Eldorado Stone, a Boral brand, introduces a new color palette to accentuate the classically-inspired aesthetics of one of its most popular profiles. As more nuanced, up-to-date design options remain in high demand from project specifiers, the innovative multilayered color notes in Loire Valley™ RoughCut® artfully blend contemporary hues with classic, nature-inspired textures to enhance residential and commercial spaces.
“There has been an increased interest in classic looks with a contemporary twist, so we created this new color palette to refresh one of our most time-honored profiles,” said Sarah Lograsso, Director of Marketing. “With the introduction of Loire Valley RoughCut, specifiers can now incorporate a fresh new color into their projects while still embracing more traditional stone surfaces.”
Inspired by the French countryside after which
it derives its name, Loire Valley RoughCut presents a sophisticated
gradient of ivories and muted creams with touches of sand and rust. The
bold, hand-formed shapes of RoughCut incorporate embedded, fossilized
artifacts on a roughly cleaved, pronounced face to mimic the character
According to Remodeling Magazine, manufactured stone
provides one of the highest return values of any material.
Incorporating stone veneer into interior and exterior projects is a more
cost-effective and higher quality finish than many other materials. An
exterior façade made with manufactured stone veneer can enhance curb
appeal and potentially increase home value, while using stone indoors
can create a distinctive space that blends natural world elements with
Mother Nature has always provided the strongest and most artistic designs imaginable. Antolini has over 60 years of experience harnessing this natural power allowing us to revel in our world’s innate elegance. New to Antolini’s lineup is the Exclusive Stone: Crema Cielo.
Allow yourself to be enamoured by Crema Cielo’s captivating presence in this interior design. This marble is revolutionary to the divine setting, capturing the fine details of this stone. As the room transcends into a delicate and contemporary union, Antolini has perfected Haute Nature in any design.
The cascading delicate and soft hues descend sinuously and create an admirable kinship throughout the surface of this fine marble. The fluent Crema Cielo enhances the spaces and gives a sense of lightness and spontaneity thanks to the wavy streams that allow a constantly evolving smooth shape.
Oberlin, OH, January 14, 2020—The Natural Stone Institute and Stone World magazine are pleased to announce the schedule for the 2020 Stone Industry Education Series. Stone Summits will be held in nine cities across the United States.
The nine Stone Summits scheduled for 2020 will cover topics relevant to stone fabricators, including maximizing shop efficiency and profits, using metrics to measure success, understanding OSHA safety regulations, and creating a plan for finding and retaining top talent. 2020 Stone Summits will be facilitated by a team of experienced industry leaders including GK Naquin, Duane Naquin, Tony Malisani, and Eric Tryon.
2020 Stone Industry Education Series:
Arkansas Stone Summit: 12 Business Axioms
Pacific Shore Stones
California Stone Summit: Stone Shop Management
Colorado Stone Summit: Know Your Business
Massachusetts Stone Summit: Key Pulse Points for Building a Successful Stone Fabrication Business
New Mexico Stone Summit: Key Pulse Points for Building a Successful Stone Fabrication Business
Oberlin, OH, November 20, 2019—The Natural Stone Institute, in coordination with the National Building Granite Quarries Association (NBGQA), has added three toolbox talks for quarriers to the Natural Stone University. Topics include the following:
Fall Arrest System Regulations
Highwall Management and Use of Drones
Quarry Slab Tipping Safety
There are now a total of 27 quarry-specific toolbox talks available in the University, covering topics ranging from personal health and human safety to the safe use of equipment such as wire saws and preventing silicosis.
The Natural Stone Institute, in coordination with the National Building Granite Quarries Association (NBGQA), has added three toolbox talks for quarriers to the Natural Stone University.
Mike Loflin, Industry Research & Information Manager for the Natural Stone Institute commented: “These quarry-specific resources are an important addition to our library of safety resources. The information provided is the cumulative work of the NBGQA safety committee. The NBGQA safety committee consists of some of the most talented safety officers, operations managers, and human resources professionals in the natural stone industry. Over the last several years, the committee has identified issues and provided seriously needed safety solutions for the quarry sector of the dimension stone industry. We are proud to partner with NBGQA to present these resources free of charge to the industry through the Natural Stone University.”
