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!

Wednesday, December 29, 2010

Pool Finish & the Color of the Water

Internationally recognized infinity edge swimming pool designer Paolo Benedetti discusses the color of the pool finish and other the variables that affect the perceived color of the pool.

Most people who are having a swimming pool designed, almost always say "I want the pool finish to be blue, so that the water looks blue." And they hold to this hard and fast, though it couldn't be further from the truth.

There are actually many variables that affect the perceived color of a swimming pool, fountain or spa. Merely placing a blue finish onto the pool walls does not guarantee that the pool will appear blue.

Physics - something we cannot control
Physics is not something that we can just turn off, cover up, or demolish & haul away - it is here to stay & it is always ON.

Let's face it, water is clear - at least clean water is! And because it is clear, it does not assume the color of it's surroundings like a chameleon. But, water does do some interesting things to light.

It bends light, so that anything that is being viewed through the water, is not exactly where is appears... this is called refraction. Place a stick into some water... you'll observe that the stick appears to bend at the surface of the water.

Because light travels slower in water, objects under water will appear about 1/3 larger than they actually are. So now things will look bigger and not be exactly where they really are.

Light will also scatter as it passes through water. The deeper light travels through the water, the more of an affect the water has upon scattering the light. This is why objects lying on the bottom of a 20 foot deep pool seem to have lost their contrast.

Light is also absorbed as it passes through water, and it is lost rather quickly. In 2 holes of equal depth - one empty and one filled with water. The one with the water will be darker at the bottom. Scuba divers know this well.

Additionally, the various colors of the light spectrum are absorbed by the water at different rates. Some colors are just not as intense & are absorbed rather quickly, while others penetrate deeper into the water. This is is what has the greatest effect upon the colors that we think that we see underwater ("perceived color").

Red is the weakest of the color spectrum and it is filter out at rather shallow depths. Orange is lost next, followed by yellow, green, and then blue. A deep clean body of water will therefore appear blue when viewed from the proper distance & angle. The ocean or a lake can appear different shades of blue, green or brown due to suspended matter in the water that absorbs or reflects the various colors of the spectrum.

So how do we predict what color a viewer will perceive? We use basic color theory...

Color Theory

Shallow water does not have much effect upon filtering out the red & orange light spectrums. This explains why a pool appears to be bluer in the deep end.... the red light is being filtered out and the blue light is continuing to the floor of the pool.

So, this blue light will reflect back at the viewer along with the color of the pool finish. So a brown or tan finish (yellow spectrum)in the pool, when combined with the blue light will make the deep end appear green (yellow + blue = green). By contrast if the pool had a red finish, the pool would appear red in the shallow end, but in the deep end it would appear violet (red + blue = violet).

The Sky

If the sky is bright blue, that color will be transmitted to the pool. By contrast, if the sky is cloudy, orange, etc, those same colors will be transmitted into the water. So a pool at sunset on the ocean will appear much different than a pool in the snow covered mountains or a cloudy day.

View Angle

Looking down onto a pool from a high rise hotel is the best example of "view angle." The viewer is able to take in the entire scene, deep and shallow end together, and not be affected by glare upon the water.

The closer the viewer is to the surface of the water, the more apt they are to be affected by reflected light (oftentimes called "glare" if it is sunny outside). This surface refection and the refraction of the light exiting the pool, does not allow the viewer to see the true effects of this phenomenom of the combination of colors.

Proximity to the Pool

If the viewer is close to the pool's edge, the perceived colors will be different than if they were observing the pool from overhead. Additionally, our eyes automatically focus and try to "see the bottom" of the pool, so we cannot effectively absorb the colors that are presented. As we begin to distance ourselves from the pool, our eyes focus less on the details and more on the scene. This is the point where we begin to observe the blending of light and materials.


Objects in the immediate vicinity of the swimming pool also contribute color to the water. Tall buildings, trees, shrubs, retaining walls and decking all contribute their own color to the scene & water. Items that are reflected upon the surface of the pool also change the perceived color.


If it is important to you to achieve a certain color, then it is best to hire someone who has had some training in color theory and who possesses the knowledge to manipulate the project to achieve your goals.

Because there are so many contributing factors - many that are variable & in a constant state of flux, this is really more of an art than a science.

