Technology Transforms Tile  

Ceramic tile has been prized over countless generations for its beauty and utility, in buildings from modest houses to spectacular palaces and cathedrals. Recent advances in manufacturing technology are making the current generation of tile the most remarkable yet.

This course will give architects and designers the information they need to take full advantage of a wide range of new options in size, thickness, weight, surface, and function. Ultra-thin porcelain tiles are engineered to have the structural strength and resilience of heavier conventional tile, yet are so thin that they can dramatically reduce costs and expand design possibilities, not only in traditional uses like walls and countertops but also in new uses, such as laminates over existing tiles in renovation, veneers on furniture and cabinetry, worktops with integral induction heating elements, surfaces for ceilings that can dampen sound, innovative new building facades, and many others.

Thicker porcelain slabs and pavers are structurally strong and stress resistant enough for use in exterior structures, such as terraces, plazas, and rooftop decks, and in seamless transitions between indoor and outdoor spaces. In exterior hardscapes, the thicker tiles can be set like any other paver in sand, grass, or gravel, requiring no mortar, or supported by adjustable pedestal systems for raised access flooring. Yet they are light enough to transport in a service elevator, weighing significantly less than traditional exterior materials like marble and granite. They are also easier to cut and handle.

As the performance boundaries of ceramic tile are being pushed by technology, the aesthetic options are expanding too. New digital decoration techniques and digitally applied 3-D effects mean that tile surfaces can reproduce the precise look and even feel of other materials, including not only stone or wood but also steel, concrete, textiles, and fusion surfaces that have just been invented. Beyond skin deep, advanced mineral additives can produce tile that destroys contaminants, improves slip-resistance, and cleans itself.

The following sections will demonstrate how the inherent physical characteristics of ceramic tile relate to performance, and how advanced technology is taking those characteristics to new levels, with a particular focus on the benefits and applications of new gauged porcelain tiles, including current specifications and standards.

PERFORMANCE CHARACTERISTICS OF CERAMIC TILE

Different tiles have different properties, based on their exact composition, firing temperatures, and manufacturing processes. Some of the advanced gauged porcelain tiles discussed in this course have exceptional hardness and other advantages. But even the newest technologies are an evolution of the remarkable inherent characteristics of all ceramic tile.

Tile is composed of 100 percent natural minerals and materials, primarily clay, silicates, and feldspar. The extremely high firing temperatures required to fuse or “sinter” these materials into a ceramic body preclude the use of any chemicals or organic-based compounds. Even the new performance additives discussed here are mineral, not chemical. This inert composition and unique firing process are the basis of tile’s performance in a number of key areas.

Resilience and Durability

Mechanically, tile is one of the strongest, most durable and resilient finishing materials, both in interior and exterior applications. In the environmental product declaration (EPD) product category rules (PCRs) for flooring materials, products must document their environmental impact starting from production at source and including a multiplicative factor to account for replacement frequency through a 50-year timeframe, the average lifespan of a building. Ceramic tile is one of the few materials requiring no multiplier since its useful lifespan far outlasts most of the buildings where it is used. The ability of ceramic tile to last for many generations, surviving fire and flood, can be seen in numerous examples still in place after centuries. In one beautiful example, the Aljafaria Palace in southern Spain still has the original tile cladding on the balcony where Columbus knelt in 1492 to accept the commission that led to the discovery of the Americas.

More than 500 years later, fire and flood remain thoroughly modern challenges to building materials. Tile does not burn at any temperature, absorb smoke, or produce toxic fumes. It often does not need replacement even after a flood or fire. In fact, a tiled surface often protects the substrates and structures behind or beneath it in such disasters. Other materials not only need replacement, but adjacent areas often have to be replaced as well since spot repairs are not possible.

