Tech Talk – April 2018

Thin gauged porcelain tile – North American research, collaboration, and standardization

By Bill Griese, Director of Standards Development, Tile Council of North America and Noah Chitty, Director of Technical Services, Crossville Inc.

In February, TCNA’s Bill Griese and Crossville’s Noah Chitty traveled to Castellón, Spain, to lecture to the Congress of Qualicer 2018 on research and standardization of thin gauged porcelain tiles and tile panels (GPTP) in North America. Following are highlights of their white paper on this subject, which was presented at Qualicer 2018. The paper, in its entirety with works cited, is available online at

ANSI A 137.3 and ANSI A108.19


In 2017, the North American tile industry released two new standards: ANSI A137.3, American National Standard Specifications for Gauged Porcelain Tiles and Gauged Porcelain Tile Panels/Slabs, and its companion, ANSI A108.19, Interior Installation of Gauged Porcelain Tiles and Gauged Porcelain Tile Panels/Slabs by the Thin-Bed Method bonded with Modified Dry-Set Cement Mortar or Improved Modified Dry-Set Cement Mortar. These standards, developed for the benefit of all tile consumers, are the result of a multi-year research and consensus process of the ANSI Accredited A108 Standards Committee, which includes participants from all industry sectors. 

These efforts aimed to establish a framework for specifications of products that are intentionally “gauged” to a specific thickness. Currently two classes of gauged tile products are defined by the standards: 

Those for wall applications from 3.5mm to 4.9mm and 

Those for floor and wall applications, from 5.0mm to 6.5mm. 

Other products, which either fall outside of these ranges or for which the manufacturer has not specifically provided a gauged-thickness designation, continue to be standardized under traditional tile specifications.

Terminology and strength criteria

One of the earliest topics on which the North American industry debated was terminology. These products were called “thin” tile, but since the same technologies are also used to create thick tiles – and end-users had increasingly prioritized tile thickness as a key characteristic – a new moniker was needed. Hence, the term “gauged” was born, basing the term on one used for other construction products – such as electrical wire and sheet metal – which carry different load capabilities and usage parameters across a variety of gauges. The group agreed to further differentiate gauged products based on their size, with gauged tiles being less than a square meter and gauged tile panels/slabs being greater than or equal to one square meter. 

In developing product performance criteria, the first key concern was breaking strength, as the North American requirement for traditional tiles was 250 lbf. Initially, very few – if any – thin gauged products met the requirement. Therefore, installed strength became the key to achieving performance levels comparable to those of traditional tiles whose exceedingly high breaking strength could often make up for flaws in mortar coverage or quality. With thin gauged tiles, though, the group chose to scrutinize how lower breaking strength may be offset by installation rigidity and increased mortar coverage.

Key provisions of the installation standard

To develop ANSI A108.19 Interior Installation of Gauged Porcelain Tiles and Gauged Porcelain Tile Panels/Slabs by the Thin-Bed Method bonded with Modified Dry-Set Cement Mortar or Improved Modified Dry-Set Cement Mortar, a group of installers, architects, and manufacturers conducted countless experiments to discover application and embedding techniques that make possible maximum mortar coverage, particularly for tile panels/slabs. Through these experiments, standard setting procedures for gauged porcelain tiles and tile panels/slabs were developed that facilitate optimal workmanship and system integrity. 

Mortar application: It was determined that applying a layer of mortar to both the back of the panel/slab and the substrate would result in the necessary bond coat thickness of 3/16” (4.8mm) and would allow for full encapsulation of lippage control systems. Anything less than this method would result in an embedded mortar layer thickness that was insufficient to achieve the agreed-upon substrate tolerance of a maximum deviation of 1/8” in 10 horizontal feet (3mm in 3m) from the required plane when measured from the high points in the surface for floors.

Mortar properties: Mortar properties such as extended open time, flow to achieve coverage, and curing parameters appropriate to the application, as well as a requirement for suitable mortar identification through consultation with the tile and setting material manufacturer are specified in the standard. 

Trowels: Only Euro-trowel, Flow-Ridge trowel, and Superior notch trowel can facilitate ridge collapse without the need to press and slide the tile. The group agreed to standardize the use of such trowels.

Embedding procedures: For floors, physically walking on the surface in the following pattern produces the greatest supporting mortar coverage: 

1) walk down the centerline of the tile; 

2) take small shuffling steps left and right from center to push air toward the edges.

This standardized procedure is listed in ANSI A108.19 for embedding tile panels/slabs on floors. For walls, a vibration tool and weighted beat-in paddle are specified in order to achieve optimal coverage.

