Scribing: demonstrating artistry and craftsmanship in creative tiling

Those familiar with tile recognize that stunning tile installations have stood the test of time and endured as practical works of art for generations and generations.

Today’s tile setters participate in that tradition of precision and artistry with every job. And there are some techniques that take tile craftsmanship to the next level. Scribing is one such technique.

“Scribing is an art form,” said NTCA member Joshua Nordstrom, of Tierra Tile in Homer, Alaska. “It highlights the level of skill, detail, and abilities that you’re capable of.”

Scribing “gives an install a more artistic feel – it’s more personal – which is great for our industry because as tile setters, we are artists, and it’s nice to be able to do something creative to showcase that fact,” agreed Jason McDaniel, NTCA member of Stoneman Construction, LLC, in Tualatin, Ore.

Scribing is done “when a factory tile meets an organic shape such as pebbles, natural stone, or around an irregular shape,” Nordstrom explained. “Pebble scribing is very common because cutting pebbles in a straight line doesn’t look or feel like a natural transition,” McDaniel added. “Over the past few years, it has become more common to see a pebble scribe.

“Personally, because I like to scribe, I decided to do a mosaic hex scribe and see how that would look,” McDaniel said. “It looked amazing and now we scribe everything.”

“Personally, because I like to scribe, I decided to do a mosaic hex scribe and see how that would look,” McDaniel continued. “It looked amazing and now we scribe everything.” 

While there are many ways to customize a project, scribing can make the job truly original. Nordstrom says in his Alaskan community, his clients like to incorporate nature endemic to the area into their tile designs, often in bathrooms and entryways. “I offer my clients a personal touch for their tile install, from an elaborate mural to a simple medallion, he said. “I find that I can sell a scribed mosaic in about six out of 10 jobs. Most people like to add just that little touch to set their home apart from the rest.”

Scribing takes a combination of skills, all of which begin with PATIENCE. “Scribing is a game of patience that requires time and experience to master,” Nordstrom pointed out. “It takes as long as it takes,” said Kyle Gaudet of Flawless Floorz, a NTCA member in Brentwood, N.H., “Take your time – even extra time – until you’re comfortable with what you’re doing.”


The essential skill of templating

Nordstrom's Kraken drawing and cut out

Nordstrom’s Kraken traced life size on a Tyvek ‘canvas.’

An essential skill to clean scribing is templating. “I template everything when it comes to scribing a mosaic,” Nordstrom said. “It all starts with a scaled drawing that gets blown up with a overhead projector and traced life size on a Tyvek ‘canvas.’ Once it’s all colored and labeled, I go over it with tracing paper creating each individual template. Once everything is cut and installed on a fiberglass mesh, I lay the mosaic over the field tile, trace it out and scribe it in.”

McDaniel’s first step is templating as well. “I precut all of my tiles for the floor or wall and then I overlay the pebbles or mosaic that I am going to scribe,” he explained. “I trace the outside of the tile with a sharpie and then use a grinder and remove the sharpie mark. Once the scribe is completed I take a diamond pad or sanding disc to ease over the cuts and make them look smooth and finished, taking all of the chips out of the scribed area. I have found that precutting the area and overlaying is by far the easiest method to use when scribing.”

“Pebble scribing is very common because cutting pebbles in a straight line doesn’t look or feel like a natural transition,” McDaniel said.

McDaniel’s pebble scribing

McDaniel didn’t always use this method. “The first scribe I ever did was a pebble scribe,” he said. “I made templates using wax paper, which was grueling and time consuming, and not as accurate as overlaying and tracing. Overlaying and tracing allows you to set the field tile first, letting that area dry. Coming back in the next day and setting your scribe mosaic allows you to make the transition between field tile and mosaic tile perfectly flush, as it should be.”

Gaudet uses a “traditional” 2” piece of the tile for a scribing piece, marking every piece contour by contour. “I also use a 5” and 4” angle grinder, nippers and dry polishing pads,” he said.


Scribing tools; dealing with varying thicknesses

In terms of tools, McDaniel scribes everything with a grinder with a 6” turbo mesh blade, which gives him the best accuracy given the amount of plunge cutting necessary in scribing. “The larger blade allows you to go deeper into the tile before you hit your grinder. Saw horses and clamps are a must have to hold the pieces in place. After I finish my scribe, I ease all of my edges with a 100 grit sanding disc, or a Dremel tool for tighter corners. I am aware that Joshua Nordstrom does all of his scribing with a tile saw and I find that to be absolutely amazing!”

Nordstrom's Kraken drawing and tile

After everything is cut and installed on a fiberglass mesh, Nordstrom lays the mosaic over the field tile, traces it out and scribes it in.

In fact, Nordstrom uses a 10” wet saw, resorting to a grinder only if it’s necessary to remove some material from the tile back to achieve the same thickness between different tiles. “I have learned over the years that installing a fiberglass mesh on the backs of my mosaics really simplifies the installation,” he said.

McDaniel said scribes can be mounted on membranes or thin backer board, though he prefers to “screed my scribed area with thinset so that I can adjust each piece meticulously, insuring that I have a consistent grout line that matches the rest of my install. It also depends on what you are scribing. Sometimes glass mosaics can be difficult to deal with, so pre-mounting them is a worthwhile step.”

Considering thickness is key when scribing, and matching the tiles or grinding the tile backs is sometimes necessary to achieve the proper thickness. “Sometimes when installing you may need to use different trowel sizes to accommodate the height difference in the tile,” Nordstrom said.

McDaniel said his greatest scribing challenge was installing pebble mosaics around a large piece of walnut in an entryway.

McDaniel said his greatest scribing challenge was installing pebble mosaics around a large piece of walnut in an entryway.