Unlike most other commonly used materials, tile is not affected by UV exposure. Colors in ceramic tile are permanent, not faded or changed by sun exposure. Spot repairs to tiled spaces can be done even decades after initial installation with little visible effect. Owing to this quality of the material, many artisanal ceramic companies exist today throughout Europe with a specialty in creating classic tile for heritage buildings. Gaudi’s beloved Parc Guell is among many historic buildings where areas of tile have been commissioned and replaced by such companies in the past few decades, with strict attention to compatibility, often capturing the same size and overall aesthetic but endeavoring to keep the original pure and distinct by intentionally leaving out some decorative components in the restoration materials.

Clean, Healthy Lifespan

Tile is one of the only finishing materials with zero volatile organic compounds (VOCs). Due to its inorganic and inert nature, tile is neither a primary or secondary source of VOCs. An addendum to LEED first added in 2010 states that tile is one of a small number of products that do not require VOC testing to contribute to points under Indoor Environmental Quality Credit 4.3.

Tile does not harbor bacterial contaminants or allergens. Tile surfaces—especially when glazed, which creates an impervious surface—can be entirely hypoallergenic. Glazes are largely composed of glass, thus the entire surface of glazed ceramic tile is nonporous. As discussed below, advanced antimicrobial components can now be added to tiles that destroy contaminants on contact for the life of the material.

Minimal Maintenance

Tile’s hard nonporous surface naturally resists stains and abrasion, and is easy to clean and maintain, normally requiring only water or steam, and occasionally pH-neutral cleansers. New photocatalytic technology based on a reaction between natural light and oxide catalysts encapsulated in the glaze is now being used to create self-cleaning tile that reacts with natural light and oxygen to repel dirt and make water runoff more easily. These advanced additives, discussed in more detail in the next section, are not coatings, are baked into glazes or into the body of the tile. They are also being used to improve slip resistance in both wet and dry areas.

Nonconductive, High Thermal Mass

Ceramic tile is an optimal material in new “smart” homes, since tile does not interfere with electrical infrastructures or harbor static charges that can cause electric shock. This characteristic also makes possible new applications such as induction cooktops built integrally into countertops. High thermal mass makes tile a highly efficient surface for HVAC performance. Ceramic tile acts as a natural cooling element in the summer and retains ambient heat in cold weather. With proper selection of color and placement in a high-performance structure, ceramics have immense potential in passive solar loss/gain performance strategies.

Life-Cycle Cost

Financial and environmental costs of tile over the lifespan of the investment have been extensively documented. Ceramic tile is composed of abundant natural resources, often sourced within a few hundred miles of the manufacturing facility. Its maintenance requirements over an exceptionally long service life are low and do not involve toxic chemicals at any point. The new thin porcelain tiles discussed in this course reduce the use of resources even further, as well as the cost and fuel used in transportation and handling throughout the supply chain.

A current example of the broad effort to increase and document tile’s environmental performance is the sector-wide study compiled by the Spanish tile manufacturers association, allowing companies to easily publish the type III environmental product declarations (EPDs) required by LEED v4 and other green building codes and systems. In contrast to what are considered “low-cost” materials, ceramic tile is low in all of the areas most important to long-term cost-effectiveness: replacement frequency, maintenance requirements, and environmental impact.

TECHNOLOGY AND TILE

The term “gauged” refers to tile that is precision engineered for a specific thickness and performance, using advanced production technology that has emerged only in the past few years. Gauged tile is often used as a blanket term for tile that is much thinner than ordinary tile, as slim as 3.5 millimeters (a little more than 1/8 inch) thick, with similar or greater structural strength. But gauge also applies to tile that is thicker (up to 30 millimeters, a little more than 1 inch), which is still relatively thin, and exceptionally light in comparison to traditional pavers of stone or cement. It is used in exterior applications such as landscapes and terraces, and for structural use such as cladding and facades.

For a wide range of projects, the recent availability of advanced gauged porcelain tile products represents a dramatic breakthrough, changing the entire cost profile, and generating imaginative new designs and products, such as the examples in this course. Because of its significant impact on the tile industry, gauged tile is discussed in detail in its own section below.

Two other technologies are major areas of technical and creative innovation in ceramic tile, and often utilized in gauged porcelain tile: new advanced additives, and cutting-edge digital design, decoration, and 3-D printing.

