This evaluation method involves utilizing a standard-sized card, similar to those issued by financial institutions, to assess the evenness of a tiled surface. The card is placed across the edges of adjacent tiles to identify any height differences, which are indicative of uneven installation. A noticeable obstruction or inability to smoothly pass the card signifies unacceptable variation in surface level.
The practice offers a quick, on-site method to verify tile installation quality, reducing the need for specialized measurement tools. It provides a readily accessible and easily understood criterion for determining whether the finished surface meets acceptable tolerance standards. Historically, it evolved as a practical approach to address common issues arising from inconsistent tile setting, impacting both aesthetics and functionality.