McDaniel tells about his most challenging scribing task – installing pebble mosaics around a large piece of walnut in an entryway. Engineering expansion and elevations among the four surfaces and four thicknesses was tricky, he said. “With anything tile, planning ahead and having a game plan going in is essential to being successful,” he said. “Having a start and stop point, keeping your area clean, making sure you have expansion, using anti-fracture membranes, uncoupling membranes, better setting materials, non-sag thinsets; all of these things make your job easier.”

Pricing the job is personal. Nordstrom figures out how many hours it will take him to cut and install, price it on an hourly or date rate, and figure in a little extra for margin of error. Gaudet, whose company is new to scribing, said his client was initially resistant to scribing and the associated upcharge. But “after showing him a few of the pieces, he was in total agreement with my opinion to scribe that wall,” and to agree to pay the upcharge due to the look.

McDaniel, though, doesn’t charge extra for scribing. “I have never made money on a scribe,” he said. “I do it because I want my work to stand out. I want to be known as an artist and a craftsman. Maybe someday I will make money from my scribing ability, but for now I am okay with being considered a ‘Tile Badass’.”

In addition to taking your time, starting small and having patience, McDaniel said the most important thing when scribing is to have confidence. “Know that you can do it; know that you are doing something different that is going to stand out when seen.” He also recommended following the work of several tile setters who have been successful with scribing – and reaching out to them for advice: Robert Davis, Mike Soho, Zack Bonfilio, Tom Habelt, Carl Leonard, and Hawthorne Tile. In addition, he recommended viewing the videos and pictures posted in several tile-centric Facebook groups: Global Tile Posse, Tile Geeks, Tile Love 2.0, The Misfit Tilers, and Tilers Talk to get more information and inspiration.

If you are looking to give it a try, here is the first video in a series Nordstrom created on scribing. The remaining videos are available on the NTCA YouTube channel.

Should I grout the old fashioned way with mud cement?


I am looking for an opinion. I have installed a 4˝x8˝ porcelain outdoors with thinset with 1/4˝ joint. I wanted to grout the old fashioned way with our mud cement – with extra Portland – cleaned with sawdust. I feel that the joints were full years ago. Thank you so much, I look forward to your opinion.


While the system of grout you described may work well, depending on your ratio of materials, many of the modern grouts available today have been engineered to stand up to harsh climates and use.

Reading and following manufacturers’ instructions carefully, along with a little practice, will produce full joints and great results with today’s materials. I suggest checking with the setting material company that makes the thinset you’ll be using for their suggestions of grout for your installation.

Regardless which grout system you use, an exterior installation has many critical elements that must be addressed. Please refer to the Tile Council of North America Handbook For Ceramic, Glass and Stone Tile Installation for the appropriate method, details and materials for this installation. 

OSHA silica standards for construction

Revising Table 1 – now is the time to act

By Tile Council of North America staff

The Occupational Safety and Health Administration (OSHA) has announced plans to reopen the Occupational Exposure to Respirable Crystalline Silica ruling, primarily focused on possible changes to Table 1 of the silica standard. Table 1 is a listing of construction tasks with engineering controls, work practices, and possible respiratory protection that provides compliance certainty for those tasks. Currently it’s comprised of only 18 common construction operations, each with their own limitations. The list can be found at or 

The notice to reopen the rule is currently at the Office of Management and Budget (OMB) for review before publication in the Federal Register. A 60- to 90-day comment period is expected once the notice is published. To take advantage of this unique opportunity, companies wanting changes to Table 1 must organize quickly and assemble data to support their requests.

Table 1

If a task is listed on Table 1, and the employer ensures that all requirements are followed, the employer does not have to conduct an exposure assessment for that operation. However, the list is far from exhaustive and includes limitations. For example:

  • Several tasks, including cutting fiber-cement backer boards, are limited to only being conducted outdoors. This excludes not only performing the task indoors, but also in “enclosed areas,” which would include garages and many other partially enclosed locations.
  • Many tasks include only one type of engineering control, often water-based. In some instances, vacuum-based controls are currently available but have not been included in Table 1.
  • Some tasks limit the size of the blades that can be used.

In addition, there are some common activities that are not included in Table 1, such as:

  • Mixing mortar, self-leveling underlayment (SLU), and other silica-containing materials using a variety of powered equipment.
  • Shot blasting for floor preparation.
Excerpt from Table 1 showing exposure control methods required for stationary masonry saws.

Excerpt from Table 1 showing exposure control methods required for stationary masonry saws.

Opportunity for changes to table 1

After the initial announcement to reopen the Occupational Exposure to Respirable Crystalline Silica ruling in late 2018, Tile Council of North America (TCNA) staff met with OSHA to discuss the details of this upcoming action. TCNA’s understanding is that OSHA will be looking for at least two types of changes to Table 1:

  • New additions. Submittals can include proposed categories, engineering controls, and PPE requirements (for example, if supported by data, mortar mixing with a 300-rpm drill equipped with a mixing blade, adding water before powder, and without PPE if under four hours per day).
  • Enhanced equipment requirements. Industry can propose new engineering control requirements for tasks already on Table 1, which could change the PPE requirements. For example:
    • With air filtration or water flow rates set above the current thresholds, perhaps PPE requirements could be less restrictive.
    • Some tasks are currently limited to outdoor use only. With data from indoor operations, it may be possible to show that operations conducted indoors, or in enclosed areas, are also below the action level of the rule for certain tasks.
Scoring and snapping is not currently listed in Table 1

Scoring and snapping is not currently listed in Table 1, however in their FAQs, OSHA lists the use of score and snap cutters (or tile splitters, as they refer to them) as one of the activities not expected to expose workers to silica levels of concern.

Beyond adding tasks to Table 1, companies can also use this opportunity to clarify issues they identified through efforts to implement the rule. For example, some companies have raised the question of how to differentiate between a grinder and a saw, especially when the same piece of equipment can be used in both capacities. Grinders and saws are currently treated differently on Table 1. While presumably the difference lies in whether a saw blade or grinding wheel is attached, with Table 1 being revised, that can be clarified by OSHA with no ambiguity for the OSHA inspector and installation company.