Advanced Additives

Advanced catalytic mineral oxides can now be encapsulated in the glaze layer of tile (or the body of the tile itself in the case of unglazed material), with multiple health, safety, and liveability benefits.

For example, these catalytic oxides react with light—sunlight or artificial, depending on the specific mineral oxide used as the catalyst—to destroy organic contaminants such as bacteria or mold upon contact with a tile’s surface and neutralize pollutants in the air.

Additives can also change the hydrophilic properties of the surface, creating greater surface tension and making water sheet off the surface, making cleaning easier or, in some cases, forming self-cleaning surfaces; for example on building exteriors, where dirt and grime can be consolidated for rain to wash off quickly and naturally.

Structural molds, nano-particulates, and molecular modifications can also create tile that is even more slip resistant when wet than when dry. These products can have smooth and even glossy surfaces, often called lapatto or semi-polished, in addition to the textured surfaces normally associated with slip resistance. These processes can produce safe and traffic-resistant tile flooring that remains comfortable on bare feet and easy to clean in almost any environment.

The additives and production techniques can be integrated into the design and texture of almost any tile. So, for example, continuous indoor-outdoor spaces can be created with no visual difference between natural finishes inside and nonslip finishes out.

Digital Design, Decoration, and 3-D Printing

Manufacturers are now able to replicate virtually any surface, finish, or texture, such as natural stone, corten steel, wood, metallics, even fabric, in a light, high-performing tile that retains all the functional advantages of traditional ceramics. Inventive new artisanal surfaces are also being created, some based on designs from historic sources, such as tapestries and antique tiles, as shown in the photo below, and mirrored surfaces created by a firm that has been producing actual mirrors since medieval times, as well as contemporary inventions such as etched reliefs with ink applied to crevices to create a unique crackled appearance.

Digital techniques are also used to produce very large-scale “infinite” graphics on large, visually seamless gauged porcelain slabs, both in interiors and exteriors, as shown in the photo below, which is one of a series of unique original artworks commissioned by a local company on 25 buildings throughout the city of Madrid. Custom graphics on tile are also being used in projects like NASA’s new museum at Cape Canaveral.

Beyond these aesthetic innovations, digital and nano-technology processes are also being used in the production of gauged tile and to incorporate the photocatalytics noted above, as well as for other evolving applications, such as integrating photo-luminescence and home automation into tile with touch-sensitive glazes, and creating tiles that are warm to the touch.

KEY CRITERION: GAUGE

Gauged porcelain is a specific term used in ANSI A137.3 and A108.19-2017 standards. (See Specification Basics section below for more information about tile specifications and standards.)

• Gauged porcelain tiles: less than 1 square meter
• Gauged porcelain tile panels/slabs: 1 square meter or larger

As used more generally, the term gauged tile refers to porcelain tiles (and other types of ceramic tiles, such as vitrified gres ceramics and non-vitreous wall tiles) that can now be produced in specific sizes, thicknesses, and performance characteristics, with more precision and variety than previously possible.

The thinnest tiles are around 3.5 millimeters (about 1/8 inch) and can be used for a wide range of applications, including walls, veneers, renovations over existing floors, and exterior cladding. The next range, from about 5–8 millimeters (still less than 1/3 inch), are often used in flooring. Slightly thicker gauges, from 12–30 millimeters (up to a little more than 1 inch), are used for applications such as some facades and new high-performance worktops. The gauge range for paving and other exterior structures is about 16–30 millimeters.

Gauged porcelain tiles can be selected from the same wide range of shapes and sizes as conventional tiles, but major new porcelain tile products include:

• Thin: Large-format thin porcelain panels—up to 1.5 meters x 4.5 meters (60–177 inches)—in various thin gauges.
• Thicker: 20 millimeters and 30 millimeters (up to a little more than 1 inch) ceramic pavers.
• Mechanically fastened (mortarless) installation options for uses such as ventilated facades, ceiling tiles, and pedestal raised-access flooring systems.

