QUESTION

How many bad tiles are acceptable on 300 sq feet floor

ANSWER

ANSWER -  In terms of manufacturing of ceramic tiles, which includes porcelain tiles that are a type of ceramic tile, there are quality control standards in ANSI A137.1  that allow a small percentage of tiles that do not meet the tolerances and that might be considered defective within each manufacturing lot of tile.  The requirements will vary depending on what type of tile is being evaluated.

In terms of tiles that are already installed, there is no standard for allowing for tiles that are defective or installed in a defective manner.  It is expected that all tiles installed should not be defective tiles and they all should be installed properly.