Tiles are a mixture of clays that are pressed into shape and fired at high temperatures which gives the tile it’s hardness. The bisque (body) of ceramic tile may then be glazed, or left unglazed depending on it’s intended use.
Classifications of Ceramic Tile
P.E.I Wear Ratings from the Porcelain Enamel Institute
Group I: Tiles that are suitable for residential bathrooms with light foot traffic . Generally wall tile products fall into this group. Some wall tiles can be used on the floor. Consult the manufacturer of the tile for their recommended areas of application.
Group II: Tiles that can be used in residential areas, but not areas with high foot traffic, such as in kitchens, foyers, laundry rooms, etc.
Group III: Tiles that are recommended for all residential installations with normal foot traffic.
Group IV: Tiles that are suited for light to medium commercial applications, such as offices, sales rooms.
Group V: Tiles used in heavy commercial traffic areas and are suited for exterior areas, shopping centers, airports, hotel lobbies, public walkways.
Types of Tiles
Ceramic Mosaic Tile – tiles that are less than 6 inches facial area and may be either porcelain or natural clay composition and usually are 3/8″ or less in thickness.
Quarry Tile – tiles made from the extrusion process from shale or natural clays and usually are 6 square inches or more in facial size and can be glazed or unglazed.
Paver Tile – glazed or unglazed natural clay or porcelain tiles having a facial area of six square inches or more and made from the dust-pressed method.
Wall Tile – glazed tiles with that are designed for indoor use and are generally non-vitreous.
Common Tile Terms
Glazed – The most common style today in floor and wall tiles, as well as for residential and commercial applications. A liquid glass is applied to the body of the tile and fired at high temperatures. The glazing becomes hard and non-porous resulting in a flooring that is:
- Stain Resistant
- Scratch Resistant
- Fire Resistant
- Doesn’t Fade from Sun Light
- Slip Resistant
- Easy to Clean
Shiny glazes are softer, can be scratched easier, and can be slippery than the satin or rustic finishes.
Unglazed – There is no glazing or any other coating applied to the tile. Their color is the same on the face of the tile as it is on the back resulting in very durable tiles that do not show the effects of heavy traffic. The most common unglazed tiles are the red quarry tiles or the granite looking porcelain ceramic tiles used in heavy commercial areas.
Saltillo Tile – is a Mexican tile made of unprocessed clays.
Listello – a narrow tile used to accent field tiles.
Tile Density & Moisture Absorption
Tile Density – As the weight or the density increase it becomes a stronger tile.
Moisture Absorption – Again as the density increases the amount of moisture that a tile can absorb becomes less.
Tile density and moisture absorption have an indirect relationship to each other. As the density of the tile increases the moisture absorption rate becomes less. Tile density and moisture absorption are important to understand when selecting the tiles for different applications.
Non-Vitreous Tiles – tiles with a water absorption of 7% or greater (wall tile). Suited for indoor use only.
Semi-Vitreous Tiles – tiles with a water absorption greater than 3%, but less than 7%. Suited for indoor use only.
Vitreous Tiles – tiles with a water absorption less that 3% moisture, but more than 0.5%. Referred to as frost resistant tiles but can not be used in exterior areas where freeze thaw conditions could cause tile cracking.
Impervious Tiles – tiles that have less than .5% moisture absorption (Porcelain tile). These tiles are frost proof and can be used in exterior areas, or on the outside of building facades.
Tile Production Methods
Bicottura – It is an Italian word meaning “double fired”. The clay body is fired on the first pass through the kiln, and the glaze is applied and fired on the second pass through the kiln. This process is only being used today for decorative wall tile products.
Monocottura – It is an Italian word meaning, “single fired”. The tile passes through the firing process one time at a temperature of 2200 degrees. Monocuttura tiles have denser bodies and harder glazes than Bicottura tiles.
White Body Tile versus Red Body Tile
The color of the body is determined by the color of the clay used by the manufacturer that is available in their geographic region. Look at the body of the tile to see if the color is red or white. The quality of the tile is more related to the quality of the manufacturer not the color of the body.
Wall Tile Trims
Bullnose – This is the most used trim shape for wall tile installations. Wall tile bullnose is sometimes referred to as surface cap . It has one rounded finished edge on the tile and can be used horizontally or vertically. For a 4″ x 4″ tile the industry number would be S4449.
Corner Bullnose – It has two rounded finished edges on the tile to be used to complete the corner where the horizontal and vertical bullnose meet. Generally you use only 2 – 3 pieces for a bathtub enclosure. For a 4″ x 4″ tile the industry number would be SN4449.
Stack-on Cove Base – This cove base provides a coving on the bottom and a flat edge on top to continue with more wall tile up the wall. For a 4″ x 4″ tile the industry number would be A3401.
Rounded Top Cove Base – This cove base has a rounded finished top like bullnose and is used as a cove base in areas that will not have wall tile installed above it. The industry number would be S3419.
The above trims are the most commonly used. There are many other specialty trims available that will only confuse you. Your tile installer will be able to look at your installation and know what trims will be needed.