The manufacturing process for gauged tile involves the use of specialized clay materials, immense pressures at the press or “belt,” high temperatures with longer firing curves in the kilns, and precise computer-controlled timing throughout. In the most advanced plants, the entire production line is revamped for this type of production with a new style of belt press that exerts nearly 10 times the pressure of a traditional dry press.

Following the pressing is a new type of digital “greenware” cutting station where the material is trimmed before firing so that the waste material can be reintroduced to the production stream, reducing waste and making multiple modular sizes possible without changing the press. With innovations in machinery and digital optimization, a modern plant can be more agile, operate on tighter tolerances, and retain higher yields of first-choice material with minimal staffing for oversight.

For the specifier and end user, the availability of multiple gauges makes it possible to specify the “minimum effective dose” needed for any given area. The term describes using no more or less than necessary to achieve an ideal solution. The technical characteristics in modern tile have progressed to the point that impact resistance, modulus of rupture, and many other critical characteristics are actually improved despite the varied reductions in thickness.

“The optimization provided by today’s digital manufacturing processes brings so much benefit to the project stakeholders and eventual end users,” says Ryan Fasan, technical consultant for Tile of Spain. “By creating multiple gauges in the same collection, manufacturers are creating solutions for savvy specifiers to afford more tile in their projects and apply its benefits much farther afield than the traditional bathrooms and backsplashes.”

The following sections highlight some of the major advantages for both thin and thicker gauges in specific applications.

THIN-GAUGED PORCELAIN: LOSING WEIGHT WHERE IT COUNTS

At the very thin end of the spectrum (3.7–5 millimeters), thickness and weight are reduced as much as possible to meet or exceed mechanical requirements for specific environments. The reduction has a dramatic impact on the cost of tile in a project and the range of projects where tile can be effectively used.

In general, reducing the thickness of a tile by 1 millimeter (0.04 inch) equates to a reduction in weight of 10 percent. This is based on the 10-millimeter median thickness of traditional tile.

Ocean freight, inland trucking, rail, and duties are a large factor of landed cost (the total price of a product as it arrives at its ultimate destination). This freight cost accounts for approximately 30–45 percent of a tile’s cost to its end user in North America, depending on the port of origin and how delivery-to-door weight allowances are calculated.

The impact on landed cost from reduction in thickness of a tile product can be indicated in a simplified way as follows:

Landed cost equals (product cost per square foot) plus (delivery charges, inland trucking) plus (container cost) divided by (square footage per container by weight).

The freight cost component—which, as noted above, accounts for 30–45 percent of the product’s cost—is reduced by 10 percent per millimeter. The reduced thickness of the tile allows for more tile to be packed into each container.

The reduced weight lowers delivery charges during the initial phases of transportation, but the savings continue to compound throughout the project, as detailed below.

• Product lands at distributor, and markup is factored. Overhead (trucking to branches, marketing, etc.) is factored into the product cost prior to setting the sale price. Lower landed cost for the distributor means the standard markup percentages are applied to smaller numbers, translating to a lower cost for the consumer.
• Job packing and deliveries. Again, lower weight of the material means that the cost of contractors or private delivery companies is less per square foot of material as the product moves from the point of sale to the job site.
• On-site labor. The lighter-weight material often requires smaller crews to move material around site and fix to the surfaces, again lowering the overall cost. Gauged tile is also easier to cut and maneuver, and—with an experienced installation crew—can save installation cost and complexity.

There are other advantages of thin-gauged porcelain tile in addition to financial costs. For example, with very large-format thin slabs, there are fewer—and almost invisible—grout lines. This is an obvious advantage in residential kitchens and bathrooms, and the aesthetics can be spectacular in many types of spaces; for example, with the use of very large-scale digital graphics shown in the previous photo.

But the minimization of grout is highly functional as well; for example, in applications like restaurants and health-care facilities where grouts can collect grease or bacteria. In commercial bathrooms or other high-traffic areas that must be easy to clean frequently and quickly, thin low-grout porcelain can be applied directly over older, worn, or higher-maintenance tile floors.