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

Monday, October 25, 2010

Beverly Hills swimming pool designer Paolo Benedetti discusses the importance of using white thinset

Paolo Benedetti, an internationally renown Beverly Hills swimming pool designer, builder of infinity, vanishing, and disappearing edge pools discusses the importance of creating installation mock-ups and of using the correct materials when setting tile & stone.

Backing Color
Since most glass tiles are somewhat translucent, it is imperative that the surface behind the tiles be white. This means that waterproofing systems, thinsets, mortar beds, basically anything in contact with the reverse of the tiles.

Most membranes are colors other than white. Most are of colors that owners do not want to see: blue, red, black, green. Since tiles can vary slightly in their thickness, it is important that there be a layer of something white on top of the membrane. This can be as simple as placing a skim coat of a white thinset on the membrane before installing the actual setting bed of thinset.

Installers usually tap the surface of the tiles to ensure complete embediment into the setting bed. The thicker tiles will embed deeper than the thinner tiles. This will displace more thinset than the thinner tiles... resulting in a thinner layer of thinset below the thicker tiles. A colored membrane may show through this thinner layer a little more than the thicker layer below the thinner tiles.

Thinset - Gray or White??
I just explained why white behind lighter colored glass tile is so important. So the answer should be obvious... WHITE THINSET under light colored tiles, GRAY under dark colored tiles.

Glass tiles come in all formats, opaque, translucent, clear, integral color, and colored back coatings or any combination of the above. Light colored tiles will provide a true color rendition when white thinset is used.

When setting clear tiles, you should always create some mock-up sample boards. I know there is an additional expense and related time delays, but a few days spent here will save you a lot of agony in the future (and the expense of tearing out tile & starting over). You might not be satisfied with the color rendition when a gray background is used.

Grouts will also change the color of the tile. Since the grout is worked in between the tiles, it will impart a hue within the glass. A dark grout will darken the color of the tiles, while a lighter will brighten it.

However, using a white grout with dark colored tiles will make the surface look like a giant crossword puzzle. So it is best to select a grout color that is close in color to the tiles. This is most important for clear or opaque tiles, that will "read" the color of the grout.

Be sure to soak the grouted sample board underwater for a period of time prior to making your selection. After being underwater for sometime, the grout will absorb water. This saturation will darken the color of the grout. grout underwater will be darker, while the grout above water will be lighter. So - be sure to wait for the grout to absorb some water before making your choice in grout color!

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

Sunday, August 29, 2010

Glass Tile Fracture & Failure - Glass Tile Mosaics, Cement and Alkali Silica Reaction

Paolo (Paul) Benedetti founder of Aquatic Technology Pool and Spa, an internationally recognized aquatic and water feature designer and builder discusses the failure of glass mosaic tiles... simply due to the installer's failure to read and follow the installation directions. His vanishing edge, infinity edge, knife edge, and perimeter overflow pools grace some of the most sophisticated estates in the world.

Read the Instructions BEFORE you have problems...

Failing to precisely follow the installation instructions for glass mosaic tiles can result in a catastrophic failure of the tiles or specialty coatings. Most men have an aversion to reading instructions or taking advice. Let's face it, it's a guy thing... whether it be a road map (before we get lost) or the assembly instructions for that new kid's bicycle on Christmas morning (before we curse and swear Santa and the Elves for not bringing it fully assembled!).

The Manufacturer's include Directions for a reason...

I recently reviewed an installation where the glass tiles seemed to be disintegrating right before the owner's eyes. The grout in some areas of the installation was intact & beautiful. In other areas of the installation (and coincidentally around the failing tiles), the grout appeared to be forming a white gel like coating on the surface. I immediately knew what was happening, but now had to determine WHY. Perfectly good tile was being destroyed by a shoddy installation.

The tiles in the above pictures were not subject to saturation from the fountain, and therefore the ASR had not formed (yet). Click on the image to see a larger view.

In the above image, you can clearly see the white gelatinous material forming between the tiles... almost like a white slime. Click on the image to see a larger view.

Alkali Silica Reactivity (ASR)

Alkali Silica Reactivity (ASR) is nothing new. The phenomenon has been around for centuries. It is based in science & chemistry. To explain it in simple terms, when high alkali cements are exposed to silica (a basic element in glass), the cement will turn gelatinous.