For walls and floors, a vibrational tool used at the perimeter, achieved full coverage on the edge, critical for overall durability in flooring applications, and also facilitated full encapsulation of lippage control systems. For these reasons, edge coverage achieved through vibration is a provision of ANSI A108.19. The standard minimum required coverage is 80% for walls and 85% for floors. Additionally, maximum void size was established as 2 square inches (1290 square mm).

Coverage calculation: A standardized evaluation to calculate coverage was developed. ANSI A108.19 states, “In any single square foot under the embedded tile, coverage… is calculated by measuring the voids and the marked off square foot and dividing by 144 square inches (929 square cm) where the dry set mortar is not in full contact from the back of the tile to the substrate.”

Substrates: Standardized suitable substrates for the installation of gauged porcelain tiles and tile panels/slabs are mostly consistent with those of traditional tile, with the exception of direct bonding to plywood floors, which requires the use of a mortar bed or specified backer board and referencing floor rigidity requirements established by building codes and other widespread industry specifications. 

Applicable to all substrates, ANSI A108.19 details required flatness as maximum deviation of 1/8” over 10’ (3mm in 3m) from the required plane when measured from the high points in the surface.

Material handling: Qualified labor and other provisions also taken into account through discussion and A108.19 standardization were adequate jobsite storage, space to maneuver panels, prevention of damage while handling and time for mortar curing. Another critical aspect of ANSI A108.19 involves usage of properly qualified installers who are equipped with proper tools and have acquired sufficient product knowledge and installation experience. 

There are several other key provisions contained within ANSI A108.19, including grouting, workmanship, movement accommodation, and maintenance, completing a very comprehensive specification for how to install products defined by ANSI A137.3. 

See link here for the full paper, including footnotes. 


Tech Talk – Coverings 2018

Avoiding latex leaching from
tile setting materials

By Colin Cass, Techtile Consulting Pty. Ltd, Australia

This paper was recently presented at the Qualicer ’18 conference in Spain.


The use of polymer/latex type additives that improve the performance of thin-set adhesives and mortars has been in common and increasing use since the 1960s. For decades there have been occasional references to some of these polymer/latex additives leaching from tile work to cause problematic stains on the finished surface. 

As a consultant looking at problems with tile-work over the decades, I have noticed an increase in this specific staining, called “latex leaching” that is sometimes confused with “efflorescence” staining. This staining is far more difficult to treat than efflorescence, but it is easier to avoid. Investigations into this staining have revealed certain changes in products and procedures that are associated with this increase.

This paper does not analyze the chemical aspects of the cause of this staining; rather it explains actions that can be taken by designers, specifiers, builders and tile installers to avoid this problem. 

Changes that make latex leaching more common 

In 1986, a Field Report of the Ceramic Tile Institute of America (86-5-1) titled “Installing Ceramic Veneers with Latex Modified Mortar & Grouts” used the term “Latex Leaching.” In May 1989, Tile & Decorative Surfaces expanded on the issue, opining that “rain is one of the biggest contributors to the leaching

The problem was raised again by the Tile Council of North America (TCNA), which reported the issue in the following way, but just related it to excess water mixed with the grout, not the thin-set adhesive. It stated: 

“What is latex leaching and dirt deposition? Less common than efflorescence is the white residue that can form on polymer-modified grout if the grout is subjected to excessive moisture before the polymers coalesce. Polymer additives are often added to grout to provide superior properties, commonly improved chemical resistance, reduced porosity, improved flexibility, and freeze/thaw stability. These additives are either already in the grout as re-dispersible powders or are added in liquid form. In both cases, grout mixed with too much water or cleaned too soon, or cleaned with excess water, can cause the polymer to migrate to the surface. In many cases (but not all), these polymers are white in color. When the excess water evaporates, the white polymer is exposed.”

While some minor whitish deposits are likely to come from excess water in the grout mix, the serious disfigurement that keeps returning and which is identifiable by having a clear, sticky component that has a characteristic acrylic odor, is from water under the tile, that carries uncured additive to the grout joints. See photos 1, 2 and 3. 

While the problem of latex leaching has been known about for decades, its increasing incidence can be attributed to several changes that have crept into the tile and construction industries over the decades. These changes are:

  1. Larger, denser tiles
  2. Increased use of latex/polymer additives
  3. Thicker adhesive layers 
  4. Increased use of screed isolation layers (membranes and uncoupling mats)

Larger, denser tiles

There has been a world-wide uptake of large-format tiles. 35” x 35” and 48” x 24” porcelain tiles are now commonplace, and the use of “thin tiles” such as Laminam and Kerlite are increasing. These tiles generally have less than 0.5% water absorption, and so water in the adhesive is not taken into the tile back as occurs with twice-fired tiles.

