Shower grout cracking

Close-up of severely cracked and discolored grout lines in a tiled shower wall, indicating water damage.
Photo: Nothing Ahead / Pexels
A specialized oscillating tool with a grout removal blade being used to meticulously remove old, damaged grout from between shower tiles.
Photo: Vladimir Srajber / Pexels

Watch: How to Repair Cracked Grout

How Do I Clean and Repair Grout? | DIY Basics via Lowe's Home Improvement

Understanding Tile Lippage

Lippage refers to differences in the height between the edges of adjacent tile modules. This variation in height can be influenced by several factors.

These factors include the allowable thickness and warpage of the individual tiles, the spacing between them, and the angle and reflectivity of the light hitting the surface.

ANSI Standards for Lippage

The American National Standards Institute (ANSI) standard A108.02, Section 4.3.7, defines lippage. This standard acknowledges that the perception of lippage is affected by multiple elements.

The standard also notes that variations in the substrate's plane can significantly impact lippage. When tile is installed over an uneven substrate using the thinset method, the final surface may not meet lippage standards.

Factors Affecting Lippage Perception

The inherent thickness variations and warpage of tile modules, as judged by manufacturing standards, contribute to lippage. The way tiles are spaced also influences whether the change in elevation appears gradual or abrupt.

Furthermore, the angle of natural or artificial light can accentuate variances in tile modules that might otherwise be acceptable. Highly reflective tile surfaces can also make otherwise acceptable variations more noticeable.

Substrate and Installation Impact

Variations in the plane of the substrate are a key factor influencing lippage. An uneven substrate can lead to noticeable differences in the height of adjoining tiles.

When tile is installed using the thinset method over a substrate that is not perfectly flat, the resulting installed surface may not adhere to lippage standards. Proper substrate preparation is crucial for a smooth finish.

Key takeaways

  • Lippage is the difference in height between adjacent tile edges, influenced by tile characteristics and installation factors.
  • ANSI standards address lippage, recognizing that light and surface reflectivity can affect its perception.
  • Uneven substrates are a primary cause of lippage, especially when using the thinset installation method. Use our free tile calculator to estimate your project needs.

Related tools

Estimate materials with our free tile calculator on Tile Calculator.

Sources