Glass Tile Mosaic Swimming Pool

Unexplained cracking of glass tile mosaics in a swimming pool or spa are more than likely an issue of recycled content or impurities in the glass.

Random cracking failures of Oceanside Glass Tile Mosaics.

Blend: Random Modular Enchantment Tessera 

 

(click on the image to enlarge it)

If your glass tile swimming pool or spa experiences random cracking in glass tiles, it is more than likely a manufacturing defect, than an installation error.

Unexplained failures of Oceanside Glass Tile Mosaics in a swimming pool

 

(click on the image to see the crack failures close up)

But how do you prove this?  

Mount the tiles on a sheet of 3/4 inch CDX plywood, following the proper cure times for thinset and grouts.  Place the plywood into the same environment as the cracking tiles.  Place a duplicate sheet into the direct sunlight.  Place a container (tupperware tray) of loose tiles into the same environments.

If the loose and mounted tiles randomly crack, then there is a manufacturing defect.  Additional testing will be required to determine the exact cause.

If only the mounted tiles crack, then there is an issue of thermal expansion.  The cracking is occurring because the tiles are constrained by neighboring tiles and grouts.  Laboratory testing will conclusively vet the cause.

If only clear mounted tiles cracked, then there may be an issue of the thinset heating up in the sun.  The clear tiles usually pass more IR light resulting in excessive heating of the substrate.  This circumstance will require additional laboratory testing to validate the hypothesis.

If you are thinking about installing glass tile mosaics into your swimming pool.. find out if the thermal shock testing of the tiles was performed in the mounted condition (installed and constrained) or loose.  

Loosey goosey is muy malo! 
(loose testing is very bad)

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

Cracks - Recycled glass tiles pools spas

The most frequent common denominator seen by expert witnesses when inspecting cracked mosaic glass tiles in swimming pools, has been the use of recycled glass as a raw material.

Beyond their control

Recycled glass is supplied to the tile manufacturers already ground up.  This ground glass is know as cullet.  The standards established by the recycling industry permit cullet to contain impurities.

The Glass Packaging Institute standards state:  "Some recycled glass containers are not able to be used in the manufacture of new glass bottles and jars or to make fiberglass. This may be because there is too much contamination or the recycled glass pieces are too small to meet manufacturing specifications.... This recovered glass is then used for non-container glass products. These "secondary" uses for recycled container glass can include tile, filtration, sand blasting, concrete pavements and parking lots."  

They are saying that contaminated cullet should be sent to glass tile manufacturers!

The processing of cullet attempts to remove impurities.  By their own admission, sifting, electromagnets and optical inspection does not remove the tiniest of impurities.  Small metallic particles are the most difficult to identify and remove.  Non-ferrous metals (stainless steel, nickle, copper, aluminum, magnesium, maganese) cannot be removed with magnets.  These very contaminates can be the very cause of cracking in finished tiles.

Chemical Balance

It is possible for tile manufacturers to chemically counteract the negative effects of some impurities, but not all - especially metals.

Metal Stones

Metal particles are referred to as "stones."  Over time, these stones change in structure.  These changes cause internal stresses within the tiles.  Eventually the stresses grow to the point where the glass cracks.  Microscopic in nature, they are virtually invisible to the naked eye and beyond the ability (or manufacturer's desire) to be detected.

Refractory brick commonly errodes from the walls of the kiln, and becomes a contaminate within the molten glass.  These are also called stones.  Future thermal changes to the tiles will cause cracking, due to the differential expansion of materials.
 

Recycled Glass - Warm Fuzzies and Headaches

Using recycled glass as a component of glass tile production lowers raw material costs and provides consumers warm fuzzies.

The probability of contaminates is too high and potential for failures too great, to justify the installation of recycled glass tile mosaics in a swimming pool.

There are many first quality glass tile mosaics on the market to select from, to even risk considering tiles utilizing recycled glass content.

Once tiles begin to crack, water will infiltrate and soften the thinset.  Sharp shards of loose cracked pieces of tile in a pool or spa pose a threat to bathers.

The cost to remove glass tile, repair the substrate and membrane and reinstall new tile is double the cost of a new fresh installation.

Roll the dice or make a sure bet... the choice is yours.

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