This gelatinous material expands as it forms, causing the cement to crack. Certain colors of glass can actually accelerate this reaction. The finer the particles of glass within the cement, the more severe the reaction. This is a real concern where ground glass is added to cement as an aggregate (recycling) or for decorative reasons (sparkles in the glass).

The ancient Romans used to add pozzolans (volcanic ash) to their cements to help prevent this from occurring. I doubt that they knew why it worked, but it did. Today, there are chemicals & other additives that can be incorporated into the cement to prevent this from occurring. Lithium, metakaolin (produced from kaolin clay), and fly ash are all used in different applications to control and prevent ASR.

Where the wheels fell off...

The tile in this case was from a quality source... Sicis. I have used Sicis in the past & continue to use their materials. I have found them to be first rate, and I do not intend to insinuate that the product is inferior in any way. The problem here, is that the installer created a chemical reaction that could be created with ANY brand of glass tile.

As with any material, you have to follow the installation directions. The installation instructions from the material manufacturer ALWAYS takes president over any other published standard or guidelines. After all, the manufacturer knows best, as to what works with their products.

After talking to the property owner & their installer, I quickly realized that the installer had relied upon what I have previously referred to as a set of the "daddy-dids" standards. He installed the tile the way his "daddy dids it," "the way I always have." However, had he bothered to read the instructions from the tile manufacturer, he would have clearly seen a large warning in the instructions. He had added calcium to the leveling bed, in order to accelerate the hardening, and therefore allow him to set the tile quicker (after all time is money, right??).

The instructions clearly state to avoid using high alkali cements & products where the tiles will be exposed to high levels of humidity (moisture). In a fountain or swimming pool, do you think that the humidity level is high??? Like maybe 100% !!!??? His addition of calcium to the mortar and failure to install a waterproof membrane accelerated the demise of this project.

Click on the above document to open a larger version for review. Under the left column "Laying & Sealing" heading, the second paragraph clearly states "adhesives containing alkaline-earthy hydrates (e.g.,. calcium carbonate) should not be used..."

Hiring quality installers

This is another example of the old adage... "You get what you pay for." Just because someone is a tile installer, does not mean that he is a glass tile installer. Glass tile installations take a special set of skills & knowledge. The installers that I know & use, have been installing glass tiles for decades. They have a intimate knowledge of the various standards that they must adhere to (TCNA, ANSI 108.5, etc.).

The best installers know what questions to ask, create mock-ups for testing & for the client to approve, and most importantly - they read the directions from the tile manufacturer. They use the recommended setting materials, and even read the directions of those products.

Documentation is also important in glass tile installations. Keeping track of when certain areas were floated, set, & grouted ensures that the proper curing times were adhered to.

Tracking & recording the production lots of the various setting materials used, also allows for "reverse engineering" and a linear accountability in the even of any issues of this sort. And of course, tons of pictures. Digital images are free, so there is no excuse to not take thousands of them!

The only means to correct this failing installation, is to strip the entire job and start over. Where's the money savings now??

In this close up image, not only is the ASR gelatinous growth visible, but the additional calcium (lime) is bleeding out of the grout joints. Click on the image to see a larger view.

Hire quality designers, craftsmen and specifiers and you'll actually save yourself a lot of heart aches and money in the long run!

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

Friday, July 16, 2010

The very first infinity edge, vanishing edge, perimeter overflow, and knife edge pools

Internationally renown aquatic designer and builder, Paolo Benedetti, discusses the history of infinity and vanishing edge swimming pools, throughout the ages.

There have been a lot of charlatans in the pool industry who have claimed to have created the "very first" vanishing edge pool (aka: disappearing edge, infinity edge, zero edge). However, those that claim to have designed or built the very first of such effects are either ignorant or possess "an inflated value of self worth" (fat egos and are blatant liars)!


By simply looking at the horizon when at the beach, one can view the oldest of all of the disappearing water on horizon effects. Standing above a waterfall, one can again see the simple effects of "water on the horizon." The largest series of cascading "vanishing edge pools" ever created, was also created by Mother Nature at Pamukkale, Turkey.

Click on the image to see a larger/close-up view.

These effects were created by GOD... no mortal can lay claim to creating these effects. Period.