Mixing mortar is not one of the 18 construction tasks listed on Table 1.

Mixing mortar is not one of the 18 construction tasks listed on Table 1. Companies that desire changes to Table 1 should prepare now by formulating their request and evaluating their data.

Immediate benefits

The process to potentially change Table 1 will be lengthy, with revised standards likely not out for at least a year. However, data provided to OSHA for changes to Table 1 may be immediately useful as “credible data” when assessing exposure to employees, which is required by the standard for all tasks not following Table 1 requirements.

Prepare now

The window to revise Table 1 is relatively narrow. Given OSHA’s schedule, we expect the notice requesting data to be published this summer, with the 60- to 90-day comment period extending into early fall. Companies that desire changes to Table 1 should prepare now by formulating their request and evaluating their data. If additional data is needed to fully characterize exposure, the effect of controls, or required PPE, companies need to identify that right away to collect the required information.

More Information

For more information on the OSHA silica standard, a convenient list of frequently asked questions is available at: or 

Important note 

This article is to help raise awareness of what TCNA staff believe are important issues for the reader. Please understand, however, that these issues often involve complex regulatory issues that are not easily summarized and that may vary in application based on specific facts and circumstances. Therefore, this article is offered as is, for informational purposes only, and readers should not rely on it for legal or other professional advice. Readers should conduct their own review and seek appropriate professional advice for their specific

Should this be a demo or can I replace the shower pan?


I have a customer that has a shower stall they would like updated…a little. New custom glass enclosure, new fixtures, and…a new pan? The two walls of the shower are white quartzite. She is in love with it and does NOT want to remove it. However, the pan is fiberglass. She does not like it and it has stains that won’t go away. She would like to have some kind of stone or tile to replace the pan.

My questions: 

  1. Will I be able to make a pan that won’t fail in years to come?  
  2. I would expect that the fiberglass pan has a flange that wraps up behind the slabs of quartzite. If so, how do I address that


Thanks for getting in touch with us about this problem. Let me address your questions first:

1. Many shower pans have been made from tile and related components that, when properly constructed, last for a very long time. There are many methods to construct such a pan. Have you built a shower pan before? Which method or system do you use or are you familiar with?

2. You are correct that the existing pan likely has a lip that extends behind the first course of tile and possibly behind the substrate. As your question suggests, it would likely not be an easy or simple task to remove the band of the quartzite, patch or install the waterproofing membrane that may or may not be behind it, and replace the membrane and the quartzite and the pan with a new tile system that you will be comfortable with installing and selling to the owner as a functional system that will stand the test of time.

I suggest you determine the best method and system approach that you are comfortable with, and then discuss with the owner the reasons why it makes much more sense to demo, replace and upgrade the entire shower.

I look forward to hearing back from you so I can help guide you on the best way to continue. 

Important updates to LEED® EPD provisions and relevance to tile

In February 2019, the U.S. Green Building Council (USGBC) released the newest edition of Leadership in Energy and Environmental Design (LEED), Version 4.1. From review of the updated criteria, a prioritized focus on reduced carbon pollution can quickly be observed. This has resulted in objectives that are more achievable than before, which emanate from expanded product life cycle considerations and that are generally favorable for tile. 

Updates to the Credit, Building Disclosure and Optimization – Environmental Product Declarations (EPDs), are substantive. Similar to v4.0, the use of products with EPDs can earn up to two points on a LEED v4.1 project. One point can be earned if enough products transparently report life cycle environmental impacts. A second point can be attained if enough products are selected on the basis of optimized life cycle environmental impact reduction. Where v4.1 differs is in its expanded recognition of industry-average environmental impact reporting and its focus on carbon footprint comparison.

Benefits for tile in v4.1

For tile, the LEED v4.1 EPD updates mean the following: any tile, mortar or grout represented by one of the several tile industry-wide EPDs can contribute one full product toward a 20-product threshold required to obtain a point on a LEED v4.1 project. That’s compared to the former 0.5 product contribution in LEED v4. This means that specifying a single tile system – tile, mortar, and grout – which is represented by an industry-wide EPD, could satisfy three of the 20 products required for an entire building.

Furthermore, opportunities to obtain a second EPD point through the use of tile on a LEED v4.1 project are more attainable than they were with v4. Previously for v4, 50% by cost of all products used on a project had to have an environmental footprint lower than the industry average across three different environmental impact categories. With v4.1, only a minimum of 10 “optimized” products is required. What’s more is that a building material counts as 0.5 product if the manufacturer simply has a life cycle impact reduction plan for that product, regardless of whether it’s better or worse than industry average. Additionally, a building material can contribute one full product if its carbon footprint is lower than comparable building material(s) considered for the same function, 1.5 products if it has a 10% lower carbon footprint, and two products if it has a 20% lower carbon footprint. 

Industry-wide EPDs facilitate optimization strategies 

For tile and EPDs, the big picture LEED v4.1 takeaway is simple. Industry-wide EPDs are helpful now, more so than ever before. USGBC has clearly emphasized the importance of industry-averaged life cycle data, which is inherent to EPDs, as such data is critical toward optimized environmental life cycle performance. Not only do products included in industry averages now contribute a full product toward the environmental life cycle transparency threshold, such data can be used as an important reference point for a manufacturer to strive for optimization through continuous improvement. Averaged data can also be used to compare carbon footprints of two separate types of products within the same product category for optimized specification. Industry-wide EPDs facilitate both optimization strategies. 

With industry-wide EPDs and the direction in which USGBC continues to evolve with LEED, the tile industry remains poised for “sustained” contribution to LEED building projects for years to come. 