To access these toolbox talks and other educational resources, visit www.uofstone.org. To learn more about the National Building Granite Quarries Association, visit www.nbgqa.com.
When working with natural stone, all the rules you know about porcelain tile can be immediately discarded. It’s imperative to know the stone, know the finish, know about the stain, and know what you are getting into. What works for porcelain tile does not necessarily apply when working with products created 100% by Mother Nature.
The Natural Stone Institute states that natural stone can be classified into two general categories according to its composition: siliceous stone or calcareous stone.
Understanding the key differences between these can help avoid costly damage to the product and to your reputation as a knowledgeable contractor!
Types of stones
Acid etching in Veona Rosso.
Calcareous stone is composed mainly of calcium carbonate. These stones include marble, travertine, limestone and onyx and can be classified as acid-sensitive. They are sensitive to acidic substances such as coffee, lemon juice, vinegar, and bleach, all of which can very often leave a natural stone surface etched.
Common sense dictates that by using acidic cleaning products, acid-sensitive stones could very well become damaged. Therefore, these stones should ONLY be cleaned with a neutral cleaner! Before applying any product, always test it on a section of stone not being used, or an area that will not be in plain sight.
Etching on marble counter.
Non-calcareous (siliceous) stone is composed mainly of silica or quartz-like particles. Types of non-calcareous stones include granite, slate, sandstone and quartzite. For the most part, these stones tend to be very durable and most are acid-resistant. Be advised, some of the more exotic stones have veins of calcium calcite, which can make them acid-sensitive. Whereas acid-resistant stones can generally be cleaned like porcelain tiles, I recommend to always test first via the small aforementioned exercise.
Now that you know your stone, let’s discuss the surface finish of acid-sensitive stones.
Honed finishes on acid-sensitive stones can withstand alkaline cleaners.
Polished acid-sensitive finishes can be dulled by strong
alkalines; again neutral cleaners are the best option.
Testing is ALWAYS your best option.
Removing stains without harming the stone
Rust stains on marble.
Let’s review a few types of stains. Identifying the type of stain on the surface is the key to ultimately removing it without harming the stone. Refer to the manufacturer labels when choosing the right cleaner for your stone and the stain.
Organic stains: These are caused by organic products such as fruit, tea, dirt, leaves, wine, cooking oil, and even animal droppings. Other stains can occur due to the growth of fungi, algae, mildew and other microorganisms. Generally speaking, these types of stains appear on outdoor pavers or inside a bathroom/shower stall and other wet areas.
Carrara marble with rust.
Inorganic stains: Paint, cementitious grouts, cements, rust, soap scum and other non-organic sources can cause serious staining to natural stone features, especially if not cleaned up quickly.
Preventing and removing grout haze
Last, let’s discuss grout haze on natural stone. One of the top, vexing problems is cementitious grout haze on acid-sensitive stones.
How do we prevent grout haze on acid-sensitive stones? The only way is to always seal the stone, BEFORE grouting. This is a vital, cardinal rule – always seal an acid-sensitive stone before grouting. The use of a normal sealer will suffice.
Cement residue on stone.
What do you do if grout haze does appear on an acid-sensitive stone? Here, we need to work with a neutral cleaner and the mechanical action of scrubbing. Scrubbing is important. If the stone has a natural finish or is honed, you can use an alkaline cleaner to remove an epoxy residue.
Before and after marble cleaning.
From granites to limestone, from marbles to slate, Mother Nature has truly created some of the most beautiful surfacing material on our planet. We’ve pulled it from the earth and brought it to life through exquisite tiles and slabs, which adorn our floors and walls across the globe. Keeping stone material in its most beautiful state takes just a few simple steps to understand what you are working with, and then learning the proper protocols to bring them back to that beautiful condition. Taking simple steps to read the recommendations, using the right products and not skipping any steps in doing so can ultimately mean that customers are happy, there will be more money in your pocket, and chances to be called back on a regular basis are optimized.
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
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, www.naturalstoneinstitute.org.
2.0 WHY ASTM STANDARDS AND OTHER LIKE STANDARDS ARE IMPORTANT
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.
3.0 HOW AND WHEN THESE STANDARDS APPLY
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.
4.0 ASTM INTERNATIONAL
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
5.1 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.
