Cracked Glass Tile Mosaics - The Flaws Within!

Internationally renown designer, consultant, contractor & expert witness Paolo (Paul) Benedetti offers his opinion as to why many manufacturer's product lines of glass tile mosaics crack. Paolo precisely follows the Tile Counsel of North America (TCNA) and American National Standards Institute (ANSI) installation guidelines & recommendations. Yet, he has had projects where the glass tile mosaics cracked randomly, throughout the installed field in no pattern, & for no apparent reason. He has inspected the work of others, when they also experienced unexplained random cracking & fissures. He has almost 20 years of experience creating spectacular glass tile mosaic knife edge perimeter overflow pools, spas, waterfalls, and water features, infinity edge pools, vanishing edge pools, disappearing edge pools, negative edge pools, no coping pools, zero edge pools, no edge pools, and edgeless pools.

The Flaw's Lies Within... the Naked Truth!

Internal stresses within glass tiles, lie invisible to the naked eye. A tile that looks perfect & unblemished to the unassisted eye, may actually contain inherent stresses that may later manifest themselves as cracks, fissures, or degradation. I have seen these manifest themselves in the manufacturer's very own sample boards and even in unmounted and uninstalled tiles!

For years, the manufacturers have blamed the installers. Why? Because it is very easy to find where the installers deviated even the slightest from the installation instructions. Once there is a crack in that armor, they'll drive a truck through. The suspicion instantly shifts from the possibility of faulty tile, immediately to incorrect installation practices & materials.

Glass tile manufacturers deny that their glass tiles possess any internal stresses. Of course, who in the world would expect them to say, "Golly jeepers, you got us. We really sell an inferior product that possesses inherent invisible internal flaws that will manifest themselves after the tiles are installed." The quote you'll hear is, "they were inspected before they left the factory," or "they weren't cracked when they left the factory."

But, were they really truly inspected? Of course not! Actually, most of the glass tile manufacturers do not even bother to inspect for internal flaws!

Why? Because they are too ignorant (and do not want to know the truth) or they have too much money at stake. Imagine the lost profit, good will, consumer faith, and liability for all of their past inferior production, if they admitted that their products were inherently defective?! Or they are attempting to "compartmentalize" each case of failure, in an attempt to prevent the consumers, government, or attorneys from collectively getting smart & sharing information, and thereby realizing that they're not the only ones who are experiencing this problem (as the manufacturer's will lead you to believe).

If the glass tile manufacturers can keep we as the end users, constantly seeking absolute perfection in our installation procedures, then they will surely take that stance! There are just too many small variables present between different jobsites, applications, & installations to achieve continuity in the installations. The results are that this material seems to be so fragile & delicate - which it is not!
The technical service staff or production managers at most of these firms have not even been provided with the information, training, nor the apparatus to perform the simplest of these inspections. They are simply not aware that the product that they selling is actually flawed!

Like cancer, it's what you cannot see that will hurt you!

So like cancer, in order to detect it early, you need to get "regular screenings." How does this apply to glass tile?

Simple - buy yourself a POLARISCOPE! A what-scope? It sounds expensive!! Well, in actuality they are not - ranging from $250-$1500. The attached images were taken with a hand held digital camera and a $500 polariscope. Many of the manufacturer's do not know what a polariscope is, let alone even own a polariscope. So how do they perform inspections for internal flaws? Simply stated... they don't!

Scary, isn't it?! Once the tiles crack in the field, they get to blame YOU or your installation practices. As their taillights fade in the distance you'll hear, "the tiles did not leave the factory cracked!"

How does a polariscope work? A polariscope is a simple light box, with 2 polarizing filters. The tile to be inspected is laid upon the light table, and the viewer looks through the 2 polarizing filters. These filters polarize & align the planes of light. One of the filters is rotated (or the sample is rotated) to highlight any stresses. As the light passes through the transparent material (in this case glass tiles), the light becomes retarded by any inherent flaws. The more retarded the light, the more stress in the material and the brighter the highlighting. The stress appears as a white "hot spot" within the image.

Some manufactured glass tiles have small surface blemishes (wrinkles, scratches, or chips) that the manufacturer's claim is a part of their "character & uniqueness," when these in fact can impart stresses onto/into the glass tiles. An example of this is when a glaziers scribe (rolling carbide glass cutter) is ran across the surface of a glass tile. Once scribed, that "scratch" actually imparts "stress" into the glass tile... stresses that the glazier actually relies upon in order to crack a sheet of glass in a straight line. The bottom line, is that surface flaws can (but not always) cause stresses within the tiles. Some tiles are manufactured with wrinkles and textures that do not impart any stresses - the buyers & end users need to be informed! The only way to know for sure, is to use a polariscope.

