Aquatic Technology Pool & Spa, "Creating Water as Art."™

Aquatic Technology Pool & Spa, "Creating Water as Art."™
Pools as an art form - the way it should be!

Thursday, December 12, 2013

Discoloration Glass Tile Mosaics

Expert Witness Glass Tile Mosaics Installations
Glass tile installations cost a lot of money.  Let's face it, if it was inexpensive to install glass tile mosaics properly, then everyone would have glass tile mosaics.  They are the most luxurious finish available for swimming pools and spas.

Glass Tile Gone Wrong

A glass tile mosaic job can look terrible when done wrong.  Most problems are caused by installation errors.  Compounding the problem, are the use of translucent (see through) glass tiles.  They permit the installation errors, normally hidden by ceramic tile, to shine through!

Causes of Discoloration
The most common causes of discoloration behind glass tile mosaics are a result of:
  • using gray cement, mortars or setting materials
  • not keeping the tiles shaded until the pool is filled
  • failing to protect the tiles from rain or irrigation water
  • allowing the bond coat to skin over (poor bond, voids)
  • excess water in the bondcoat (thinset)
  • incorrectly using the direct set (two step) installation method
  • leaving trowel marks
  • grouting too soon (not allowing the bondcoat to fully cure)
  • filling the pool too soon after grouting
  • fielding mixing setting materials (results in unknown bond and compression strengths, density and permeability)
  • not using a waterproof membrane
  • too thin of a bondcoat (allowing the membrane to shadow through)
  • allowing ground water to soak through the pool shell 
  • contamination in the bondcoat
These are just some of the most common mistakes.  Individually or in combination, they can result in a beautiful pool turning into a hideous mess.

Workmanship Standards

In North America there are published and accepted workmanship standards.  These standards are the minimum that apply to the installation of glass tile mosaics.  So, regardless of what installation method the tile manufacturer or contractor recommends, THESE ARE THE MINIMUMS.

Foreign manufacturers are not aware that the tile industry in North America has performed significant testing and analysis if glass tile mosaic installation practices.  They have established acceptable methods of installing glass tile mosaics that apply to EVERY INSTALLATION in North America.  They are the GOSPEL for glass tile installations.

These practices are published under the ANSI A108.14, A108.15 and A108.16: Standards for the Installation of Glass Tile Mosaics.  They also make direct reference to the quality and performance standards for the required mortar beds, waterproof membranes, bondcoats (thinsets) and grouts (ANSI A118).

Because there are performance standards for the mortarbeds, thinsets (bondcoats) and grouts, the field mixing of raw materials cannot guarantee that they meet the ANSI performance standards.

Paolo Benedetti - Aquatic Artist 
"Creating water as art."™ 
Aquatic Technology Pool and Spa © 
You may contact Paolo Benedetti at: or at 408-776-8220