-access flooring and indoor wall systems that use mechanical fasteners instead of mortar allow access to infrastructure without damaging the tile finish.

The emergence of new manufacturing technologies and the growing number of products receiving third-party certification will likely be accompanied by a broader understanding of ceramic tile as a sustainable material. After all, sustainability is “not just about a single purpose of recycling and a percentage content,” Bolby says. “It’s about a process.”