Specifying the thinnest tile effective for the application also has a positive environmental impact, beginning with lower consumption of raw materials from the outset. For many state-of-the-art manufacturers already optimized for producing gauged tile, equipment and procedures are also in place to achieve substantial energy savings. After manufacturing, the ability to load significantly more of the thinner, lighter tile into containers and trucks not only reduces financial cost but also emissions of CO₂ and pollutant substances.

The light weight and enhanced performance properties of the thinnest-gauged porcelain tile are opening up creative possibilities in traditional interior applications and decidedly nontraditional applications, as outlined in the following sections.

Renovation

The use of gauged porcelain tile is growing rapidly in renovation. At a little more than 1/8 inch thick, new thin-gauged tiles are conceptually a solid-surface ceramic laminate. They can be installed directly over a sound and prepared existing tile installation. For floors, the old ceramic tile acts as a solid substrate, and the slim tile is mortared over it. Using slim-gauged tile in this way saves time and cost and eliminates waste to be hauled away to the landfill.

The durability of the new tile means that the renovation cycle, typically around six to eight years for public spaces, can be extended to many decades. In applications such as hotels and health-care facilities, this also significantly reduces costly time and disruption required for each refurbishing,

High-Performance Veneer for Worktops, Cabinetry, and Furniture

An example of utilizing the physical characteristics of porcelain tile in new ways, porcelain tiles in slightly thicker profiles, in the range of 12–30 millimeters (around ½-1 inch), are being used to create performance worktop and countertop surfaces. Using advanced digital decoration techniques, the surfaces can be specified with the look and feel of almost any material. In one pioneering system, full through-body decoration allows edges to be profiled like any other solid surface material, and the veining structures are homogeneous throughout the material. Another inventive application brought together tile manufacturer and induction-range manufacturer to laminate an induction cooking surface inside the slab. Tile’s hardness, high thermal mass, and low conductivity make it the only material physically suited to this type of system. These and other similar designs mean that cooks can prep, cut, cook, and eat on the same seamless kitchen surface, which can then immediately be used as a dining table or, as in the photo below, a desk or worktable.

Acoustical Ceilings

Traditional drop ceilings used in corporate and other commercial spaces are often afterthoughts at best, with specifiers left selecting the least-offending option rather than something that could be a positive design feature. Utilizing gauged porcelain tile can offer unlimited design possibilities, but the tile can also be a component of an acoustical drop ceiling with high R-value and near-zero flame-spread ratings. Some manufacturers are now specializing in this niche by adding sound-dampening backings and surface textures in formats that can be integrated into common track systems for suspended ceilings. The ceramic tiles provide an exceptional aesthetic, thermal, and acoustic option.

Ventilated Facades

Curtain-wall or rainscreen applications of ceramic tile panels installed on exterior walls with metal railing systems are highly energy-efficient and weather-resistant forms of exterior cladding. A physical separation is created between the outside of the facade and the structural wall of the building, allowing exchange of air. The facade material is advanced gauged porcelain tile, usually ranging from 3.7–12 millimeters (about 1/8 to ½ inch) depending on the fastening system and dynamic load tolerances of the structure.

These innovative thin, light facades can be engineered to optimize for reducing passive heat loss or gain depending on surrounding climate and building needs by adjusting the depth of the air chamber between the structural walls and the facade. Energy usage for HVAC systems can be reduced by up to 30 percent solely by incorporating one of these systems.

See the Forward Facades sidebar for more information about two exceptional examples of gauged porcelain tiles used in exterior cladding, such as the Laan van Spartaan student residences in West Amsterdam, which utilized gauged porcelain sheets 3 millimeters and 5 millimeters thick, in panels up to 1,000 by 3,000 millimeters, as in the photo below.

THICKER-GAUGED PORCELAIN: STRUCTURAL TILE

Many new products are also being developed at the thicker end of the gauged porcelain tile spectrum. Load-bearing porcelain pavers 20 millimeters (2 centimeters, around ³⁄₄ inch) and greater can be used for a wide variety of interiors as well as exterior structural paving, such as roof decks, plazas, and pool decks.