These large tiles are usually laid with narrow joints, usually between 1/16” to 1/8.” This means that moisture in the adhesive is very slow to move to the evaporation point at the joints. This results in slower drying times and slower curing times for the adhesive. 

Increased use of latex/polymer additives

More latex and polymer additives are being used because they are necessary for adequate bond strengths to be attained when dense tiles are used. On top of this, the range of adhesive additives has been changing to include water entrainers and retarders, which can slow the cure of the adhesive. 

Thicker adhesive layers

While “thin tiles” (aka gauged thin porcelain tiles or slabs) are installed using smaller notched trowels, it is general for tiles greater than about 24” x 12” to be laid using 1/2” notched trowels, with adhesive manufacturers usually calling for a minimum 1/8” depth of adhesive and 100% contact coverage. Most manufacturers of adhesives also call for large tiles to be “back-buttered” with adhesive, and this adds to the depth of adhesive coverage.

Some contribution to thicker adhesive layers also comes from unskilled tile installations and other construction trades’ workforce. If surfaces are not true and straight, then extra adhesive is required to pack the finished work out to its proper alignment. Preparation trades who fail to provide good surfaces – or tilers who have poor mortar screeding skills – end up using thicker adhesive layers.

Increased use of screed isolation layers/ membranes and uncoupling mats

For a number of reasons, including efforts to prevent efflorescence staining, there has been an increase in the application of waterproofing membranes over the top of mortar screeds. Often the aim is to prevent water entering the mortar screed and leaching calcium stains out. Such a waterproof membrane prevents moisture in the tile adhesive from being absorbed into the screed, thereby delaying curing and drying of the adhesive. 

The increased use of other dense layers over the screed, such as uncoupling, or crack-isolation membranes made of bitumen or plastics such as polyethylene, have a similar effect of preventing the absorption of water in the tile adhesive into the screed. 

Delayed curing and drying of latex/polymer modified adhesives

All of the above changes result in slower curing and drying of the tile adhesive. For internal tiling, this is not a great issue. It means wall installations need to have supports left in place longer to reduce creep, until a proper cure has occurred, and floors should not be trafficked for a number of days, instead of the usual 24 hours. But when it comes to external tiling, this slow curing and drying can be a major problem.

This delay in curing is specifically referred to in the TCNA Handbook, which at least since 2011 has stated under the heading Latex/polymer modified Portland Cement Mortar: 

“When installing 8” x 8” or larger impervious tiles over a waterproof or crack isolation membrane, or other impervious substrate, longer curing times will be required. A rapid setting latex/polymer modified cement mortar may need to be specified for faster curing. Because latexes vary considerably, the directions of the latex/polymer mortar manufacturer must be followed explicitly.”

Despite this call for the manufacturer’s directions to be followed explicitly, a review of a large number of adhesive product data sheets revealed no mention of delayed curing when dense tiles and the adhesive were used over impervious substrates.

The most ominous warning also comes from the TCNA Handbook, which states:

“When latex/polymer modified Portland cement mortar is used to install ceramic, glass, and natural stone tiles in an area that may not thoroughly dry out in use (e.g. swimming pools and gang showers, etc.) or where initial drying is inhibited (between tile and impervious substrates), it is recommended that the completed installation be allowed to dry out thoroughly before exposure to water. This drying period can range from 14 to more than 60 days depending upon the temperature and humidity and other climatic conditions.”

The issues caused by this delay in curing and drying emphasize the need to specify and use rapid-setting adhesives for all tiling where a delay in curing is likely to cause problems.

The cause of latex leaching 

The problem of latex leaching is not widespread on external tiling. This proves that the adhesives, mortars and installation systems used are suitable and meet the needs of the industry. However, under certain conditions, some components of the latex/polymer modified adhesive leach out and cause staining.

Investigations at more than a dozen sites with latex leaching in Australia revealed a common cause. All the instances occurred when rain fell on uncovered and ungrouted tiling. In one apartment complex, rainfall charts and construction diaries were used to show that the four tiled decks that were suffering latex leaching were all exposed to rain before they were grouted. The six unaffected decks at the complex were grouted before it rained.

