Ceramic tile has been used as an artistic, functional, and enduring building material for the last 4000 years or more. Ceramic tile is nothing more than a mixture of clays which are shaped and fired at a high temperature to create a hard, dense product. This product can be left untreated or receive a glazed wearing surface.
All of the clays and minerals that are used in creating ceramics, including the glaze colors and textures, come from the earth. Throughout the years, man has always tried to "improve" upon the materials he uses to create various building products. For example, gypsum board has seen the recent additions of materials and chemicals to make the product more mold resistant; carpet has enjoyed the additions of synthetic materials like nylon, olefin, and other fibers. The fact that the clays and minerals used in ceramic tile have not changed speaks highly of the product's long success.
After the raw materials are quarried, prepared and mixed, the clay bodies or 'bisque' are formed. The combination and mixing of the raw materials give the bisque its strength and quality. There are a number of forming methods, including: dry pressing the mixture into a mold; extruding slightly wet material through a mold to create a shape; or slush mold or wet pour forming, where the wet materials are poured into a mold. The density of the bisque is also a measure of its strength. Density is a measure of the water absorption ability, and the strongest bisque will have the fewest air pockets produced as the clay in the molds dries. Once it has been completely air dried and a significant percentage of the moisture has been released, the bisque is fired in a kiln at very high temperatures to harden it. This creates the unglazed tile, which could be installed as-is, although unglazed tile usually does not have the desired level of attractiveness.
Glazing refers to the surface application of glass materials that are dipped, sprayed, poured, and even silk screened on. Colors of glazing come from the addition of mixtures of various minerals, including copper, silver, gold, cobalt and others. The tile is again fired at very high temperatures. This is called the second firing, and it also creates a very hard, dense surface. Historically, ceramic tiles have been produced with this two step firing process, but in a world of rising labor costs and increasingly more automated manufacturing, a process was developed to fire the bisque and glaze in a single operation. This process is called "monocottura", an Italian word for single-firing. Although many tiles are still produced with the two pass method, the majority are more cost effectively produced with the monocottura method.
Any tile product has the potential to offer decades of service, provided that the installation is correct. Ceramic tile owes its longevity and service completely to the construction materials supporting it. Centuries ago, buildings were mainly constructed of mass stone, and later concrete. This construction formed a rigid substructure, onto which tile could be directly installed. In today's construction, where we see taller buildings and longer spans, it is important to use the correct backer board under tile in order to distribute the floor loads and to prevent flexing. It should be noted that selection of a backer board for a wall application is not quite as critical. The improvement of adhesive mortars and joint grouts, as well as the increasing ability to control building expansion/contraction, are other noteworthy improvements which impact in the industry.
The ceramic tile industry is more than willing to provide correct installation instructions in order to ensure a tile's long term performance. The best approach is to take advantage of the manufacturer's technical support, and follow their instructions closely.
Ceramic tile combines beauty, durability, and excellent performance in a versatile surface material. Whether for floors, walls or decorative applications, its usage is limited only by the imagination.
See also, Ceramic Tile Murals