TileLetter Green issue discusses eco-centric issues in the tile industry

Welcome to the Green Issue of TileLetter! Each year, we take a look at some eco-centric issues that impact the tile industry in our August issue. In this issue, TCNA staff examines the revision process of OSHA’s Table 1, as it relates to the Respirable Silica Rule. We also feature a Letter to the Editor from James Woelfel that takes a different perspective on the feasibility of OSHA regulations in protecting worker health. 

Terri Hogan Dreyer, managing partner/principal, NANO Architecture|Interiors, discusses how natural materials like tile and stone are foundations for her firm’s quality control process. TCNA’s Bill Griese tours us through the latest version of LEED – LEED v 4.1 – that generates more achievable objectives that build on expanded product life cycle considerations and are favorable for tile. 

Our Training and Education feature explores the recently DOL-approved NTCA National Apprenticeship Guidelines for members, which provides a career road map in the tile trade, explaining the process of developing this program and how this will benefit members and the entire trade. NTCA’s Becky Serbin takes it a step further in the NTCA University Update, describing how the establishment of the apprenticeship program will mandate more course development to support the finisher and setter tracks. 

We meet Jake Swoboda in our Member Spotlight, one of the younger members of the industry, and learn how he is carving a path to tile setting success, based on familial training from his uncle, and augmented by his CTI credentials and membership in NTCA. 

In this issue, we also bid a sad farewell to a beloved member of the tile industry and all-around nice guy, Steve Rausch. Though he will be deeply missed, all of us who knew and worked with him are richer for having known him. His sudden passing reminds me to let people who are important to me know I appreciate them – personally or professionally. Maybe there’s an opportunity for you to do the same in the coming month. 

God bless,

If a shower floor slope is 1/4″ per foot are other horizontal surfaces also 1/4” per foot?


I have a quick question about how much slope a shower bench or shower dry-off area should have.

The TCNA Handbook states that “All horizontal surfaces, for example shower seats, sills, curbs, etc., must slope towards drain.”

Shower floor slope is 1/4″ per foot. Are the other horizontal surfaces (bench, etc.) also supposed to be 1/4” per foot?


Yes, the correct slope for all horizontal surfaces is 1/4″ vertical (minimum) up to 1/2″ (maximum) for every 12” of horizontal run. 

– Mark Heinlein,
NTCA Training Director

Uncoupling membranes methods and standards: a timeline

In 1987, a new product category was launched in the North American Tile industry called “Uncoupling Membrane.” The product – an orange membrane – was made of polyethylene, ribbed in one direction and had a polypropylene mesh heat-bonded on the underside. This product was only 3/16” (4.5 mm) thick and 3’ 3” (1 m) wide and only weighed 45 lbs. (20.4kg) for a 323 sq. ft. (30 sq.m.) roll.


Surprisingly, one of the most popular uses of this very flexible and non-rigid membrane was over plywood substrates, including over a single layer of plywood. In 1999, the first detail for a “Proprietary Membrane” with double layer of wood subfloor on 24” (600 mm) on-center (o.c.) joist spacing was introduced to the TCNA Handbook (F147). Then, only two years later in 2001, a second detail was added to the Handbook for going over a single-layer plywood floor on 19.2” (480 mm) o.c. joists with an “uncoupling system.” There was no reference to the manufacturer under limitations. The term “uncoupling” was substituted for “proprietary membrane,” and a definition was added to the prologue:


“Uncoupling Systems: A system that separates the finished surface from the substrate to allow the independent movement between the two and prevent the transfer of stresses to the tiled surfaces.” 

For those of you who attended that meeting in Clemson, S.C., you will remember that this was the year that the TCNA Handbook Committee voted to approve removal of anything in the Handbook that had proprietary names, which included the section for “Floors Sound Rated.” Then around 2006-2007, a directive was issued to describe a “DITRA”-like product. This definition resulted: 

“Uncoupling membrane: A plastic membrane system geometrically configured to provide air space between the tile and the substrate to allow independent movement between the two and limit the transfer of the stresses.” 


The last detail added to the TCNA Handbook for uncoupling was in 2007 for “Young Concrete” Detail F128. The concern with young/green concrete is that the concrete slab has large amounts of residual moisture that still need to be released from the concrete. This release of moisture can affect the curing of the mortar and the grout. Many crack-isolation/waterproofing membranes – specifically those membranes that are flat – have limited resistance to pressure from moisture since there is nowhere for the moisture to be released. This in turn creates pressure that can cause the membrane to bubble or debond from the concrete slab. The TCNA Handbook declares that an uncoupling membrane must have free space or empty cavities on the underside of the membrane that inherently allow for moisture/vapor release and eventually equalization. 

The TCNA Handbook prologue uncoupling definition was updated again in 2014 to include: 

“The uncoupling membrane must achieve 50 PSI or greater shear bond strength in 7 days per the test method in ANSI A118.12 Section 5.1.3.”

This addition was in response to the concerns conveyed by labor and some forensic consultants that there were certain so-called “uncoupling membranes” that were failing to the extent of several millions of dollars for repair and damages. The main mode of failure was traced to the bond between the substrate (majority plywood) and the underside of the membrane where the fleece/mesh or other had delaminated. Until an ANSI standard is created for uncoupling, this requirement is a reasonable stop-gap to identify those membranes that are not performing. 

The look of uncoupling has changed over the years but the basic criterion has remained the same: a configured membrane with open-air space to allow for independent movement between the tile and the substrate. Some of the newest additions to the uncoupling category now incorporate a floor warming system and have an optional integrated sound control and thermal break (for quicker heating reaction time).

The need for a standard

Shear testing an uncoupling membrane in the lab using the Instron machine.


