General Characteristics

All of the raw materials that go into making ceramics come from the earth, including the colors of glaze - this is a real testament to the quality of the product. While there have been successful methods to improve most products by substituting natural materials with synthetic, like vinyl and carpet, there are no such methods to improve the quality of the raw materials found in ceramics. They have changed very little over the past thousand years.

All tiles share unique and exceptional qualities found in no other type of decorative building products.
Color Permanence

While most colored materials will be altered by long exposure to light, colors in ceramic tiles are unaffected and will not change or fade from exposure.
Abrasion Resistance

How will a tile’s glaze or surface hold up under continuous wear? This is a very important consideration when choosing any glazed floor tile. Commercial areas, as well as areas of the home subjected to heavy usage, such as kitchens or foyers, demand good abrasive resistance. If the right product is chosen and if it is maintained properly, (kept free of sand and grit), it could easily last the lifetime of the home.

NOTE: Abrasion resistance is not a factor when selecting an unglazed tile.
Water Resistance

The glaze on ceramic tile is non-porous. Therefore, when referring to water absorption, it pertains only to the tile’s body. The water absorption of the tile is important to know in order to make the right selection for outdoor use. If the tile absorbs more than 3% moisture, it is not suited for outdoor use in cold climates where it may freeze and crack.
Frost Resistance

Frost resistance goes hand in hand with water absorption. The less water the tile absorbs, the greater it’s frost resistance. Your labels will clearly identify those tiles which are frost resistant.
Stain Resistance

Ceramic material in general is the most stain resistant building product in the world. Glazed tile and even some unglazed tiles resist practically all solutions that could cause staining in other types of products.
Slip Resistance

The slip resistance of ceramic tile in ordinary applications is comparable to that of most hard surface flooring materials and it is significantly better than some. Unglazed tiles have greater slip resistance than glazed tiles and are recommended for areas subjected to high water spillage. Many glazed and unglazed tiles also feature an abrasive grit on their surface, increasing their slip resistance substantially. These tiles are particularly suited to public areas with direct access to the outdoors.
Dirt Resistance

Ceramic tiles do not retain dust or residues. Plain water or a damp cloth is generally all that is required to keep the tile clean. With the exception of tiles such as Terra-cotta, which may be optionally oiled or waxed, no polishing or buffing is necessary to maintain the finish.
Fire Resistance

Ceramic tiles are completely fire-proof at any temperature. They will not burn nor fuel a fire. The surface will not alter, nor will it give off any toxic gases, smoke or fumes during a fire.

In addition to being fire-proof, tiles have also been found to provide protection for structural surfaces during fires.

The face of ceramic tiles will not retain liquids, absorb fumes, odors, or smoke. This allows for good hygiene. Tiles are suited for any environment where hygiene is essential.
Clay Body
  • The clay body, which is also called the bisque, consists of various types of clay and other minerals. Combined, these raw materials give the bisque its strength and stability.
  • The strength of the bisque is also determined by its density. The strongest bisques, those suited for heavy commercial installations, have the smallest and least number of air pockets.
  • The density of clay also determines if the tile is suitable for outdoor use. Tiles that are too porous, absorbing more than 3% moisture will freeze and crack if installed outdoors in cold climates.
  • The density of the tile is measured by the amount of water it absorbs.
  • Non-Vitreous Tiles – absorb 7% or more of their weight in water. Suited for indoor use only.
  • Semi – Vitreous Tiles – absorb 3% to 7% water. Suited for indoor use only
  • Vitreous Tiles – absorb 0.5% to 3% water. Suited for both interior and exterior use. They are frost resistant.
  • Impervious Tiles – absorb between 0 and 0.5% of their weight in water. Suited for both interior and exterior use. They are frost resistant. They are also considered the strongest tile.
  • The glaze is a liquid glass that has been sprayed or poured onto the surface of the tile. It is then fused and hardened by means of tremendous heat.
  • The colors of the glaze are made from a mixture of minerals such as gold, silver, zinc, copper, mercury, cobalt and many others.
  • The strength and wear resistance of the glaze is determined by its hardness. The following factors may effect this hardness:
  • Temperature - The higher the temperature of the kilns (ovens) the harder the glaze.
  • Colors - Dark color glazes such as blacks and blues are usually softer than light colored ones.
  • Gloss Levels – Shiny glazes are usually softer than matte or satin finished glazes.
Difference between glazed and unglazed tiles:

Glazed Tiles are made the same as unglazed except that a glass wear-layer, called a glaze, is fused to its surface by means of tremendous heat.