Paver tiles are typically available in 24-by-24-inch, 16-by-32-inch, and 24-by-48-inch formats, with some cut down to 12- or 8-inch planks as well, and they offer significant advantages over conventional materials. As with the very thin-gauged porcelain tiles, the thicker products are an evolution of the physical characteristics of ceramic tile, optimizing the weight and increasing the number of versatile formats while enhancing durability, resilience, and structural strength for a group of specific intended-use cases.

Pavers Indoors and Out

Porcelain pavers are load-bearing but much lighter than competitive materials of the same size, often requiring less labor and time to transport, handle, and install. For example, in high-rise applications, porcelain pavers can easily be brought up in service elevators. Tile is also generally easier to cut precisely with minimal breakage.

In both interior and exterior applications, its nonporous surface requires low maintenance, is slip resistant where necessary, and extremely resistant to external abrasion or scratching by hard tools, equipment, and foot traffic. Many porcelain pavers can give the visual illusion of heavy stone with a fraction of the weight.

As an example, granite pavers are generally 2 inches thick, with technical characteristics comparable to a porcelain paver of 0.75 inches thick. The granite pavers have an average weight of 22.5 pounds per square feet, while their porcelain counterpart averages less than half that, at just 9 pounds per square feet.

Many contemporary tile collections are now supplied in multiple gauges, making it possible to specify a thin-mortared tile for interiors and then a seamless transition to visually identical 20- and 30-millimeter pavers for the exterior hardscape.

As mentioned earlier, the thicker material does not need to be mortared in place and can instead be set like any other paver in sand, grass, or gravel and can even be supported by adjustable pedestal systems for raised access flooring.

Pedestal systems for less than 20-millimeter gauged pavers allow for a myriad of dry installation styles in different environments. Similar to the leveling pedestals used in cabinetry and millwork, the system can completely negate the need for expensive prep work prior to tiling. For interiors, the system allows for raised access flooring design, granting access to a plenum cavity for digital infrastructure and HVAC systems. In exteriors, it allows for premium waterproofing solutions to which traditional mortars cannot bond, and keeps all slopes and drainage from marring the surface of the installation.

Ceramic tile is closely associated with residential applications, but the strength and lightness of gauged tile, as well as new nonslip, highly durable surfaces, are the foundation of new products that meet the performance requirements of high-traffic areas, such as schools, airports, and hospitality, and of areas requiring exceptional hygiene, indoor air quality, and minimal maintenance, such as health-care facilities.

Open plans with cohesive flooring that runs through the entire space are a strong current design trend, not only in residential interiors such as master bedroom/bathroom suites and great rooms/kitchens with adjoining halls, but also in commercial spaces such as offices, flex-spaces, retail, hospitality, and large entertainment spaces, with consistent performance-based flooring selected throughout. Extensive options for color, texture, and graphics with virtually invisible grout lines provide maximum design flexibility in large, high-traffic interiors.

TILE SPECIFICATION BASICS

Standards and Specifications

American National Standard Institute (ANSI) standard specifications have been adopted for ceramic and glass tiles, and for installation materials such as mortars adhesives and grouts, including:

• ANSI A137.1:2017: Standard Specifications for Ceramic Tile
• ANSI A108/A118/A136.1:2017: Specifications for the Installation of Ceramic Tile
• ANSI A137.2:2013: Standard Specifications for Glass Tile

The ANSI American National Standard Specifications now in use and applicable to specifying the gauged porcelain tile discussed in this course were first adopted in 2016 are:

• ANSI 137.3/A108.19:2017: Tile Standard Specifications for Gauged Porcelain Tile and Gauged Porcelain Tile Panels/Slabs (Material and Installation Standards)

Products under the standard include:

• Gauged porcelain tiles: less than 1 square meter
• Gauged porcelain tile panels/slabs: 1 square meter or larger.

