To provide a quality tile installation, there are several pieces of information that must be verified to yield a satisfactory result. Checking the label on the side of the tile box will supply some essential information. All the contained information, which we will review, is important, but the two most critical items are the shade or tone and caliber or size of the tile.

The American National Standard Institute (ANSI) Terminology of Tile Assemblies A108.T contains definitions taken from ANSI A137.1, the American National Specification for Ceramic Tile, as follows.

Caliber Range: An acceptable size range for tiles to be used in the same installation. 

Calibrated Tile: Tile that have been sorted to meet a manufacturer’s stated caliber range.

Shade or Shade Value: A manufacturer designation [normally a number(s) or letter(s)] printed on the box or label that signifies that particular box of tile is visually suitable for use with other boxes having identical shade value.

Also stated on the label we are reviewing is the term, Not Rectified.

Rectified: A tile that has had all edges mechanically finished to achieve a more precise facial dimension. 

The Tile Council of North America (TCNA) Handbook has a great statement under the heading, “Dimensional Consistency” that states, “Tiles may be rectified (mechanically finished along their edges to achieve more precise facial dimensions), calibrated (sorted to meet a specified caliber range), or “natural” (packaged directly after manufacturing with no rectification or sorting).    

In this case, the tile in the box has not been rectified or ground to a tighter tolerance and is therefore known as a calibrated tile. This is not to say that calibrated tile is of a lesser quality than rectified, but a different classification. Most of the tile sold in today’s market is calibrated which works well for its intended purpose.

Additionally, be certain to confirm that each box being purchased for your job has the identical information on the label as seen in the attached image. All the boxes state; Grade 1, Shade BF6, and Caliber 3 which means they will work well together. Mixing boxes with different caliber and shade designations, can deliver unacceptable shading and grout joint sizing issues. 

Do yourself a favor, take a moment to check the numbers/letters on the box, saving yourself the grief of a more difficult installation and, potentially, a job that may be rejected by the end user.