Wait a minute, how can this simple test be so informative? Is it valid? Well the US Food & Drug Administration uses this very device & technique to inspect glass drink and food containers. This link also explains in greater scientific detail how the polariscope works:
http://www.fda.gov/ICECI/Inspections/InspectionGuides/ucm071623.htm

So from now on, when the manufacturer's information says that it is, "the users responsibility to inspect the tiles & verify that the tiles are suitable for the intended purpose," you have a simple apparatus to perform such inspection quickly & inexpensively. By the way, such a warranty disclaimer clause is illegal in California, outlawed in the CALIFORNIA CIVIL CODE SECTIONS 1792-1795.8.

I am not promoting any particular brands of tiles here. I know from firsthand experience that the following manufacturers perform routine random sample testing & observations of their glass tiles. I also have not experienced or observed any major failure issues with any of the following brands (listed in no particular order)*:

http://lightstreamsglasstile.com
http://www.sicis.it
http://www.bisazza.com/usa/
http://www.kolorines.com/
http://www.interstyle.ca/

*Just because a particular brand of glass tile is not listed above, does not not mean that they are not performing these inspections or are having internal stress issues (no, that doesn't mean they've missing their morning cup of coffee). It just means that I do not have any personal knowledge or experience to speak firsthand as to the quality of their products or production process. I am not opposed to accepting a fully paid facilities inspection tour or to accepting material samples to "field test," from any manufacturer's that are not listed. Regardless, I will continue to independently report my field observations & firsthand experiences!

Lest I remind you, that these observations apply to glass tiles - not porcelain or ceramic!

Maybe these flaws are so small, that they are merely slipping through the manufacturing process...?? Hardly... for example, my 10 year old son sorted & picked out the attached tiles (which I photographed) and attached as examples. The small white specs throughout the images are speckles of dust on the lightbox surface.

In the following images internal stresses (seen as white hot spots, streaks & clouding) are clearly visible within the tiles :
The swirling star that is observed in the following image, is what an acceptable tile looks like. The bubbles within the glass tile, do not inherently create stress or weaknesses. You can clearly see that there are no observable stresses surrounding the bubbles.

NOW YOU CAN "SEE..."

...that the flaws may actually lie within, and not with the end user or installer!


Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa
©www.aquatictechnology.com

Glass Tile Mosaics - Unexplained Cracking, Fissures, Spalling, or Failures

Internationally renown pool designer Paolo (Paul) Benedetti presents an end users view into the failure of glass tiles (cracked, fissures, spalling). He has created spectacular glass tile mosaic knife edge perimeter overflow pools, infinity edge pools, vanishing edge pools, disappearing edge pools, negative edge pools, no coping pools, zero edge pools, no edge pools, and edgeless pools.

An Insiders Look
Over the past few years I have examined, studied, discussed or consulted on approximately 100 glass tiles failures. The installations ran the gamut from interior decorative walls & bathrooms, simple glass tile waterlines in pools, elaborate outdoor pools lined entirely with glass tile mosaics, to glass tile manufacture's own factory assembled & provided sample boards!

Following Directions
Let's face it, it's a guy thing... don't ask for directions when you're lost, and by all means don't read the instructions before you've started the assembly/installation!

A number of the installations (most) were installed by people who didn't even bother to read the manufacturer's installation instructions. These projects were destined for failure even before they "hitched a horse to their cart." Combine shoddy workmanship with defective glass tile mosaics, and you have a guaranteed lawsuit - the only ones who wins are the attorneys!

However, some of the installations were performed by individuals as anally retentive as me. They should not have had ANY issues... but they did anyway. These are the projects that I'm focusing on. People who did everything by the book, and still the projects experienced glass tile mosaic failures. These are the people who did nothing wrong. They used the proper setting materials, waited the correct amount of time for the various layers to cure, installed expansion joints in the right places, and documented exactly what they did.

Limiting your Liability with DETAILED Instructions
In order for a General Contractor, Tile Contractor, or Swimming Pool Contractor to minimize their liability they need to be sure that they have specific instructions from the tile manufacturer. You'll notice that I did not say eliminate the liability, as there is absolutely no way to prevent someone from "point the fingers" - and that's exactly the manufacturer's tactic! "It didn't leave our factory that way!" But read on... it probably did (they were just too stupid to know any better, or too deceitful to care!).