The lifting of tiles during investigations almost a year later revealed water still trapped in the ribs of tile adhesive. These decks have an acrylic waterproofing membrane applied over the screed. Often, the residual water had caused the tile adhesive to discolor. This discoloration was present where water had access to the grooves in the adhesive, but was not present where the adhesive rib was closed off. 

Clearly, grouting the tiling helps prevent latex leaching, since even though the grout would allow some moisture to pass, it appears to prevent rainwater from filling the grooves in the tile adhesive. It appears that this liquid water extracts uncured latex or polymer from the day-old adhesive. The movement of moisture under vapor pressure, particularly when sunlight warms the tile surface, takes it to the surface of the grout joints, where, on evaporation, the residues are deposited.

The same applies for wall tiling applications: grouting soon after installation is important in the prevention of water entry. If the wall has an open top, such as a fence or balustrade, it is important to seal the top, possibly with a capping, to prevent water entry.

So, while water entry into ungrouted tiling may not be the only cause of latex leaching, it is certainly a major contributory factor. 


While latex leaching has occasionally been mentioned in professional tile journals for over 30 years, it’s more plentiful today due to changes that have occurred in tiles, tile installation, and construction. These changes include the combination of larger, denser tiles, increased use of latex/polymer-modified mortars and thin-set adhesive, and greater use of membranes and crack-suppression systems under tiles. Under these conditions, the modified cement products take longer to cure, and in some cases, much longer to cure.

If ungrouted tiling is flooded, there is a far greater likelihood of latex leaching occurring, so external tiling should be grouted as soon as possible, to prevent wholesale entry of water into any voids under the tiles. This means covering the ungrouted work if there is any chance of rain. No instances of latex leaching were encountered when rapid-setting adhesive had been used, but the tiling should still be protected if rapid-setting products are used. 

The information supplied by tile adhesive manufacturers is generally remiss when it comes to warning about likely delays to curing and setting times when dense tiles are installed over impervious substrates, and no information was found warning that latex leaching could occur if ungrouted tiling was flooded. More detailed information needs to be inserted into specification and instructions underlining the importance of protecting unfinished tiling from rain and flooding. If the tiling is inundated the wet vacuuming and adequate drying time must be allowed before grouting to avoid latex leaching.

There also appears to be an opportunity for chemical engineers to test if some adhesive additives are greater contributors to latex leaching than others. This could allow for the development of superior external tiling adhesives that would be less likely to present with latex leaching.

The TCNA North American Pavilion

Experience cutting-edge tile design and installation innovations at work

Tile Council of North America (TCNA) is an international trade association representing North American manufacturers of ceramic tile, installation materials, tools, and related products. This year, over 115 TCNA members are excited to showcase their latest offerings at Coverings in Atlanta. In addition to inventive tile designs, you can discover what’s new in the world of tools and machinery, as well as installation materials, all in the TCNA North American Pavilion.

Booth #7832

The TCNA booth (#7832) is in the center of it all as your information and hospitality hub throughout the week. Complimentary lunch will be served Tuesday, Wednesday, and Thursday (no wristband required) and afternoon happy hour bars will open at 3:30 pm (cash, credit and drink tickets accepted). So stop by, refuel, and network with the leading industry associations co-exhibiting with TCNA: the Ceramic Tile Distributors Association (CTDA), the International Masonry Institute (IMI), the National Tile Contractors Association (NTCA), the Tile Contractors Association of America (TCAA), and the Tile Heritage Foundation (THF). TCNA’s Lab Services team will be on hand as well to discuss the research and testing offered at its state-of-the-art Product Performance Testing Laboratory – North America’s largest tile-and-stone-specific facility for independent testing and research. Discounts on TCNA literature will be available for those of you looking to round out your technical library. 

“Why Tile” quickfire sessions

Catch these info-packed 20-minute mini-sessions (running Tuesday through Thursday) on the inherent benefits tile has to offer: Do You Know What’s in Your Floor Covering?

  • Tile: The Greenest Option
  • Tile vs. Competitive Products 
  • Health, Wellness & Tile 
  • Durability: How Do Other Floor Coverings Measure Up? 
  • The Value of Tile (from a Top Realtor’s Perspective). 

Check the Coverings app or Show Directory for times and locations.