Unglazed Tiles are true inlaid. They are simply baked pieces of clay whose colors run throughout the body.

Features of glazed and unglazed tiles:

Glazed Tiles:
  • Most glazed tiles are not suited for heavy commercial installations. They are generally suited for light residential to medium commercial use.
  • Technology for glazes has improved dramatically over the past few years. There are new glazes on the market that are hard and durable enough to use in heavy commercial applications.
Advantage of glazed tiles:
  • The glaze offers the manufacturers the ability to produce an unlimited array of beautiful colors and designs.
  • The non-porous glaze creates a smooth surface that is practically stain proof.
Unglazed Tiles:
  • Unglazed tiles are the workhorses of the industry. They are generally thicker and denser than glazed tiles. Some common types are quarry tiles and porcelains.
  • The tough inlaid qualities of most unglazed tiles makes them ideally suited for, but not limited to, extra heavy commercial installations.
  • Many customers appreciate the natural qualities and beauty of unglazed tiles and choose them for residential areas.
  • Generally, the color range of unglazed tiles is limited to the natural colors of clay…ranging from a light sand to a red brick, but there are exceptions.
  • Some manufacturers achieve a wide range of beautiful colors by mixing color pigments in the clay.
Advantage of unglazed tiles:
  • Superior strength for heavy commercial use as well as residential.
  • The rugged surface texture and matte finish of the unglazed tile give them superior “slip resistant” qualities for use in wet areas.

Glazed ceramic tile varies in gloss levels depending on the look the manufacturer wants to achieve. Levels can range from matte or satin to high gloss.

Generally speaking, the higher the gloss, the softer the glaze. Areas of the home that don’t receive heavy wear, such as bathrooms, use a higher gloss level than heavy traffic areas, such as kitchens.
Wall Tile

Any ceramic tile is suitable for walls, but the very thin, high glossed and decorative tiles are most commonly used.

The most popular size for wall tile is still 4 ¼" x 4 ¼", but there is a trend taking place for larger, more luxurious tiles.

True "wall" tiles have a very soft glaze and porous body and therefore should never be used on floors or for outdoor applications.
Floor Tile

These tiles, glazed or unglazed, have sufficient strength, impact and abrasion resistance to withstand weight and foot traffic.

They are usually thicker, denser and heavier than wall tiles.

If the substrate is strong enough to support the weight, floor tiles may also be used on walls and counter tops.

A certain degree of shade variation is inherent in all ceramic tile. In fact, many tiles, both glazed and unglazed, are deliberately produced with a wide shade variation to capture the natural beauty of the product.

The manufacturers limit the amount of shade variation within a carton by sorting the tile as it comes off the production line. Also, the shade and run numbers are marked on each carton.

To minimize any noticeable shade variations, the installers work out of several cartons simultaneously. In doing so, they are able to blend the tiles together.

NOTE: If the shading is too apparent, the installer should not set the tile.

The sizes of the tiles will vary slightly. This is inherent with most tiles. However, most manufacturers will keep sizing to an acceptable level by sorting the tile by size prior to packing it.

Grout joints will help to conceal slight size variations.

Nominal vs. Actual Sizing:

Although most tile is advertised and sold by nominal sizes such as 8" x 8" or 12" x 12" the actual sizes will be more like 7 ½" x 7 ½" or 12 ¼" x 12 ¼".

NOTE: If size discrepancy between tiles is too apparent, the installer should not set the tile.