You want to find instructions that specify their approved setting materials, and outlining for neophytes the correct curing/waiting times between the installation stages. This is what you want from a set of instructions... details. If the instructions say "any commercially available thinset" (or worse yet "thinset"), or "sanded grout" (do they really mean plain unadulterated grout, with polymer fortifiers, or sanded & epoxy fortified?), be sure to get written clarification! I guarantee you that a they will deny that they ever spoke to you - if all you do call on the telephone. Oceanside Glass tile probably has one of the most detailed set of instructions that I have ever seen. They specify everything!

DOCUMENT, DOCUMENT, DOCUMENT
Did I mention that you should DOCUMENT everything? It is not difficult to note the lot numbers of the waterproofing, thinset, grouts & expansion joint filler when the delivery quantities are verified on the job site. It doesn't have to be anything formal, just a notation of the tracking numbers on the packing slip.

During the installation, the documentation of the curing times can be as simple as a digital camera that date stamps the images as they are taken. After an area is prepared, it can be marked with a marker as to the date finished & the date ready to start again. Then take a picture. When work resumes in this area (on or after the date written with the marker) take another picture. As work progresses to the finish layers, you can use a "china" or grease marker to label the tiles with this information. It'll clean off easily during the detailing stage.

Digital pictures are wonderful, as they can be enlarged, emails, & distributed easily. Be sure to encode the images, so that they cannot be manipulated with post-imaging software (Adobe Photoshop) before they are ever distributed. This same software allows the images to be documented in a manner which will reveal if someone in the future manipulates them. remember - a picture is worth a thousand words.

Failures
Out of the failures that I've seen, there is a resounding commonality.... the use of recycled glass. Granted anytime we can use recycled materials, it is great for the environment. But for some reason, in the manufacturing of glass tiles, it's use seems to be a problem. I have yet to see a problem with blanket failures from any manufacturer who uses ONLY virgin materials in their production process: Lightstreams, Cicis, Colorines, Bisazza, Interstyle. Over the years, I have personally used products from each and every one of these manufacturers, and have yet to experience any issues. I have many of them in my own home... and inspect them frequently!

Why all of the failures?
First of all, a large number of manufacturers have taken their manufacturing facilities off-shore. China has found itself one of the largest manufacturers of glass mosaic tiles. Do you really think that they perform any quality control on the "recycled" glass that goes into their tiles? If they had a single source of their recycled raw materials, they might have an argument. However, this is not the case, green glass is green glass, clear glass is clear glass... glass is glass. Grind up all of these different glasses, that have definitely have different chemical formulations. And Houston, we have a problem.

Name brand manufacturers and boutique designers, saw all of the potential profits in glass tile mosaics, and not wanting to miss a buck, placed their names on this crap. There are no quality control inspections... just delivery schedules and profit margins. Do they even understand the material science side of glass production? I seriously doubt it...

There are a few manufacturers that use a single source of recycled glass, and therefore claim that all of their recycled glass is the same & therefore (it must be) compatible. Let's say for instance, they rely on the use of ONLY clear soda beverage bottles from one brand of soda. We are all keenly aware that beverage companies do not have a single source for their glass bottles. In fact, shipping costs of containers both empty & full quickly eat into profits. Therefore bottling plants are situated around the globe, usually utilizing glass container vendors that are close by, minimizing overall distribution costs - "make it, where it is drank." Eventually, all of these bottles get a soda label applied and they get filled with soda. Does that make the glass containers from these various vendors the same in their chemical composition? Does someone somehow think that the contents of the bottles in some way will make these bottle harmonious? Corona bottles for instance, used to have the element cobalt in the paint on the labels. Any cullet (ground up recycled glass) that contained any hint of Corona bottles was routinely refused by companies or processors that uses glass cullet (source: Container Recycling Alliance).

Some of the manufacturers claim that they have "special chemicals" that they add to make everything homogeneous. But they have a problem - the person who controls the source of their raw materials is the one verifying that the raw recycled glass is "all the same." But how can they tell by just looking at it? Unless they actually take in, clean, sort, & grind all of their own recycled glass containers there is absolutely no way to know 100% that the cullet is all the same!

Many name-brand tile companies here in the United States, actually have their tiles manufactured in China (by someone else). Most of them do not even own their own manufacturing facilities. Instead, they rely on these Chinese companies to make their tiles for them. They have virtually no control over the raw materials or the manufacturing process. It is merely accepted if it is delivered on time & it cosmetically looks correct. You can find these glass tile mosaics in almost every Home improvement store. In tiny print somewhere on the box it says "Made in China." They conveniently left off the rest of the disclaimer, "...by people who don't give a rats ass about you & only want your yankee dollars."