Building green

TCNA and TCNA members are synonymous with leadership in building green with tile. The industry-wide, UL-certified Environmental Product Declarations (EPDs) for tile, tile mortars and tile grouts made in North America provide unprecedented transparency on the environmental impact of a full tile installation, making it easier for green builders, designers and specifiers to make informed decisions that satisfy the requirements in top green building rating systems including LEED, Green Globes, IgCC, ASHRAE 189.1 and ICC 700. Those seeking LEED building certification can also look to Green Squared Certified® products, which contribute toward the LEED Pilot Credit, for “Certified Multi-attribute Products and Materials.” For the latest on tile sustainability, be sure to catch Bill Griese, TCNA’s Director of Standards Development and Sustainability Initiatives, in the panel session “Health, Safety, Environment, Design: Specifying Tile in Today’s Sustainability Landscape” (Wednesday at 8:00 am). 

Installation Demonstration Stage and the Installation Experience

Looking for the newest installation materials, technologies and tools on the market? The North American pavilion is where you’ll find them. Throughout the show, TCNA exhibitors and the National Tile Contractors Association (NTCA) will provide live product demos at the Coverings Installation Demonstration Stage (#7201). Get an up-close look at the latest products in action, and tips from the pros on how to navigate common challenges. While you’re there, enter to win one of the free drawings between demonstrations. New in 2018 – Don’t miss the Installation Experience (#8401) where master installers and technical experts from top industry associations – CTEF, IMI, International Union of Bricklayers (IUBAC), NTCA, TCAA and TCNA – will show shining examples of proper installations for various applications throughout the home (see page 46, for details). CTEF will be onsite with information for contractors and installers looking to advance their careers through the Advanced Certifications for Tile Installers (ACT) and Certified Tile Installer (CTI) programs. 

Installer/Contractor tours, luncheons, and exclusive happy hours 

Guided tours of the Installation Materials District leave from the Contractor and Dealer Lounge (#8201) at 11:00 am on Wednesday and Thursday with roundtable luncheons to follow. Badged contractors and installers can visit the lounge to reserve a spot while they’re still available. Exclusive Happy Hours begin Wednesday and Thursday at 3:00 pm. 

Canine creations featured in Art Tile Village

Explore beautiful and unique offerings from boutique tile makers across the continent in the Art Tile Village – the largest assembly of decorative tile artisans under one roof! Displayed in the courtyard (#7249) you’ll see one-of-a-kind tiled dog houses created by TCNA members. The artful abodes will be donated to an Atlanta-area pet charity, which will be onsite during the show with some furry, four-legged companions. Be sure to stop by – you may just make a new friend!

Whether your main objective at Coverings is to network with colleagues, find design inspiration from the newest trends, or learn about the latest advancements in tile technology, exciting discoveries await you in the TCNA North American Pavilion. 

Business Tip – Coverings 2018

Change or be dragged:
How to reinvent yourself when life demands it

Paul G. Krasnow, author of The Success Code: A Guide for Achieving Your Personal Best in Business and Life (J & K Publishing, 2018, ISBN: 978-0-692-99241-8), approaches the personal and professional changes that life inevitably brings our way as opportunities to reinvent ourselves – and thrive. 

“When you face a setback in your life, you have two choices,” Krasnow said. “Remain stuck or move forward; it’s that simple. Life is too short to spend it stuck and miserable. Take action now to change your life or get ready to watch life pass you by.”

Krasnow’s book tells the story of Krasnow’s journey – from his modest beginnings in 1940s Los Angeles, to starting over again after business failure, to his epic career rise as a financial representative at Northwestern Mutual Life Insurance Company.

Krasnow offers the following tips on embracing change and creative reinvention when life demands: 

• Realize it’s never too late. During the course of your lifetime, you will be called upon to reinvent yourself, time and time again. Don’t let yourself stay stuck in what you know. Make the most of the resilience you now have under your belt with overcoming previous challenges and strive for new horizons. As you envision this new version of yourself, what are some steps you can take today to put that new self into action?

Take an honest look at your life. Muster the courage to look at your life and figure out where you’ve gone wrong, and the changes you need to make to get back on track. Own up to the mistakes you have made and take responsibility for the part you played in getting yourself stuck. Krasnow points out that this kind of brutal honesty is not for the faint of heart. It requires courage to take full responsibility for your life and most importantly for the failures in your wake. But if you can sit down and face your own mistakes, you will free yourself up to learn from the painful consequences you are facing today.

Move forward; just do it. “Change is not rocket science,” said Krasnow. “We all have a tendency to make life so complicated when it doesn’t have to be. Simply make a decision to move forward. Don’t try; just do it. People say they’re going to try to change. Try? There is no such thing. There’s doing it or not doing it. ‘Try’ is a word that you should eliminate from your vocabulary right now.” 

