Identifying the manufacturer of ceramic tile from maker’s marks can range from fairly simple to almost impossible. Every ceramic-tile manufacturer in the United States has maker's marks on the back that can be found if you know what you're looking for. The majority of standard 4-inch ceramic tile used for bathroom walls and floors falls within the "easily identified manufacturer" category.
If you don't have a loose tile, remove a tile from the wall or floor. Use a putty knife to scrape off drywall paper, glue and grout from the back. At a minimum, clean off the edges and the centre.
Examine the back of the tile for raised lettering along the edges and in the centre. Also examine the location and layout of the ridges used to help the tile bond to the adhesive.
Compare the letters or marks on the tile to those in the list below. Tile made by the first two manufacturers makes up about 75% of all ceramic tile installed in bathrooms in the United States.
American Olean: “AO” in the centre or along one edge of the tile.
Dal-Tile: “Dal-Tile” in the centre of the tile.
Florida Tile: “FT” along one edge of the tile. Note that at 4 3/8 inches, "4-inch" tile manufactured by Florida Tile is among the largest.
Universal Tile: Four diagonal ridges in each of the four quadrants. The centre of the tile has no markings.
Wenczel Tile: “Wenczel” stamped in the centre of the tile.
RAK Ceramics: Stylized crown in the centre of the tile. RAK is one of the few manufacturers outside the United States that marks the backs of tiles.
If the tile was well stuck and removing glue and drywall is difficult, soak the tile in water overnight. If the adhesive is still resistant, use a commercial glue solvent to remove it. If you can’t identify the tile based on the above information, take it to any of the tile manufacturers listed. Someone there can identify the manufacturer and help match the tile, no matter who the manufacturer is. Take tile to a business that sells only tile, not to a home building centre or other generic construction/repair materials business. Ceramic tile made in other countries usually has no identifying mark on the back. Neither does quarry, mosaic, marble, porcelain and other types of floor tile.
Identifying the manufacturer enables you to not only match the colour but also the size. Even though most ceramic tile measures nominally 4 inches square, actual size can vary by as much as 3/8 of an inch.