Lack of Quality Control
Most manufacturers do not perform any type of quality control, other than maybe a visual inspection with the naked eye as it passes down an assembly line. Some might have automated systems that check for consistency in size & thickness. They may even go to the extreme of using a computer to check the color of the finished glass tiles against a production standard.

But few if any are using a polariscope, to perform a visual inspection of a random sampling of the finished products. Some of the manufacturer's that I've talked to didn't even know what a polariscope was! How the hell can they even perform this crucial inspection step, if they don't even own one?

Polariscope
What the hell is a polariscope you say? Well, it is actually a relatively simple and very inexpensive device. The polariscope is an important tool for determining strain & stress patterns that develop during the manufacturing process. It allows an inspector to immediately determine if strain or stress is present in almost any transparent material.

How it works...
The polarizing filters align the light into planes of polarized light. When the polarized light passes through that area of stress, the light becomes retarded. The amount of retardation observed is directly proportional to the amount of stress in a given area. A polariscope is merely a device that transmits light through the translucent material (from behind). The inspector looks through 2 polarizing filters, while slowly turning one of them 360º to change the alignment of the planes of light. Any inherent stresses within the material will clearly highlight themselves. How obvious are these stresses within the material? Take a look for yourself - you be the judge:
Images courtesy of: yours truly

(Click on an image to enlarge it - again to shrink it).

The tile to the right has obvious stresses horizontally across the top as indicated by the white line. The clouding on in the bottom of the tile also indicates an area of stress.

The image to the right shows a large internal stress down the center of the tile. This will most definitely manifest itself as a fissure or crack. once the tile is exposed to any environmental thermal expansion.








This small 1" x 1" tile to the right shows a large area of inherent stress all across the top edge. To the unassisted eye under plain lighting conditions this looked like a perfectly good tile. The job that this batch of glass tile mosaics were installed in, had an installed failure rate of 25-30%.
Guess what percentage of unistalled tiles from this batch exhibited indications of internal stress? Good for you, you're so smart - about 30%! Coincidence? Hardly! Now since this was never installed, how can the manufacturer blame the installation?




The tile to the right is what a "good" piece of glass mosaic tile should look like under a polariscope.
The star actually "rotates" as the singular polarized filter is rotated. The small bubbles within the tile are acceptable, and should not affect it's performance.



So, how much do these complex testing apparatus cost? A measly $250-$1,500. At those prices there is absolutely no excuse for these multi-million dollar companies to not own at least one!

Tile showrooms, tile buyers, distributors, tile contractors, swimming pool contractors & designers, and "expert witnesses" should all own one... The industry needs to start rejecting these faulty defective materials, before these unscrupulous manufacturers get the opportunity to push the blame onto the "poor installer" one more time!

Come to think of it, I have never been asked by a glass tile factory to "send us a sample of some unmounted tiles, so we can test them." It has ALWAYS BEEN: "Something must have been done wrong in the installation..." WELL, THOSE DAYS ARE OVER! There is a smarter consumer emerging from the woods... and they are well armed (with a Polariscope)!

Imagine, receiving a shipment of glass mosaic tiles, soaking them in water to remove them from their facing paper, then inspecting a few square feet for these flaws. Then calling them up to come get their recycled crap off of your lawn (from the couch on the front porch, they're blocking your view of the pink flamingos).

The manufacturers will quickly change their ways, as the word got out that they are knowingly (or ignorantly) selling defective glass tiles. These defective tiles simply are not suitable for the purpose that they were advertised for!

We need the Consumer Product Safety Commission to get involved - maybe the Congress can do some good afterall!

Have you experienced a glass tile mosaic failure?
Go and buy yourself a polariscope - because the proof is IN the pudding glass!


Paolo Benedetti - Aquatic Artist, Designer, Consultant, Expert Witness
"Creating water as art."™
Aquatic Technology Pool & Spa
©www.aquatictechnology.com

Knife Edge Perimeter Overflow Pools - The Ultimate Perimeter Overflow Design

Internationally renown pool designer Paolo (Paul) Benedetti presents a new twist on the knife edge perimeter overflow pool - a 360 degree deck level vanishing edge! It might also be called a: no coping pool, zero edge pool, no edge pool, or edgeless pool. It is also known as the "Lautner Edge," named after the famous Los Angeles Architect, John Lautner, who conceived of the detail. However, my firm has refined the detail into a masonry knife edge!