Major Tile Resources

• The Tile Council of North America (TCNA) also publishes guidance, including the 2019 TCNA Handbook for Ceramic, Glass, and Stone Installation.
• The Ceramic Tile Distributors Association (CTDA) provides resources for specifiers, as well as homeowners and the industry.
• The Ceramic Tile Education Foundation (CTEF) and Advanced Certifications for Tile Installers (ACT) are tile installer certification programs.
• International regional organizations, such as ACER (the Spanish acronym for manufacturer’s association in Spain) and ITC (the Spanish acronym for the technological institute of ceramics) work with ISO committee working groups and provide research and development and promotion of innovation. University collaborative initiatives with both these organizations and leading graduate faculties like Harvard Graduate School of Design continue to push the boundaries of possibility with ceramics.

  ISO also continues to work on standards for Europe, where these products have been in use much longer than in the United States. There is considerable useful cross pollination between many of the working group stakeholders and ANSI and ISO standards policy makers.

• Tile is an important component not only as a cladding or surface finish but also in systemic design for the Collaborative for High-Performance Schools, the International Green Construction Code, Passive House, and other performance building platforms.

Installation Options

Specifiers should also be aware of opportunities for collaborative installation presented by new gauged porcelain tile products. Although experienced and preferably certified tile installers are critical to most tile installations, new gauged tiles are often not traditional mortar systems. The flexibility of gauged tiles means that other associated trades with applicable skills can often play a major role, particularly in the more creative custom designs now possible. Examples include:

• Facades: engineering/scaffolding contractors, carpenters
• Pavers: landscape design/build contractors, masonry contractors
• Worktops: stone fabricators
• Furniture and veneers: custom furniture fabricators and millwork shops

Basic Tile Categories

There are a number of ways to categorize tile types to narrow the field for specific applications. For example, tile can be ranked by percentage of water absorption as determined in testing. High-absorption tiles are produced at lower firing temperatures and available in many finishes and color choices but suitable mainly for vertical areas. Despite their relatively high porosity, these products are perfectly suited to wet areas due to their imperviously glazed surface and the natural sheeting occurrence due to gravity.

Many moderate- and low-absorption tiles can be used in various applications that are subject to occasional moisture. The lower the moisture absorption percentage, the more traffic and other stressors they can withstand.

At the other end of the spectrum, porcelain tile has extremely low water absorption (less than 0.5 percent) and can be used in any interior or exterior application, including those experiencing heavy or wheeled traffic and even submerged applications.

In another way to evaluate a specific tile’s applicability, the Porcelain Enamel Institute rates glazed tile by hardness. It is important to note that the actual test for abrasion resistance is a visual observation. Lighter colors and collections with variegated pattern or sheen levels will always have a higher PEI rating than darker and/or solid color collections with consistent surface finishes.

• Group I, Light Traffic: These tiles can be used in residential bathroom floors, such as a guest bath where bare or stocking feet are the norm.
• Group II, Medium Traffic: These tiles are designed for use in interiors where little abrasion occurs, so not recommended anywhere exposed frequently to exterior footwear or soil like kitchens, entries, or stairwells.
• Group III, Medium-Heavy Traffic: These tiles can be used anywhere inside a residential home, including kitchens and baths.
• Group IV, Heavy Traffic: These are very hard tiles that can be used in homes or in light to medium commercial areas.
• Group V, Extra-Heavy Traffic: These tiles can be used anywhere.

CONCLUSION

The natural material and unique firing process of ceramic tile give it exceptional durability, ease of maintenance, resistance to fire and flood, and last but not least, beauty that has given pleasure to generations. A growing number of state-of-the-art manufacturers are using emerging technologies to create products that take these natural characteristics to a new level, creating tile that is thinner, lighter, safer, and more versatile than conventional tile, but with the same or improved mechanical, structural, and environmental performance. Manufacturers should be able to assist architects, designers, and specifiers in evaluating the expanded choices now available and how they can be used effectively in specific applications.

A global industry leader, Tile of Spain is the international brand representing 125 ceramic tile manufacturers belonging to the Spanish Ceramic Tile Manufacturers’ Association (ASCER). Its objective is to support and promote Spain’s tile manufacturers and industry worldwide. www.tileofspainusa.com