Throughout history, builders have borrowed on their observations of these naturally occurring water on horizon effects. They have incorporated these effects in the fountains or pools that they built. One of the earliest forms of zero edge fountains were overflowing pots or bowl fountains. By providing them with a constant supply water, the bowls merely overflow their rims. This kept them clean and clear while creating the effect.

This effect was used as far back as the Romans. Water from rivers & streams was diverted for use in the fountains, homes, and agriculture, then allowed to flow back into the river.

One of the lesser known fountains of Versailles, the Stag fountain, has an inverted vanishing edge. By inverted, I mean that the water flows over a weir (edge) towards the viewer. This fountain dates back to the 17th Century.

Click on the image to see a larger/close-up view.

As I have discussed in an earlier posting (, Los Angeles architect John Lautner (1911-1994) was the modern pioneer of the vanishing edge pool. He incorporated variations of vanishing edge pools in many of his projects.

Completed in 1963, Silvertop, in Silver Lake, CA was Lautner's first true vanishing edge pools. Construction started in 1957, so he must have conceived of the idea at least 4-5 years prior (1952?). This was way before any of the geniuses in the swimming pool industry had ever heard of the term "vanishing edge pool."

Click on the image to see a larger/close-up view.

One of his lesser known projects, the Aranjo House, is situated in the hills above the Acapulco, Mexico harbor.

Click on an image to see a larger/close-up view.

Though this was not a vanishing edge in the pure sense of the term, it illustrates that water as an architectural element was being utilized to create a water on the horizon effect.

Another of John Lautner's famous edge pools is the Sheats-Goldstein house. This pool was not originally a knife edge perimeter overflow pool. It was retrofitted with a stainless steel slot gutter by the current owner, James Goldstein.

Click on an image to see a larger/close-up view.

The only true innovation of recent history was the invention of the deck level perimeter overflow. It is a variation of a competition swimming pool gutter design. Instead of being placed into the interior of the pool, the gutter is placed upon the top of the deck.

While setting a trend, the effect is unrefined and it's approach amateurish at best. It is oftentimes utilized on commercial pools, as it is easy to install and maintain. However it is unsightly.

Though someone falsely may claim to have designed or built the very first vanishing edge swimming pool, a simple look back through history clearly reveals their deceit.

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

Friday, June 18, 2010

Aquatic Technology & Paolo Benedetti receive World Class Architect's Praise

A World-Class Pritzker Prize winning Architect that I had the privilege of working with a few years ago posted the following comments about my involvement on the project:

"I have worked with Paolo Benedetti on a large multi-million dollar project. He was ALWAYS looking out for the client's best interest. When he observed trades (outside of his area of control) performing substandard work, he would bring it to my attention (as the Project Architect). He would have always done his "homework," so he was not "speaking out of school."

I found that this made it easy to make corrections & to "educate" the trades people performing the work. In a few cases, we even changed our installation specifications.

As a member of a large estate "build out" and design team, he made some very creative suggestions for other areas of the projects. Ideas that I am surely would have never been presented, let alone thought of. He quickly became a integral & valued member of the design team.

If you are shopping for contractors by soliciting bids, then he is not the designer/contractor for you. He brings much more value & knowledge to a project, than what can be reduced to dollars & cents.

If he ever showed the interest in being an "Owner's Representative" for an estate build-out project, he'd be on my short list. He is a true artist, with a detailed eye, knowledgeable on multiple trade's practices, and a stickler for doing things the right way (which is not always the easiest way!).

Because he is a General Contractor and a Swimming Pool Contractor, we used his firm to install an indoor "spa room" and water features, and to consult with indoor waterproofing practices. He also build the outdoor living spaces, pools, spas, fountains, fireplaces & outdoor kitchen areas.

My firm had already designed the entire estate (buildings, grounds, & swimming pools), when Paolo was brought into the project by the client. Paolo was tactful when making suggestions about changes to the design. Though I was reluctant at first, he made a number of observations (about the site & client's lifestyle) that warranted a TOTAL REDESIGN of the pool area.

We prepared our own concepts, had he fallen flat on his face. But much to my surprise, his concept presentation fit perfectly with the architecture of the buildings. AND, he stayed true to the theme of the estate/project. I endorsed his concepts and let him play out his plan.

In the end, it was a WIN-WIN for the client. I learned a lot about swimming pools, their proper design and construction.