These are not to be confused with horizon pools, gutter pools, waveless pools, grated overflow pools, perimeter overflow pools, slot overflow pools, flooded deck pools, slot edge pools, wet edge pools, vanishing edge, negative edge, infinity edge, disappearing edge pools,wetted edge, no edge, flooded coping pools, or wet deck pools, though they all provide essentially the same appearance... that the pool is overflowing.

The "knife edge" technique used on a perimeter overflow pool is the most complex of any of the edge techniques available. What makes this detail so unique, is that there is virtually no flooded coping or edge material... in essence, it is a "knife's edge." The water falls into a slot right at the top inside edge of the coping or decking material.

A Brilliant Mind

Los Angeles Architect John Lautner was one of the early pioneers of this technique. It first appeared on the Goldstein-Sheats residence in Beverly Hills. Though the detail was rudimentary, it is the inspiration for the watershapers of today.
The original detail utilized a
stainless steel gutter affixed to the concrete shell. The interior finish of the pool is bonded to the stainless steel.
(click on the image to enlarge it in a new window)

The inner wall of the stainless steel gutter mustn't flex or the pool's aggregate finish will delaminate. This necessitated the use of reinforcing ribs between the outer walls of the slot, which are visible from above. This detail also made the inside wall of the pool (at the slot) visibly thicker than that we use today.

One of the later watershapers to reintroduce the use of the Lautner Edge, was Brian VanBower of Miami, Florida. His knife edge detail also relies on the custom fabrication of a stainless steel gutter. Though my firm had previously used knife edges as a lesser detail on larger projects, we had always built them out of concrete & masonry. I have found that anytime you have to custom fabricate anything (especially stainless steel) it gets expensive FAST!

Refining the detail

The variations of the Lautner Edge that I have utilized have been both visible and hidden. I have utilized a raised exposed rim in order to create shallow layers of water or splash areas. I have utilized the "true" (though refined) Lautner Edge, in it's original concept - with the collection gutter hidden from view.

This design of mine from a few years ago, is an example of the utilization of both techniques on the same project. The elevated shallow area is created around the umbrella, by merely elevating the edge detail & allowing the water to spill over the top into a deck level slot.

(click on the image to enlarge it in a new window)

I later utilized a deck level version of this detail near some "floating steps" in the deep end of the pool. The use of various edge details on one pool, gives the viewer the illusion that the pool is "out of level." This use of forced perspective, tricks the eye into thinking that the pool is out of level. This is accomplished through the use of a regular tiled waterline and the use of a slot edge at the opposite end. A change in deck elevations allows for the mixed edge details, and facilitates the transition.
While this mixed use of edge details can be confusing, I added to the complexity of this project by adding 2 additional edge treatments... a standard vanishing edge (infinity edge) and a perimeter overflow spa.

(click on the image to enlarge it in a new window)

The spa has the illusion of spilling into the vanishing edge catch basin. But this is a definite no-no. For those who do not understand basic hydraulics - you need to go ask someone why!? A novice mistake for people who "talk the talk," but can't even "crawl the walk."


Evolution of an Idea

I saw some of the other international designers starting to design & build entire pools utilizing a custom fabricated stainless steel Lautner Edge. I saw this as an unnecessary waste of time, energy, and money. Problems arose when the dissimilar materials need to be "wed.' The interface between stainless steel & the concrete pool structure needed to be waterproof and absolutely solid. This oftentimes resulted in "overbuilding" of the stainless supports or gutter, in order to compensate for the unknowns.

I'd rather utilize what I know to has worked in the past, whenever possible. Why waste your energy and the added liability associated with inventing & building your own wheel?? Though we have been able to prove that we can bond glass & ceramic tile, granite and even plaster to stainless steel - why risk the chance when it can easily be avoided simply through the use of compatible materials?

I was called upon to design a pool for a local pool builder. Seems that he was under contract to build a conventional pool, when the landscape architect sold the property owner on the idea of a knife edge pool. He turned to me to resolve the design issues and to incorporate a concealed retractable pool cover into the floor of the spa (as unobtrusively as possible).

The finished product is gorgeous. It works with the site, as if the scene would be incomplete without it. This is what design is all about... it has to look as though it belongs!
(click on the image to enlarge it in a new window)


This is design perfection that John Lautner would be proud of!



Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa
©www.aquatictechnology.com