2024-25_NTCA_Reference_Manual_dig_dwnld

Lippage or Uneven Natural Stone Tiles "Lippage" is a condition that occurs when adjacent tile edges are not flush (coplanar) with one another.

Problem

Prevention

Cure

Uneven substrate surface.

Prepare substrate surfaces according to "Proper Preparation and ANSI Require ments for Thin-set Method Tile Installa tion." (See page 43.)

Remove and replace high tiles. Grind and refinish tiles or replace stone tiles after grinding off substrate high spots. Fill low spots with self leveling underlayment or floor preparation underlayment.

Floor should be refinished by qualified persons.

Insufficient or uneven coverage of the bond coat or mortar bed.

See page 190 “Proper Bedding Procedures.”

Grind and refinish or replace stone tiles.

Floor should be refinished by qualified persons.

Varied stone tile thickness.

Examine tiles to determine consistency of tile thickness. Use box screed for ex cessive thickness variation. Conventional mortar installation will minimize effect of varied thickness. Use a large and heavy tile (LHT) mortar. Use materials recommended by the bond ing material manufacturer for the desired installation. Mix according to manufactur er's instructions.

Grind and refinish or replace stone tiles.

Floor should be refinished by qualified persons.

Improper mixture or wrong bonding ma terial.

Grind and refinish or replace stone tiles.

Floor should be refinished by qualified persons.

Insufficient leveling of each individual stone tile.

See page 190 “Proper Bedding Procedures.”

Grind and refinish or replace stone tiles.

Warping caused by water (most green marbles and some other moisture-sen sitive stones).

Set material with epoxy.

Remove and replace tiles.

Apply liquid waterproofing membrane or primer to back of stone tile. Consult mem brane or primer manufacturer.

Get better bad stone tile install.

NTCA Reference Manual | 2024 / 2025

167

Chapter 6 | Natural Stone Installations