6.0 NSF INTERNATIONAL
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.
6.4Smoothness. 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
7.0 ASTM SPECIFICATIONS AND STANDARDS
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.
Oberlin, OH, March 27, 2019—The National Institute for Occupational Safety and Health (NIOSH) will be hosting a free silica safety webinar on Tuesday, May 14 at 11am PST. Designed for stone countertop fabrication employers, the webinar will describe the dangers of silica exposure, outline employer requirements to comply with OSHA’s Respirable Crystalline Silica Rule, and offer methods employers can use to protect workers.
During the webinar, representatives from OSHA, NIOSH, and the California Department of Public Health will provide information related to silica exposure, including health risks, methods to protect employees from silica dust, and OSHA requirements. Two Natural Stone Institute Accredited members, Jonathan Mitnick (CCS Stone) and David Scott (Slabworks of Montana) will provide practical tips on controlling worker exposure to silica dust and share the steps they took to ensure their shops were OSHA compliant.
Mark Meriaux, Accreditation and Technical Manager for the Natural Stone Institute commented: “It is important for fabricators to comprehend the health risks involved with silicosis, both personally and for employees, and to understand what can be done to minimize the risks. There is currently at least one documented case of silicosis in California tied to a fabrication shop, so now is the time to get this message out to fabricators. We look forward to working with NIOSH to share this message.”
For this month’s Stone section, we take a look at stone showers completed by NTCA members Hawthorne Tile in Portland, Ore., and RMZ Custom Tile and Stone in Avon, Colo.
Hawthorne Tile Lake Oswego master bath
This gorgeous master bath project for a Lake Oswego, Ore., residence was part of a three-month, full-home remodel, with extensive limestone used throughout, sourced from Artistic Tile. Due to hydronic heating in the home, the Hawthorne team set 150 ft. of 5/8” x 5/8” Whirlwind Smoke limestone floors to RH 141 in the TCNA Handbook.
Shon Parker (now with Schluter) was the project manager on the job, and admitted that widespread leveling was required prior to installation due to the wood substrate. “It gave us a chance to get the floors flat and do a barrier-free shower,” he said.
In that shower, the crew employed the B442-18 integrated bonding flange method from the TCNA Handbook, with Schluter bonding flange and tileable cover. ARDEX 8+9 was used as waterproofing and crack isolation with Schluter Schiene strip. Wall tile was set over cement backer, also with Ardex 8+9. Another challenge in the shower was managing the incredibly fragile two-color limestone pattern – Artistic’s Smoke Limestone Claridges Stone Water Jet Mosaic. Parker said that Portland Marble Works – the fabricator who was doing the slab counters – waterjet-cut the inside corners “to keep the fine points of the tile from breaking on a wet saw,” according to the paper templates the crew created for all floor and wall cuts. Parker said Hawthorne Tile opted for the paper templates because the tile pattern was a unique shape. “The templates helped make perfect cuts each time, which helped the waste factor on such an expensive tile,” he explained. For the shower floor, the crew installed 130 feet of Lycian Aperlae Turkish Marble.
The project, which had ceilings that ranged from 8’ high to 14’ at the high end of the vault, also sported 6” x 8” limestone tile wainscot everywhere in the bath except the shower, to complete the look of the room.
RMZ Custom Tile stone wave mosaic shower
The design of a stone wave mosaic in a shower install by Miguel Ramirez of RMZ Custom Tile mandated extreme precision on the wall prep. “One of the challenges was to get the wall prep perfectly plumb and flat since on that particular wave tile every corner had to match the return piece perfectly,” he explained.
“One of the things that we had to do prior to installation was to lay every row for the entire shower flat and mark every wall where the cut was going to be to have accurate piece return and continuation,” he added. “That was the most challenge that we had, since we were using the drop cut as a return.”
The marble mosaic project consisted of about 180 sq. ft. of First Snow Wave Mosaic by Daltile.
“For leveling I started with the framing, making it as true as possible, then added shims,” Ramirez said. “I also used wedi panels as a substrate.” Afterwards, using a straight edge, he applied a final coat of Custom Building Products’ ProLite mortar where needed to make sure the surfaces were flat and plumb. He used the same mortar to install the stone, with a coat of StoneTech Impregnator Pro sealer applied before grouting with Custom’s Prism Grout. After the grout cured for a minimum of 72 hours, he applied another coat of sealer, and voila! A beautiful stone shower!
