All About Ceramic Tiles

Many homeowners and do it yourselfers have heard the term porcelain tile. This refers to tiles which are made from special “porcelain” clays and have been fired at very high temperatures. This process vitrifies the tile which makes it very hard, like glass. This also makes the tile dense, forms a strong solid structure and a hard surface which doesn’t absorb water (classified as impervious), doesn’t stain, and isn’t affected by wear and tear over time.

There are two main types of porcelain tile. Glazed porcelain and through-bodied porcelain. Glazed porcelain has a body made of the porcelain material and then a glaze is applied over the surface much like a regular ceramic tile. It is fired in a kiln and the result is a very strong bodied tile. Many tile manufacturers are switching their production to porcelain bodied tile because for a slightly higher cost, they can produce a superior grade tile - glazed porcelain tiles.

Through-bodied porcelain does not have a glaze. The clay is pressed and then fired. It may have texture and color applied to the surface before firing but it is still the porcelain material from top to bottom. The result is a strong tile that can withstand extreme surface traffic. There is no glaze that can wear off. If the tile chips, the same or similar color is underneath.

Because of the high cost of manufacturing this type of tile, only a very small percentage of the tiles you might see in a tile store are true through bodied porcelain tiles.

Most often this type of porcelain tile is installed by commercial users who have a need for the strength and durability of through bodied material.

Porcelain tiles typically have water absorption of 0.5% or less. Ceramic tiles have water absorption greater than 0.5%. Because porcelain tiles have a low water absorption, they are usually frost resistant – although, not always. To know if a tile is frost resistant, you should check the manufacturer’s literature and product specs. Porcelain tiles tend to cost more but are well worth the extra cost.

Understanding the terms shade and caliber
Ceramic Tile is a natural material with a natural composition which becomes resistant when fired at very high temperatures. This process, however, can cause slight differences in the shades of color of a tile between one batch and the next. Therefore, tiles are grouped before packaging according to their “dye lots” or shade and their caliber. The “dye lot” (or shade of that batch of material) is then indicated on the label of every box.

This is why when placing your order for tile, it is very important to order enough tile to not only complete the jo ut also to have extra for any repairs that may need to occur sometime down the line. Five to ten percent extra tile on most orders should be sufficient.

Grading of Tile
PEI ratings PEI rates are more applicable for floor tiles and are ratings that measure the abrasive resistance of the tile’s glaze on a scale of 0-5. This test is only for glazed tiles and does not apply to unglazed porcelain tile or other unglazed types of tile.

Class 1 (PEI 1): Recommended for wall use
May be used both on interior walls or bath floors without direct access to outdoor elements. 

Recommended for tiles that are suitable for residential bathrooms with light barefoot foot traffic. Some wall tiles may be used on the floor.

Class 2 (PEI 2): Light Residential Use
May be used where abrasive foot traffic is minimal – such as bathrooms, bedrooms, dining rooms, living rooms, and sunrooms. Tiles can be used in residential areas, but not areas with high foot traffic such as kitchens, hallways etc.

Class 3 (PEI 3): All Residential floors
For floors subject to normal foot traffic and usage (including kitchens, outdoor entryways and hallways). These tiles can be recommended for all residential installations with normal foot traffic.

Class 4 (PEI 4): All Residential floors and light-medium Commercial floors with moderate traffic Suitable for light to medium commercial applications. Will withstand light to moderate foot traffic in many commercial areas (commercial kitchens, hotel rooms, small offices, etc).

Class 5 (PEI 5): All Residential and busy Commercial
Ideally suited for all residential and heavy traffic commercial areas under normal foot traffic conditions (shopping centers, hotel lobbies, hospitals, and industrial applications). For very high traffic areas, consider an unglazed through-body color porcelain.