I also came to the realization that there is truth to the saying, "you get what you (are willing to) pay for." I never knew that there were artisans in the swimming pool industry that cares so much about what they do. He really took pride in everything that he touched.

The client could not stop singing his praises. And, I will definitely utilize his services when my firm is called upon to design another outdoor living area and/or swimming pools."

So what are you waiting for... call me @ (408) 776-8220 and schedule your initial consultation.

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

Tuesday, June 15, 2010

Glass tile mosaics - tessellated stress cracks fissures microstresses

Recycled glass: Bad for glass tile, but good for the environment (and manufacturer's profits)!

Tessellated stresses and microstresses (cracking & stress fissures) within glass tile mosaics that contain recycled glass as a portion of it's formulation, are problems that many tile mosaic manufacturers simply do not understand. Most are not even willing to subject their tiles to any thermal shock performance testing. They bury their heads into the sand.. hoping that the problem will go away. It won't... (and I won't!).

If the manufacturer's never test their tiles for thermal expansion stress cracking, then they can continue to "play dumb." This allows them to "blame" the installation, because they know that it will be difficult & costly for an installer or property owner prove that there are materials or manufacturing issues. However, the underlying problem actual lies in their manufacturing process & the improper mixing of dissimilar materials.

With so many companies jumping on the environmentally "green" bandwagon, many are manufacturing products that are not durable. They simply do not understand material science and physics.

It will only take an Act of Congress, Consumer Product Safety Commission, a State Attorney General or a Class-Action Lawsuit to enforce minimum quality & performance standards upon these manufacturers.

Lack of Quality Control & Education

Almost all of the manufacturers fail to understand the importance of a homogeneous mix of virgin materials with the recycled materials. The recycled materials must be mixed thoroughly with themselves and with any additives or raw materials that are added.

If there are portions of the batch that are not homogeneous, there will exist a differential blend of material throughout the finished product. The laws of Physics dictate that different materials have different rates of thermal expansion.

Because these different materials expand at ever-so-slightly different rates, and because glass is not elastic, this stress will cause stress cracking or fissures.

Inconsistent Temperatures

Adding to the problem, is another law of physics. Thermal expansion occurs within matter at a rate in proportion to the temperature. In an installed application there exist temperature gradients throughout glass tile. The surface is heated or cooled at a rate that is faster than the back of the material.

Remember: the back of the material is usually mounted against a cool concrete structure. When the surface of the glass is exposed to the sunlight or swimming pool, it heats up at a faster rate than the back of the tile.

This "temperature gradient" can cause cracking within the tiles. Coupled with the use of recycled materials, and you have the formulation for failure.

Material Size and Thickness

We've established that there can be a temperature gradient within a singular tile. Physics also dictates that thicker tiles will have greater degrees of temperature gradient than thinner tiles, from top to bottom.

Stresses will be less likely to occur in smaller format tiles (1x1's) than in larger format tiles (3x3's, 4x4's, 6x6's +). Irregular sizes (rectangles, triangles, circles, etc.) can also create unusual stresses within the glass tile. This is not to say that they will not occur in small tiles - they do. Given that a small tile may crack, it is almost guaranteed that larger formats of the same tile will crack.

This occurs because the edges remain cooler than the center, creating gradient temperatures across a larger surface area. On a smaller tile, the gradient is less as the core is closer to the edges.

Thicker tiles also contribute to the gradient temperature issue, as thicker tiles cause "shading" of neighboring tiles, allowing the sides & edges to remain cooler than the core or surfaces.

Add coatings to the glass, and you have further altered the possible temperature gradients, by absorbing or reflecting heat in an irregular fashion.

Unknown Raw Materials

Just because a manufacturer receives all of their "raw recycled glass" from one source, does not automatically mean that it is all the same. If a manufacturer uses only recycled soda bottles from one brand of soda - there is no way on God's Green Earth that they can be 1000% certain that all of the bottles are EXACTLY the same.

The soda bottle manufacturer may change formulations ever so slightly from batch to batch, manufacturing temperatures may vary slightly, or even their raw minerals or suppliers may vary slightly.

