Glazed and Unglazed Tile Types
Glazed tiles have either a glossy or a matte waterproof surface glaze. Nonskid tiles have an abrasive grit baked into the glaze.
Mosaic tiles have the color added to the clay itself, so it goes all the way through the tile. They’re suitable for nearly any surface.
Quarry tiles are usually deep red and unglazed. They’re porous, and are mostly used for interior floors. They must be sealed after installation or they will be easily stained. Install with thinset (see Setting Tile).
Paver tiles are also used for floors and are usually unglazed, requiring sealing. The machine-made types are typically vitreous and non-vitreous. The hand-made type is non-vitreous. Install with thinset.
Most manufacturers use the Porcelain Enamel Institute (PEI) guide to rate the durability of tile (Figure A).
|Group I||Tiles suitable for residential bathrooms only where softer footwear is worn, or on walls.|
|Group II||Toles suitable to general residential traffic, except kitchens, entrance halls, and other areas subject to continuous use.|
|Group III||Tiles suited for all residential and light commercial areas, such as offices and reception areas.|
|Group IV||Tiles suited for medium commercial and light institutional applications, such as restaurants, hotels, hospitals lobbies, and corridors.|
|Group V||Tiles suitable for heavy traffic and wet areas where safety and maximum performance are a major concern. These include walkways, food service areas, shopping centers, building entrances, and around swimming pools.|
The capacity of a tile to absorb water is determined by its firing temperature, duration of firing, and composition of the clay. Ratings range from non-vitreous (porous) to impervious (Figure B). Do not use highly absorptive tile, such as quarry tile, in wet areas. If this can’t be avoided, install waterproofing under the tile and add a latex additive to both the thinset adhesive and grout. Avoid mastic set tile in wet areas.
|Tile Type||Water Absorption||Application|
|Impervious||less than 0.05%||Hospitals, sanitary installations|
|Vitreous||0.5% to 3.0%||All residential applications, good for floors|
|Semi-Vitreous||3% to 7%||All residential applications except outdoors in cold climates. Mist before grouting.|
|Non-Vitreous||over 7%||Best in dry application. Mist before grouting.|