The need for an ANSI standard has become more essential in North America than ever before, with the proliferation of new uncoupling membranes that have emerged in the market recently. The good news is that the Materials and Methods Standards Association (MMSA) has had a subcommittee that has been working on developing a standard now for several years. In fact, a draft standard has been prepared and will be presented at the next Total Solutions Plus (TSP) conference this year being held in Nashville, Tenn., October 26 – 29. Those companies, organizations and associations involved in this effort include: ARDEX Americas, Custom Building Products; ISOLA; LATICRETE; MAPEI; NAC Products; The Noble Company; Schluter Systems, LLC; and TCNA. Most of the details in the TCNA Handbook that were identified earlier will be part of the testing criteria. In addition, “Point Loading” and “Fungus/Microorganism Resistance” will be included. Two additional testing criteria under development are vapor transmission and shears to evaluate the stress/strain relationship between uncoupling membranes and other membranes that are flat. This testing has been an international effort that has displayed some promising results.

Uncoupling membrane in a commercial building.


In addition to the MMSA subcommittee working on an uncoupling standard, the International Organization for Standardization (ISO) has established WG 11 “Uncoupling Membranes for Ceramic Tile Installation” under the auspices of TC-189 (Technical Committee for Ceramic Tile). Some of the same participants are in both committees, so there has been very good communication and collaboration to ultimately achieve the best standards for both organizations. Other areas that are being pursued by the ISO group are “tensile” and “compression” testing.

In summary, uncoupling membranes have come a long way since the introduction of the very first membrane in 1987. Use of these membranes has proliferated over a huge array of substrates and conditions, allowing the tile industry to complete successful installations over some of the most challenging applications. The performance standards for uncoupling have been a long time coming, but creating a suitable standard for a product that works more off of physics than chemistry is not an easy or simple task.  

Uncoupling membrane in a commercial building with large format tile.

Standards and specifications for stone products

Photo courtesy of Continental Cut Stone

When is it appropriate to use natural stone on a project? Many of you are familiar with the TCNA Handbook for Ceramic, Glass and Stone Tile Installation that offers many methods, standards and approved installation methods for both tile and stone. 

There are other standards and specifications that A&D professionals as well as tile and stone contractors would do well to consult when clients are considering stone for a job. Following are excerpts from the “Standards and Specifications for Stone Products” document, originally published in the Dimension Stone Design Manual, Version VIII (May 2016), produced and published by the Natural Stone Institute, in
Oberlin, Ohio. 

The document begins by listing all the standards organizations, which will be abbreviated here with phone and URL in the interest of space. 

It then explains the importance of these standards and how and when they apply, as well as an exploration of the function of the organization and the standards that it provides. It ends with a listing of ASTM standards and specifications that are essential references for specific materials, tests and other factors that affect stone

For detailed information on stone, including additional documents on selecting, working with, and installing natural stone, visit the Natural Stone Institute,


1.1 ASTM International 

Telephone: 610.832.9585 

European Office: 

Telephone: 146.243.7933 

1.2 American National Standards Institute (ANSI) 

Telephone: 212.642.4900 

1.3 NSF International 

Telephone: 734.769.8010 

European Office: 

Telephone: 32.2.771.36.54 

1.4 European Commission for Standardization (CEN) 

Telephone: 32.2.550.08.11 

Photo courtesy of TexaStone Quarries


2.1 In today’s building environment, the emphasis is on safe, permanent, low maintenance products, of which stone leads the list in the minds of architects, designers, and consumers worldwide. 

2.2 Without a consistent, realistic set of standards and testing procedures for stone products, the stone industry as a whole would be in disarray. The standards that have been developed and set in place for these products are important tools to help protect end users, individual companies, and the industry from negative effects related to product failures. Materials standards help to prevent the use of stone products for unsuitable applications. For instance, without the minimum standards for Abrasion Resistance of Stone Subjected to Foot Traffic (ASTM C241), it would be more likely that very soft, easily damaged materials would be installed in commercial applications. This may cause the owner to incur additional cost for repair and maintenance, and negatively affect the reputation of the stone industry as a whole. 

2.3 These standards also serve as benchmarks for quality limits of products. If a stone with a below-minimum flexural strength is used for a lintel, then it may be more likely to fail, thus causing damage and possible injury. Interior or exterior flooring or paving with an inadequate slip resistance level will more likely cause slipping accidents in public or private projects. 


3.1 As stone industry professionals, it is our task to apply the correct standards to materials at appropriate times in order to keep the stone industry strong and to remain a reliable source of quality products. 

3.2 Most architectural specifications require that stone meet certain specified ASTM or other testing standards before it will be accepted for use. Some products on the market today have not been tested for quality standards that are required for certain projects. The required testing should be reviewed and, if test results are not available for the stone product, then testing should be performed by the quarry or representative company as required. Some quarries and their representatives do not embrace this idea because their products can be marketed to homeowners and residential projects without the need to perform testing. It is up to our industry to know how to identify these products and make sure to request the required material data needed. 

3.3 Testing of stone can be performed by other companies in the event that required test data are not available. Independent labs can perform the appropriate tests and provide the information in a well organized, professional report. 

3.4 It is important to know when a certain test is not required for a product. For example, a test for Slip Resistance would not be necessary for stone used in a vertical application, which will never receive foot traffic. Some examples are not as easily established. For instance, what are the needs for testing a stone to be used for interior flooring in a commercial application where the stone is installed over a raised floor deck subject to deflection, and will be subject to traffic from pedestrians and cleaning carts weighing 1,000 pounds? It may be required that the stone of choice meets standards related to Slip Resistance, Abrasion Resistance, Absorption, Compressive Strength, and Bending Strength. These are all physical requirements of the stone product during everyday use. 

3.5 Be aware of the requirements of performance that will be placed on the stone at the time of installation, and in the future. If a stone has proven not to perform for a particular use, then avoid marketing it for that use. If testing is not available, require that it be done or avoid the product’s use. 