Dream big. The only real challenge in creating the life you’ve always wanted is your inability or unwillingness to free up your imagination to envision your dream in all of its glory. In other words, you are only as successful as your perceived limitations. How often do you limit yourself when envisioning the success you are capable of achieving? Don’t settle for the limited vista of your present-day life. Instead, allow yourself to be willing to travel well beyond the bounds of the landscapes you may not be able to imagine today. 

Stay focused. “Once you decide to make a change in your life, it’s time to get serious and focus on your goals,” said Krasnow. “Think of life as a journey in a train that travels on a track. Each track leads to a specific destination. Make a point of staying on the track of your choice, without getting distracted and switching tracks. If you stay focused, you will certainly reach your desired destination.” 

Pace yourself. Making a major life change requires a steady pace. You work at it each day and keep at it (and then keep at it some more). Remember that extraordinary creations are not built in a day through occasional bursts of effort, but rather are crafted over long periods of time with daily, steady tasks. It’s a marathon; stop exhausting yourself by sprinting from place to place. Instead, stay on course with your goals and remain consistent. 

Know that failure is not an option. “When you realize that failure is not an option, it becomes clear that there is no stopping at the first obstacle you encounter along the way,” Krasnow said. “There is an opening, even in the most stubborn of barricades. Where is the opening in your current wall of obstacles? Is there a secret passage you had overlooked but is now emerging in front of you? Take that hidden path and forge ahead. Just keep your eye on where you want to go and you might find that a setback along the way was actually a shortcut to your desired destination!”

“We all know that change is not the most comfortable part of our lives,” concluded Krasnow. “But know that the process of transformation is a gratifying experience, providing you find the courage to do it. You can adapt. You can take a new path in your life. And you will undoubtedly be better for it in the long run.”

For more information, please visit

Ask the Experts – Coverings 2018

Ask the Experts Q&As are culled from member inquiries to NTCA’s Technical Support staff. To become a member and make use of personal, targeted answers from Technical Support staff to your installation questions, contact Jim Olson at [email protected]


I will begin by letting you know that I have 25 years in the industry with tons of training and on-the-job experience. 

I have multiple showers having crazing. The crazing is starting to happen a few weeks after installation and it is all over. All are installed with cement backer board, roll-on waterproofing with premium thinset and grout. No structural issues are evident.

I’m using good quality ceramic tile imported from three factories. I have sold a couple of million square feet of tile and I have gotten maybe one case of crazing a year, but now I am seeing it very often. Are you hearing this also? Are there any new recommended installation procedures? 

Even though I am importing a container at a time of each color with the same lot, 99.99% turn out fine, and then crazing appears on isolated jobs. Looking forward to some input.


It sounds like you purchase and install a significant quantity of these tiles. Have you contacted the tile manufacturers? Have you compared lot and run numbers from cartons of tile used in the failed installations? Perhaps the manufacturer(s) have had some issues with application of some glazes to certain tile bodies in certain lots or runs that could correlate to the failures you are experiencing.

Have the tiles been manufactured to ANSI A137.1 specifications?

Do you know whether the tiles have been tested to meet or exceed ASTM C424 for Crazing Resistance? This is a destructive test performed on tiles that meet ANSI A137.1 Specifications for Ceramic Tile. In this test, tiles are subjected to 150 psi steam pressure. Tile samples that pass the test show no evidence of crazing. Refer to ANSI A137.1, subsection

Do you know whether the tiles have been tested to meet or exceed ASTM C484 for Thermal Shock? (ANSI A137.1, subsection

As far as recommended installation procedures, it sounds like you are employing a version of TCNA Handbook methods B415 or B421 or B422 with a cement backer board and a liquid, surface-applied waterproofing membrane. Do you suspect any of the concerns listed below may exist in the installations that are exhibiting crazing?

  • Proper / improper installation and cure time of the liquid waterproofing membrane
  • Excessive bond coat thickness
  • Proper / improper cure time prior to grouting
  • Change in plane movement joint installation

You mentioned you are not able to determine the quality of the framing or whether there is deflection in the substrate. Are you able to learn from the building’s owners or building records whether there is wood or metal framing and whether the framing on the failing installations was properly braced to support a tile installation?

Was the board properly gapped between sheets at horizontal and vertical joints, filled with Portland cement mortar and taped with alkali-resistant mesh tape? Were open joints left between the boards where they meet at inside corners to allow for movement at the change in plane?