An ongoing issue with stone shower installations is that sometimes stone showers mysteriously discolor or appear to not drain. There are various conditions and situations when this appears, and a range of explanations why this happens.
Recently a NTCA Five-Star Contractor had a problem with a Calacatta marble tile shower, installed with 4” x 4” tileable drains, utilizing a topical waterproof membrane system. The contractor reported that the waterproofing used is not leaking, the slope is done according to code and the thin-set mortar was chosen appropriately for the installation system and white marble. These topical membrane systems and drain assemblies are sometimes used in lieu of a traditional mortar bed shower pan application with weep holes.
The contractor contacted the manufacturer rep as well as the tile supplier, asking, “We are wondering if the water infiltrates the white marble from the exposed edges around the drain enclosures, and because of its porous nature, and because of the waterproofing underneath, it is taking much longer to dry.”
Mark Heinlein, NTCA Training Director, enlisted the help of other industry experts to provide an answer, as well as giving his expert opinion.
“There is indeed concern in the tile industry regarding the situation you described,” Heinlein said. “The NTCA’s Technical Committee has been giving this issue serious consideration and has appointed a subcommittee to gather data in an attempt to quantify and hopefully identify the nature of the problem. To help me respond to your question, I have addressed Mr. Martin Brookes and Mr. Steve Young, who have been the persons actively pursuing the causes of this issue.”
Martin Brookes, of NTCA Five-Star Contractor Heritage Tile and Marble in Mill Valley, Calif., offered these thoughts: “The problem with this type of shower pan assembly is that there is no accommodation for a weep system and all water is evacuated topically. This in turn could create a problem around the drain with light colored stones or transparent tile,” he said. “The moisture can’t evacuate like a traditional water-in/water-out shower pan liner with a weep system. In addition, since the stone material is directly bonded to the membrane, allowing no room for error in the installation process, water can pool under the tile especially if the ridges are not fully collapsed. It is my opinion that ifthis type of system is used with the light colored stones or transparent tile, proper slope, mortar coverage and troweling techniques must be used to prevent any water accumulating underneath the tile surface.” Steve Young of Steve Young & Associates, White Plain, Ga., concurred.
Heinlein provided the contractor with documentation they could present to the client to address a similar problem on other showers on a current project.
“Page 252 of the 2018 NTCA Reference Manual is a sample letter (with photos) to prospective clients regarding this matter,” Heinlein said. “I have also spoken with James Woelfel, Chairman of the NTCA’s Technical Committee. James concurs with Martin’s assessment in that it is likely the troweled mortar ridges under the tile on the pan are not fully collapsed. This allows water to run under the tile through the bond coat and on top of the waterproofing membrane until it hits the drain assembly, where it then begins to pool in the uncollapsed ridges and is further absorbed by the tile. Additionally, there are some concerns that the stone could be sourced from quarries around the world and may be a similar species as Calacatta Marble, but may not have the same properties as Calacatta Marble.”
The contractor was elated at the information and solution to the mystery. “Thanks so much all!” she said. “We are so grateful to have such accessible expert resources!”
The Natural Stone Institute has announced a year-long partnership with Architectural Record to present the Natural Stone Academy, an interactive continuing education platform featuring articles and webinars about natural stone. Architects, designers, and stone industry professionals can take courses in the Academy to earn CEU credits. Individuals who complete all courses will receive a special badge.
There are seven courses available in the Natural Stone Academy, covering the following topics: anchorage systems for natural stone cladding, specifying natural stone, residential design, landmark design, design strategies, the enduring allure of working with natural stone, and the NSC 373 sustainability standard.
Since launching in September, over 1,500 individuals have completed courses through the Natural Stone Academy.
The Natural Stone Institute would like to thank the following companies who have sponsored this program: Alamo Stone, Camarata Masonry Systems, Ltd., Coldspring, Egymar International, International Marble Company, LLC, Lurvey Supply, North Carolina Granite Corporation, PICCO Engineering, Polycor, Raducz Stone Corporation, and Rugo Stone LLC.