Since most manufacturer's rely on the "say so" of their supplier to verify that all of the bottles are the same, there is another source of doubt as to the "quality" of the recycled glass. Because the recycled glass is already ground up (aka: "cullet"), there is no means to test the glass to verify the veracity of their claims. It could have soda bottles, old windows, automobile glass (argh!!!), beer bottles, food jars, or contain labeling contaminates such as cobalt (like is found on Corona bottles).

If there is the slightest piece of heat-resistant glass like Pyrex or borosilicate glass present in the cullet, it will alter the viscosity of the fluid in the furnace when it is remelted.

Add to the variance equation, the fact that there may be multiple suppliers of soda bottles to the bottler - each with their own formulation & raw material suppliers, and you have sufficient material variances to wreak havoc with the performance of glass mosaic tiles.

The recycled glass association's standards allow variances in the cullet mix, proof again that there are contaminates and variables in the "raw recycled glass." Here are their acceptable standards:


Composition: Soda-lime-silica container glass.
Container Glass Cullet Colors Segregation: Flint Cullet
Flint 95-100%
Amber 0-5%
Green 0-1%
Other Colors 0-.5%
Total NON-Flint Cullet = <5%>Size: Various sizes from whole glass containers to -100 Mesh.
However, the ideal material size is 3/8" to 3/4" with a 10% minimum
of fine particles. Material size is based upon buyer and
seller's agreement.
Contaminant Listings:
Outthrow Materials: Organic Matter, allowable percentage
based upon buyer and seller's agreement.
Prohibitive Materials:
Ferrous Metals
Nonferrous Metals
Ceramics (such as cups, saucers, dinnerware, pottery, etc.)
Other Glass (for example, plate window glass, heat-resistant
glass—such as Pyrex—and lead-based glass—such as
crystal ware, television tubes, vision ware, etc.)
Other Materials (such as bricks, rocks, etc.)"

Unpredictable Results

Most of the models for predicting the performance characteristics of glass formulation rely on multiple regression analysis or by additivity equations. But the primary principle for utilizing these mathematical predictions, is that you know the formulation of ALL of the raw materials - totally impossible when using recycled glass!

As with any quality control procedure, these equations are the same: garbage in, garbage out. Since they cannot possibly ascertain the chemical composition of 100% of the recycled glass cullet, they are forced to either "guesstimate" or use a random sample of the cullet (and assume that it is all the same!). This is where the variability begins... right on the loading dock!

Why so Random?

Because the materials are not thoroughly mixed, it reasons that there are areas of the sheet of glass, wherein there exists higher concentrations of heterogeneous material. Because the mixing may be more thorough in one batch than the next, concentrations throughout the glass may vary, and tiles may be mixed with other batches of the same color, the resultant cracking in tiles will appear to be totally random.

It may not occur in every color or size of the same tiles. It may appear in adjacent tiles or they may appear in isolated tiles. But there is often a major commonality... the cracking is not linear. Tesselated stresses may transfer into an adjacent tile.

However, if the cracks are directly in line with each other and through a minimum of 3 tiles, then thermal stresses are probably not the cause. Linear cracking through multiple (3+) tiles is probably the result of substrate flexing or movement. This is not to say that tesselated stresses can not coincidentally align across 3 tiles. But there is a statistical probability of this occurring in 2 adjacent tiles, so 3+ has become the rule of thumb.

If the cracks are not through the entire tile, then there is a high probability that it is not installation related. This is "clearly visible" on clear tiles - if they look like fissures within an ice cube, then they are probably thermal stress cracks.

Remember, the larger the format of tile, the lower the tolerance for substrate movement & the greater the chance of thermal stress cracking. The problem is compounding itself!! Example: A lot of grout joints in 1x1 mosaic tiles across an area are a lot more forgiving than rigid 12x12 tiles!

Getting it Mixed Right

There are a few approved methods to ensure that recycled glass is utilized correctly. However, it requires that the glass formulation is mixed thoroughly.

One method is to actually mix the molten glass with a mixer, something that is difficulty, costly & dangerous. Most manufacturers utilize linear kilns - a conveyor belt within a long furnace. This makes mixing molten glass in this method impossible.

The second method, involves multiple stages & involves grinding the glass multiple times. First the recycled glass is ground as small as possible (cullet). The finer it is ground, the more thoroughly the blend can be mixed. Virgin materials are mixed into the mixer along with the ground recycled glass. This mix is then fired into glass utilizing a linear kiln.