4.1 The American Society for Testing and Materials International (ASTM), founded in 1898, is a not-for-profit organization that provides a global forum for the development and publication of voluntary consensus standards for materials, products, systems, and services. Over 30,000 individuals from 100 nations are the members of ASTM International, who are producers, users, consumers, and general interest parties such as government representatives and academicians. 

4.2 Committees are established that focus on and have jurisdiction over standards for different designations, such as Dimension Stone (Committee C18) or Cement (Committee C01). These committees are made up of several subcommittees which are tasked to develop and discuss individual segments within the committee’s jurisdiction. For example, one subcommittee may deal with the development of standards dealing with Test Methods of Dimension Stone, and another with Anchorage Components and Systems for Natural Stone. These committees meet on a regular basis to discuss and present information for each new or existing standard. 

4.3 The entire membership of ASTM International votes on whether a standard is suitably developed and researched before it is forwarded for final approval. Negative votes cast during the balloting process are fully resolved before forwarding. 

4.4 Companies, agencies, and individuals use ASTM standards. Buyers and sellers of materials, products, and services include these standards in contracts; engineers, scientists, architects, and designers use them in their work; government agencies reference them in codes and regulations; and many others refer to them for performance information. 

4.5 ASTM International is recognized globally and continues to review and develop new standards needed in a wide range of materials. 

Photo courtesy of Rugo Stone

5.0 ANSI 

5.1 The American National Standards Institute (ANSI), founded in 1918 by five engineering societies and three government agencies, is a private, not-for-profit organization that administers and coordinates U.S. voluntary standards and conformity assessment activities. The Institute represents the interests of its nearly 1,000 company, organization, government agency, institutional, and international members through its office in New York City and its headquarters in Washington, D.C. 

5.2 ANSI currently provides a forum for over 270 ANSI-accredited standards developers representing approximately 200 distinct organizations in the private and public sectors. These groups work cooperatively to develop voluntary national consensus standards and American National Standards (ANS). 

5.3 The ANSI standardization process provides and promotes standards that withstand scrutiny, yet protect the rights and interests of all participants. This process helps quicken the market acceptance of products, while advising how to improve the safety of those products to protect consumers. 

5.4 U.S. standards are promoted internationally by ANSI. The organization also advocates U.S. policy and technical positions in international and regional standards organizations, as well as supporting the acceptance of international standards as U.S. standards where they meet the needs of the user community. 

5.5 The Institute is active internationally with the International Organization for Standardization (ISO), and, via the U.S. National Committee (USNC), the International Electrotechnical Commission (IEC). In many instances, U.S. standards are taken forward to ISO and IEC through ANSI or the USNC, where they are adopted in whole or in part as international standards. 


6.1 NSF International, formerly the National Sanitation Foundation, is a not-for-profit, non-governmental organization that provides standards, certification, education, and risk management services in the fields of public health safety and the environment. NSF was founded in 1944 in response to a need for a single set of food equipment sanitation standards that manufacturers and operators could accept and regulators could adopt into code. NSF has 21 standards for all types of products and materials used in food service. The standards contain requirements for materials, design, construction, and performance of food service equipment to ensure that it is safe and can be kept sanitary. Today, NSF Food Equipment Standards are globally recognized, and certification to the standards is required by regulators, specified by end users, and marketed by manufacturers. 

6.2 NSF Material Requirements – Standard 51. An important component of the NSF Food Equipment Standards is the material requirements. While each standard can have its own unique material requirements, all food equipment standards reference NSF/ANSI Standard 51-2002, Food Equipment Materials. The material requirements help to ensure that only nontoxic and cleanable materials are used. Material suppliers have utilized NSF Certification to Standard 51 as an effective method for marketing their products to food equipment manufacturers. Manufacturers who purchase NSF-certified materials have one less item of concern when getting their own equipment certified. 

6.3 Applying Standard 51 to Natural Stone. When reviewing granite, marble, and other natural stones to the requirements of Standard 51, there are essentially two issues that can determine its acceptance: smoothness and toxicity. 

6.4 Smoothness. The standard defines “smooth” as free of surface imperfections that are detectable by visual or tactile inspection. This includes pits, cracks, and crevices. This concern for smooth surfaces applies not only to the natural surface, but also the treatments used to make a surface smooth. Application of a coating is sometimes considered a way of addressing smoothness; however, coatings have a tendency to chip or flake over time, thus creating their own difficult-to-clean surface. As a result, there is a prohibition on the use of coatings for surfaces subjected to cutting and chopping actions, such as countertops and cutting boards. It is important to note that this prohibition would not necessarily apply to all surface treatments the natural stone industry might use. Sealers that are buffed off to the point where they only remain to fill surface imperfections are not considered a “coating” for the purposes of NSF standards, and could potentially be used on countertops and cutting boards. 

6.5 Toxicity. Standard 51 requires that materials meet FDA regulations for their intended end use, as specified in the Code of Federal Regulations, Title 21 (21 CFR). Applying Standard 51 toxicity requirements to the stone is fairly easy. Because natural stone does not fall under the scope of 21 CFR, we simply conduct extraction testing to verify that the material does not contain any regulated heavy metals. When sealers are used, NSF must have verification from the sealant manufacturer that it meets 21 CFR. An alternative is that the sealant manufacturer can obtain an NSF certification. 

Copies of each standard can be obtained online or by fax from the source. 