As you can see, I have more questions for you than answers at this point. Some, or a combination of the items described above may have an effect on the system performance. I suggest starting with the tile manufacturer and determining whether the tiles have been tested to ANSI A137.1 specifications and if there may be a correlation or concern with the lots that are failing.

Natural Stone Institute Announces New Staff Member

Oberlin, OH, March 26, 2018— The Natural Stone Institute is pleased to announce that Dacia Woodworth has joined the staff as Architect & Design Community Liaison and Special Projects Manager. Initially she will focus on expanding industry awareness of the association’s natural stone testing lab capabilities. Her primary role will be expanding outreach to architects and designers to promote the use of natural stone.

Dacia Woodworth, Natural Stone Institute

Dacia is a past board member who has served as an active volunteer with many Natural Stone Institute programs, including Women in Stone and the CEU program. She has worked in the natural stone industry since 2001 in a variety of roles including project management, sales and marketing, education, and technical assistance.

Natural Stone Institute CEO Jim Hieb commented: “Dacia’s industry experience will be a tremendous addition to our team as we expand our outreach to architects and designers. Her firsthand knowledge of the natural stone industry makes her uniquely prepared to educate industry members about the testing lab and other association programs.” Dacia remarked: “I am thrilled to be joining such a dynamic team and to be doing a job for which I am truly passionate.”


About the Natural Stone Institute

The Natural Stone Institute is a trade association representing every aspect of the natural stone industry. The current membership exceeds 2,000 members in over 50 nations. The association offers a wide array of technical and training resources, professional development opportunities, regulatory advocacy, and networking events. Two prominent publications—the Dimension Stone Design Manual and Building Stone Magazine—raise awareness within the natural stone industry and in the design community for best practices and uses of natural stone. Learn more at


New Natural Stone Institute Technical Bulletin

A new technical document covering the testing of dynamic coefficient of friction (DCOF) of natural stone is now available in the Natural Stone Resource Library.

Since the withdrawal of the ASTM C1028 test method for Static Coefficient of Friction, the stone industry has been without a standard test protocol for the measurement of friction for walking surfaces. The Natural Stone Institute has completed an exhaustive study on the use of the ANSI A326.3 Standard Test Method for Measuring Dynamic Coefficient of Friction of Hard Surface Flooring Materials test procedure on natural stones. Over 300 stone specimens (51 stone types in six different finishes) were tested to evaluate the appropriateness this test method for natural stone products.

The Natural Stone Institute would like to thank Miller Druck Specialty Contracting, Artistic Tile, Coldspring, Tennessee Marble Company, and TexaStone Quarries for their assistance in procurement of test specimens.

To access the document, please visit


About the Natural Stone Institute

The Natural Stone Institute is a trade association representing every aspect of the natural stone industry. The current membership exceeds 2,000 members in over 50 nations. The association offers a wide array of technical and training resources, professional development opportunities, regulatory advocacy, and networking events. Two prominent publications—the Dimension Stone Design Manual and Building Stone Magazine—raise awareness within the natural stone industry and in the design community for best practices and uses of natural stone. Learn more at


OSHA Considering Changes to Silica Rule

OSHA may soon make it easier for employers to comply with the agency’s Respirable Crystalline Silica in Construction Standard. The standard, which OSHA announced in 2016 and began to fully enforce last fall, seeks to protect workers who may inhale silica dust.  A variety of construction operations may expose workers to silica dust including, for example, abrasive sandblasting and cutting bricks, stone, or concrete.

The silica standard is extremely detailed and complex. It contains requirements for assessing workers’ silica exposure, for using exposure control methods and respiratory protection, for offering medical surveillance, and for keeping silica-related records.  Fortunately, “Table 1” of the standard makes compliance with standard easier, at least in some situations.  The Table describes engineering controls, work practices, and respiratory protection requirements that may be implemented by an employer when performing certain construction-related tasks, thereby exempting the tasks from the standard’s exposure assessment provisions and permissible exposure limits.

Last week, during the mid-winter meeting of the American Bar Association’s Occupational Safety and Health Law Committee, a Department of Labor official announced that OSHA is considering changes to the silica standard for construction. According to Ann Rosenthal, the Department’s Associate Solicitor for Occupational Safety and Health, OSHA is currently working with members of the construction community to add more tasks to Table 1.

News that OSHA is considering an expansion of Table 1 comes after a recent federal court ruling that rejected several challenges to the standard by employer groups. The U.S. Court of the Appeals for the District of Columbia Circuit, in an order issued last December, rejected arguments from employer groups challenging the standard’s lower permissible exposure limit and, among other things, the feasibility of compliance with standard

Written by authors Alyssa Levy, Patrick Miller, Matthew Morrison, and Dana Svendsen at Sherman & Howard, L.L.C.