Unfortunately, this is where most manufacturer's end their processing. They form their tiles and ship them out the door.

To ensure that the various glass formulations are thoroughly blended, there are two more stages of processing required.

To ensure a thorough homogeneous blend, the glass that is made during the first stage above, is process again. It is broken up & ground up as fine as possible. This fine pulverized glass is again thoroughly mixed. Now it can be fired and made into consumer ready glass mosaic tiles.

Ensuring that there is a homogeneous mix entails additional processing and a double firing of the glass, which is costly. The production time, energy and labor costs more than double! Therefore, most manufacturers who utilize recycled glass merely skip this step.

Some manufacturer's add chemical that they claim solve the issue of homogeneous blending. However, it is statically impossible to prove that the end result will be a homogeneous and isotropic blend. And since there is a very high probability that the cullet is contaminated, there is no means to chemically treat for all possible variations - Who's fooling who???

Principals Founded in Physics & Material Sciences

These are not my hypothesis or mere suppositions... something that I made up.

These are facts based upon over 100 hundreds of years of the investigation of physics & material sciences. In fact, the phenomenon of glass stress cracking from non-homogeneous blending was discussed in scientific papers as far back as the 1890's! Many organizations have investigated this phenomenon:

National Institute of Standards and Technology
Corning Glass Works
The American Ceramic Society
International Symposium on Glass Problems
and countless foreign entities.

The Lack of Standards & Differential Expansion

The development of tessellated stresses in glass tiles that utilize recycled material will continue to occur, until manufacturers are held to some standard for thermal shock performance.

If they subject their tiles to the CTIOA (Ceramic Tile Institute of America) thermal shock testing (who's tests are designed for ceramic tiles - which do not apply to the performance testing of glass tiles), they only have to submit a mere 5 tiles for testing.
This is not a representative sample of the tile's performance. Again - simple statistical analysis...

Nor is allowing the testing of ONE size of each product line, representative of the entire products line's performance. Glass of different colors contain different chemicals and formulations, and glass tiles of different sizes perform differently. Given their choice, the manufacturer's will submit clear glass 1X1 tiles, who tests will then be proffered as representative of an entire product line.

Manufacturer's are not required to re-certify or submit subsequent production lots for verification of continued compliance and quality control. As the recycled glass (raw materials) change from day to day, so will the final product's performance - yet they will still be relying upon those initial test results.

The CTIOA testing also tests the tiles in their "loose" unmounted state. Now who buys tiles to throw them loose into a pool? They should be tested in their mounted condition, with approved setting materials. Yes, multiple variables & various manufacturers. At least they'd have testing data for compatible setting materials.

Currently there are no performance standards for glass tiles.

It truly is the...

"Wild Wild West!"

"Buyer Beware!!!"

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

Pitfalls of Owner Supplied Materials

Many owners believe that they are saving money by supplying materials to a design or construction firm, and then only paying for the installation labor and materials. However, this is a very myopic and narrow view of the entire "what can go wrong" scenario.

Material Warranty
First of all let's get something straight right now... there ISN'T ONE! Nada, bumpkiss, zero, ziltch, squat...

Since the installer was was not the specifier, they are not responsible for any of the myriad of failures that occur with materials. When there are material failures, the homeowner is not going to say, "golly gee, the deal on that cheap material wasn't such a great deal afterall." I have consulted in many of these situations, and the homeowner response is very predictable. IT ALWAYS IS "they must have done something wrong during the installation to cause this..."

Because the homeowner is not an expert in construction materials or the particular application where they are to be used, they do not know the particular questions to ask when sourcing materials. Just because the vendor says "it's fine for that use," does not mean that it is! Just because you saw the same (or a similar looking material) used for a particular purpose, does not mean that it is! Just because you saw a material that looks just like it (used this way), does not mean that it is (the same material)!

Sourcing materials is a science in and of itself. Below is a short list of things to consider (and not even close to being inclusive of all of my selection criteria):
Freeze/Thaw Climate
Material composition (chemical make-up)
Reactivity of the material with the environment (snow, rain, swimming pool chemicals, wind, sun, heat)
Material Offcast (will the material bleed minerals or decay when subject to the environmental influences - above)
Hardness (is the material hard enough & durable enough for the purpose)
Porosity & Stain Resistance (will it resist staining from common materials)
Heat Retention (important in the dessert/tropical areas)
Slip Resistance (polished materials are not always the slipperiest!)
Available Finishes
Component Sizes & Thicknesses
Workability (how hard is it to fabricate & install)
Installation Specifications (does the supplier provide them?)
Who's going to create the mock-ups?