Photo courtesy of Delta Stone Products


7.1 Material Specifications 

7.1.1 ASTM C503, Standard Specification for Marble Dimension Stone (Exterior) 

7.1.2 ASTM C568, Standard Specification for Limestone Dimension Stone 

7.1.3 ASTM C615, Standard Specification for Granite Dimension Stone 

7.1.4 ASTM C616, Standard Specification for Quartz-Based Dimension Stone 

7.1.5 ASTM C629, Standard Specification for Slate Dimension Stone 

7.1.6 ASTM C1526, Standard Specification for Serpentine Dimension Stone 

7.1.7 ASTM C1527, Standard Specification for Travertine Dimension Stone 

7.2 Test Standards 

7.2.1 ASTM C97, Standard Test Method for Absorption and Bulk Specific Gravity of Dimension Stone 

7.2.2 ASTM C99, Standard Test Method for Modulus of Rupture of Dimension Stone 

7.2.3 ASTM C120, Standard Test Method of Flexure Testing of Slate (Modulus of Rupture, Modulus of Elasticity) 

7.2.4 ASTM C121, Standard Test Method for Water Absorption of Slate 

7.2.5 ASTM C170, Standard Test Method for Compressive Strength of Dimension Stone 

7.2.6 ASTM C217, Standard Test Method for Weather Resistance of Slate

7.2.7 ASTM C241, Standard Test Method for Abrasion Resistance of Stone Subjected to Foot Traffic 

7.2.8 ASTM C880, Standard Test Method for Flexural Strength of Dimension Stone 

7.2.9 ASTM C1201, Standard Test Method for Structural Performance of Exterior Dimension Stone Cladding Systems by Uniform Static Air Pressure Difference 

7.2.10 ASTM C1352, Standard Test Method for Flexural Modulus of Elasticity of Dimension Stone 

7.2.11 ASTM C1353, Standard Test Method for Abrasion Resistance of Dimension Stone Subjected to Foot Traffic Using a Rotary Platform Abraser 

7.2.12 ASTM C1354, Standard Test Method for Strength of Individual Stone Anchorages in Dimension Stone 

7.3 Other Application Standards 

7.3.1 ASTM Manual Series: MNL 21. Modern Stone Cladding: Design and Installation of Exterior Dimension Stone Systems. 1995. 

7.3.2 ASTM A666, Standard Specification for Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate, and Flat Bar 

7.3.3 ASTM B221, Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes 

7.3.4 ASTM C36/C36M, Standard Specification for Gypsum Wallboard 

7.3.5 ASTM C91, Standard Specification for Masonry Cement 

7.3.6 ASTM C119, Standard Terminology Relating to Dimension Stone 

7.3.7 ASTM C144, Standard Specification for Aggregate for Masonry Mortar 

7.3.8 ASTM C150, Standard Specification for Portland Cement 

7.3.9 ASTM C207, Standard Specification for Hydrated Lime for Masonry Purposes 

7.3.10 ASTM C270, Standard Specification for Mortar for Unit Masonry 

7.3.11 ASTM C482, Standard Test Method for Bond Strength of Ceramic Tile to Portland Cement Paste 

7.3.12 ASTM C630/C630M, Standard Specification for Water-Resistant Gypsum Backer Board 

7.3.13 ASTM C920, Standard Specification for Elastomeric Joint Sealants 

7.3.14 ASTM C1242, Standard Guide for Selection, Design, and Installation of Exterior Dimension Stone Anchors and Anchoring Systems 

7.3.15 ASTM C1515, Standard Guide for Cleaning of Exterior Dimension Stone, Vertical and Horizontal Surfaces, New or Existing 

7.3.16 ASTM C1528, Standard Guide for Selection of Dimension Stone for Exterior Use 

7.3.17 ASTM C1721, Standard Guide for Petrographic Examination of Dimension Stone 

7.3.18 ASTM C1722, Standard Guide for Repair and Restoration of Dimension Stone 

7.3.19 ASTM E72, Standard Test Methods of Conducting Strength Test of Panels for Building Construction 

7.3.20 ASTM E119, Standard Test Methods for Fire Test for Building Construction 

7.3.21 ASTM E575, Standard Practice for Reporting Data from Structural Tests of Building Constructions, Elements, Connections, and Assemblies 

7.4 ANSI Specifications and Standards 

7.4.1 ANSI A10.20, Safety Requirements for Ceramic Tile, Terrazzo and Marble Work 

7.4.2 ANSI A108, Standards for Installation of Ceramic Tile 

7.4.3 ANSI A118, Specifications for Mortars and Grouts 

7.5 NSF/ANSI Specifications and Standards 

7.5.1 NSF/ANSI Standard 51, Food Equipment Materials 

7.6 CEN Specifications and Standards 

7.6.1 CEN specifications and standards are in the process of being compiled. This information will be available at a later date. 

All standards and specifications are revised or updated periodically. The current status of any standard or specification can be confirmed by contacting the proper authority.

Photo courtesy of TAB India

The changing market for ceramic tile in the USA

Donato Grosser’s Coverings presentation looks at the sales patterns for independent distributors

Donato Grosser, principal of D. Grosser and Associates, Ltd.

As part of the conference program at Coverings 19, Donato Grosser, principal of D. Grosser and Associates, Ltd., in New York, offered an analysis of ceramic tile business in the U.S., based on interviews with distributors in Florida, Southern states (Tennessee, Georgia, Alabama, Arkansas, Mississippi, Louisiana, Carolinas), Texas, the Southwest (Arizona, Utah, Nevada, Colorado, New Mexico), California, the Northwest (Oregon, Washington), the Midwest (Ohio, Michigan, Illinois, Wisconsin, Minnesota), New England, New York, New Jersey, and the Middle Atlantic (Maryland, Pennsylvania, Virginia).

The overall findings, targeted to inform independent distributors, show that though there was a strong market increase from 2012 to 2017, a slowdown occurred in 2018. The strength of suppliers like MSI, Emser, Floor & Décor have negatively impacted independent distributor business. Other factors in sales slowdowns are the strengthening of luxury vinyl tile (LVT) and Chinese competition, as well as high cost of installation. The bright spots in Grosser’s report were that remodeling kept distributors in business during the recession, and areas with high birth rates and low taxes and immigration are the strongest economically.

Number of distributors shrinks; big companies get bigger

Grosser’s research shows that although there were 21,725 ceramic tile contractors and dealers in the U.S. in 2008, now that number has plummeted to only 16, 406 in 2018, with a slight swell expected to 16, 806 in 2019. 

