Tile terminology can be confusing. PEI ratings, glazes and just telling the difference between porcelain and non-porcelain tiles can leave consumers bleary-eyed. To help you navigate these issues and find the right tile for your particular application, the information below includes descriptions of the different types of tiles, from ceramic to marble, as well as details on wear ratings.
Most types of tiles that are made from a form of clay or a clay mixture, which are then kiln-fired, are considered to be a part of the larger classification of tile called ceramic. These tiles can be split into two groups: porcelain and non-porcelain. These non-porcelain tiles are commonly referred to as ceramic tiles.
Porcelain or Non-Porcelain Ceramic Tiles
Non-porcelain ceramic tiles are generally made from a red or white clay that is fired in a kiln. They’re easier to cut than porcelain and usually carry a PEI rating of 0 to 3 (see PEI Ratings below). Ceramic tiles are suitable for light to moderate traffic and have a higher water absorption rating that makes them less frost resistant than porcelain. In addition, they’re usually more prone to wear. However, with new technologies, ceramic tile should always be considered by its specifications, as durability and other factors will vary between ceramic tiles. Ceramic tiles generally cost less than porcelain tiles.
Porcelain tile is generally made by pressing porcelain clays, which results in a tile that’s dense, impervious, fine-grained, and smooth with a sharply formed face. Porcelain tiles usually have a much lower water absorption rate than ceramic tiles, making them more frost resistant, although not frost proof. Glazed porcelain tiles are much harder and have more wear- and damage-resistance than ceramic tiles, making them suitable for any residential and light commercial application.
In order to enhance the stain resistance of a stone tile, many tiles are glazed. This means they’re coated with a liquid glass that’s baked onto the surface of the clay. In addition to protecting the tile from staining, the glaze also allows an unlimited array of colors and designs to be added to the tile. Porcelain tiles whose color runs all the way through the tile, rather than simply being baked onto the surface, are called full-body tiles. Since their color extends throughout the tile, these tiles don’t show wear, making them ideal for commercial applications.
Ceramic Tile Wear Ratings
The current rating system for ceramic tile is the only reliable gauge for consumers to use in determining wear expectations for a particular tile application. The porcelain Enamel Institute (PEI) has developed a rating scale that can effectively guide any consumer through the process of choosing the right tile for their particular application. This rating system is recommended by the American Society for Testing and Materials (ASTM).
PEI Class 1 Rating (No foot traffic) – Recommended for wall use only in residential and commercial applications.
PEI Class 2 Rating (Light traffic) – Recommended for both wall use and bathroom floor applications.
PEI Class 3 Rating (Light to moderate traffic) – Recommended for countertops, walls, and floors where normal foot traffic is expected.
PEI Class 4 Rating (Moderate to heavy traffic) – Recommended for all residential applications as well as medium commercial and light institutional.
PEI Class 5 Rating (Heavy to extra heavy traffic) – Recommended for all
residential as well as heavy commercial and institutional applications.
Most porcelain tiles have a PEI rating of 5, which makes them the hardest wearing tiles on the market.