So, do you really still want to source your own materials to save some money on the specifier/installer mark-up?

Installation Warranty
The only warranty provided for the installation of any owner's supplied materials, is that they won't come loose or fall off (unless the material falls apart). PERIOD.

So, do you really still want to source your own materials to save some money on the specifier/installer mark-up?

Repairing Material Failures
Guess what - any cost associated with any of these repairs is the homeowners responsibility also! Most homeowners are so embarrassed that they were "penny wise & pound foolish," they will argue to the death about reimbursing the installer for these related repairs. Most installers will require payment in advance for these type of repairs (to the maximum allowable legal limits).

No one wants to perform any repairs to someone else's substandard materials, to get shafted for the payment after making corrections - and it happens all the time. It's one of the oldest homeowners scams in the book...

This is the largest cause of litigation in the area of construction warranties and workmanship. So put it all in writing- any repair or modifications to ANY owner supplied materials will be performed on a predefined "time and materials" basis - and don't forget the contractor is entitled to include profit in these rates too [because they're there - they're not working somewhere else making a profit (it's called "opportunity cost")]. Pay the contractor at the end of EVERY day, for the repair work that they performed.... it limits everyone's exposure!

So, do you really still want to source your own materials to save some money on the specifier/installer mark-up?

Installation Specifications
Does the vendor of the materials provide DETAILED installation instructions and specifications for any setting/finish materials? If they do not provide such details, then who is going to research & specify the methods and materials to be used? If those methods fail, then who is going to be responsible? Will the manufacturer or vendor approve the use of the material for the intended purpose (e.g. submerged underwater, subject to the high temperature steam in a steam bath, exposed to temperature variables or direct sunlight, etc.)?

There are standards for establishing the proper substrate (backing surface) and rigidity for the installation of almost every type of stone or tile imaginable. There are specifications that cover masonry walls, wooden floors, concrete floors, building facades, sheetrock walls, counter tops, and so on.

What about crack control, uncoupling, and waterproofing membranes? What about movement joints & their placement?

So, do you really still want to source your own materials to save some money on the specifier/installer mark-up?

Installation & Setting Materials
Not all setting materials and methods are the same. In the days of old, masons & tile setters used to "site mix" various home brews of setting materials. A little of this, a little of that, etc....

With the high cost of labor & finish materials, there is just too much liability involved to install things that way. If the concrete cracks or the walls settles, what will prevent those cracks from migrating through the finish veneer?

Yet the available "homeowners grade" setting materials at most warehouse home improvement stores are not the best available. They might be from the same vendor or manufacturer the pros use, but almost every manufacturers reserves a few higher end product lines exclusively for the professional's use. This is usually due to the idiosyncrasies of these products and the additional skills required to install them: reading instructions, working quickly & effectively, installing them properly, and using them for the correct application.

The density of a material is very important when selecting an attachment method on a vertical or overhead area. A slab of granite or veneered wall of stone falling onto someone will ruin their day.

Are expensive specialized stone epoxies or mechanical clip systems to be utilized? Who shall perform the sheer testing or provide the standards?

Does the manufacturer of the setting materials offer a warranty on their products? Some offer a warranty if you stay with a "single source" vendor throughout the project. This is a great idea, as it also ensures product compatibility - that the setting material from one vendor does not degrade a component from another. Add to the confusion multiple vendors pointing their "blame fingers" at each other if there are any issues.

So, do you really still want to source your own materials to save some money on the specifier/installer mark-up?

If the designer or contractor specifies and provides ALL of the finish materials, setting materials, and labor - then guess what?

They assume the responsibility for any failures with the material and or the installation (unless there are manufacturing defects - like those that occur in the manufacturing of glass mosaic tiles that contain recycled materials).

So, do you really still want to source your own materials to save some money on the specifier/installer mark-up?

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

Saturday, January 30, 2010

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:

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)*:

*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.


...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

Friday, January 29, 2010

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!

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.

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, " 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?

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

Sunday, January 17, 2010

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