Crossville, Inc. releases update to its Installation Manual for gauged porcelain tile panels.

Crossville, Tenn. – Crossville, Inc. has released an update to its Installation Manual for gauged porcelain tile panels. The revised technical manual, offered in English and Spanish versions, highlights Crossville’s compliance with ANSI A137.3 standards and reinforces proper interior installation per the ANSI A108.19 standard.

In 2017, Crossville led training for more than 400 professionals in the installation of gauged porcelain tile panels. Cumulatively, the company has trained 1,500 porcelain tile panel installers through sessions on site at Crossville headquarters and at workshops co-hosted with industry partners and associations.

Crossville‘s Derrick Patterson of the technical services team was instrumental in the revision of the Installation Manual, ensuring it conveyed Crossville’s compliance with ANSI A137.3 and supported the ANSI A108.19 installation standard, as well. Notably, technical services director Noah Chitty was among the industry experts at large who collaborated to develop the installation standard for this burgeoning product category.

“It’s our goal to support installers with the education and practical know-how they need, and our technical guide is just one of many ways we’re here to help,” Chitty explains. “Their work is the cornerstone of the growing success of the gauged porcelain tile panel category.”

Both the English and Spanish versions of the manual are available at

Qualified Labor – March 2018 – Kris Nardone

NTCA starts Kris Nardone on the path towards certification

In the summer of ’17, Kris Nardone, owner of K_Nardone Custom Tile Work, Kennesaw, Ga., became Certified Tile Installer #1364, at a Certified Tile Installer (CTI) exam at The Tile Shop in
his town.

After 20 years as a tile setter – and now with over six thousand followers on Instagram @k_nardonecustomtilework – Nardone said he took the exam because “Being a certified tile installer adds credibility to myself and my business.”

But it all started when he joined NTCA in 2016.

“The NTCA gave me a network of people and information that I didn’t have before,” Nardone said. “I spoke to another Certified Tile Installer about the CTI exam. I had attended a NTCA workshop in 2017 and met a local CTI exam instructor who also spoke to me about the CTI exam.

“After finding out more about the test, I knew that this certification would represent my experience in the trade and allow me to network within the industry,” he added. “I’ve always used industry standards. If I can be a part of a network of people that help add knowledge to my business and continuously improve my trade then I’m all for it.”

Nardone spent time preparing for the exam. “I read the CTEF workbook a couple times and looked at social media to make notes,” he said. “I also brought a list of key components to the test that I thought were important to track my day/progress. Every minute of the hands-on test counts. Layout is key! Other than that, I set tile daily. If you can think of it, I can tile it.”

His job experience made the book section of the exam relatively easy, but the hands-on portion was another story. “I thought the hands-on portion would be a breeze in the beginning, and then I heard from other certified installers not to underestimate the exam,” he said. “After taking the test, I know now that it does challenge your skills and knowledge as well as your time management. There are over 200 cuts in nine hours and it will test you mentally and physically.”

The time management aspect of the job varied significantly from the typical time management employed on a job. For instance, Nardone said, that on a typical job, he estimates “the time to complete the job and [I] push myself to complete the job in a timely manner, but I am always trying to do the best job possible for the homeowner no matter what it takes.

“The test is a set amount of time to get it right and get it completed,” he added. “It mentally tests you. Stay focused. Believe in yourself and get the job done.”

Being in an atmosphere of earnest demonstration of a tile setter’s skills was inspiring to Nardone. “You are working around others taking the test,” he said. “It was great to see that others take as much pride in their work as I do. Like any job site, if you can work well with others, you’ll get the job completed faster.”

Nardone, who plans to also pursue Advanced Certification for Tile Installers (ACT), recommends taking the exam to expand setters’ businesses and further their personal development and knowledge. “Though taking the test, you’ll make new contacts, friends, and learn more about the industry,” he said. “Those who don’t consider the exam should look more into the benefits of taking the test. It’s there to help you, your career, and the consumer.”

Nardone emphasizes that the CTI credential “assures the customer that they are receiving a quality install the first time… I have spoken to customers that have used other companies to meet their deadline or their budget and less than a year later – sometimes a month later or upon completion of install – the tile installation starts failing with cracking grout, unbonded tile, shower pan leakage, excessive lippage, etc. Hiring a Certified Tile Installer assures the homeowner that the installer is up to date on industry standards and is qualified to set the materials needed.”

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