These trends run inverse to U.S. ceramic tile consumption, which was at a high of 3,315 million of square feet (m. sq. ft) in 2006, and dropped to only 1,959 m. sq. ft. in 2009. It has slowly increased to an expected 3,170 m. sq. ft. in 2019. Consumption was nearly flat from 2017 at 3,046 m. sq. ft. to 3,107 m. sq. ft. in 2018. 

Overall, Grosser reported that the number of distribution outlets are declining, the number of ceramic tile distributors has fallen from a high of 1,376 in 2014 to a low of 1,241 today. The big are getting bigger and the small are getting smaller, with large distributors expanding and small distributors shrinking. In terms of ceramic tile sales, 2018 was nearly flat, and the growth of LVT as well as flat residential construction will keep sales low in 2019 as well, Grosser predicted. 

Total U.S. manufacturing capacity is now about 1,204 m. sq. ft., with usage of manufacturing capacity at about 80%:

  • Dal-Tile: ~613 m. sq. ft.
  • Italian plants (Stonepeak, Florim, Florida Tile, Del Conca, Landmark): ~430 m. sq. ft.
  • Other main manufacturers: 161 m. sq. ft.

Regional synopsis

Here’s a synopsis of distributor activity according to region. 

Florida – After lows in 2009, sales spiked 60% in 2012-2014, with a 2017 boom for some distributors due to residential and commercial construction. Currently, most sales are for remodeling and commercial construction. Some distributors are exporting to Caribbean islands. Hurricanes turned out to be a mixed bag: sales were lost for a month, but then sales to fix storm damage surged. Negatives include an oil spill in the Panhandle in 2010, Chinese competition, and flat sales from 2017 to 2018 due to competition by Floor & Décor, MSI and Emser.

Southern states – Sales have improved across the South since 2013. In Tennessee, some distributors report a boom; others complain of sales lost to LVT. Sales are up in Georgia, and booming sales in Alabama credit high-end residential and new commercial projects. Arkansas is enjoying a boom; healthy sales in Mississippi and Louisiana are up 10-15%, and sales in the Carolinas are flat to 15% up. 

Texas Though there was a slowdown at the end of 2018 – which some companies attributed to the mid-term elections – many companies have reported sales gains of 15-20% per year since 2014. Commercial construction, hospitality and remodeling are abundant; sales are surging in Houston due to remodeling after hurricanes. 

Southwest – New construction in residential, hospitality and restaurants is contributing to 20-30% boom conditions in parts of Arizona, especially in Phoenix. Utah is seeing sales rise 7-20% due to rise in multi-unit residential projects, mid-to-high-end residential and commercial construction. 2018 sales are up in Nevada 10-20% due to new construction and residential remodeling, though LVT is impacting tile sales as builders embrace LVT. Colorado is reporting sales increases across the board, especially in the Denver area and suburbs where high-end residential construction and new commercial construction are going strong. In New Mexico, one distributor reported 10% sales gains last year due to mid-to-high-end residential construction and new retail and hospitality construction; another distributor said he was impacted by loss of government money in the region. New construction is strong for healthcare projects.

California – The Golden State has enjoyed steady growth from 2010 to 2018, though the rate has slowed in the last six months. Bright spots are growing sales in tile slabs, large importers selling to tract housing developers and small and medium distributors supplying remodeling efforts. The interest in low-cost Chinese tile is being felt in this state. 

Midwest – After sales bottomed out in 2008-2009, Ohio distributors saw sales surge up to 20% 2013-2016, mostly for residential remodeling. Last year sales were up for commercial projects, retail, institutional and offices. Michigan saw similar growth over those years due to new hospitality and office construction, and high-and-mid-level residential, with 60% sales due to remodeling. 2018 saw a slight slowdown. Illinois saw 15-20% growth per year 2012-2018 in residential remodeling or multi-unit construction until a slowdown in 2018. Post-tornado sales in 2015 soared. Tiles are mainly used in bathrooms and some kitchens, fighting competition from wood flooring. Wisconsin is a mixed bag with some reports of booming 30% sales increases from 2017 due to high-end residential, remodeling and new commercial building; others saw sales are down due to competition from VCT and LVT. Minnesota distributors saw yearly increases of 10-20% from 2012-2016; in 2018, some reported 10% hikes, while others said installation costs are negatively impacting tile sales and one distributor said sales fell 20% due to customers switching to LVT. 

Northwest – Sales in Oregon last year spiked 5-15%, with residential construction doing well; some distributors reveal that remodeling makes up 50% of sales. In Washington, recovery began in 2013; between 2016-2018 new high-end residential and retail projects pumped up sales 10% each year. 

New England Sales were mostly flat for 2018, declining in the second half of the year. New high-end residential and commercial fueled sales, but some distributors say companies are leaving Connecticut due to high taxes and the recently-instituted $10,000 cap on state and local taxes (SALT) that taxpayers can claim on their federal income taxes. 

New York – Though sales surged in the wake of Hurricane Sandy, 2018 was mostly flat in the area, except in high-end Manhattan apartments and suburban areas with high birth rates that spurred residential remodeling. Big-box competition, internet sales, and exodus of people to the South and West are depressing sales in the region. 

New Jersey – 2018 was stellar for many companies, though sales fell after August and some companies are reporting flat sales, depressed by competition from Floor & Décor and similar stores and high installation costs that spurred a switch over to LVT products. Sales health was found in new commercial building and residential remodeling.

Mid-AtlanticSales were down or flat in Virginia and Pennsylvania (except for an increase from 2011 to 2018 in Pittsburgh); Maryland is expecting an increase in the first quarter with most companies reporting 5-15% increase due to healthy mid-to-high-end residential and commercial, except in areas where construction is down. 

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