Natural stone tile continues to grow in popularity despite reduced consumption due to the soft economy. Materials used to install these tiles continue to change. As products and their usage change, so must you change to stay current with industry standards and the manufacturer-recommended applications of these products.

Shrinkage is not new. In fact, it’s expected to occur within setting materials. What has changed is that much more stone is being installed today, over different substrates and substrate conditions For instance, crack-isolation membranes – rare years ago – are much more common today. There are also a variety of membrane types with different properties and requirements.

Also, installers today tend to use much thicker application of thin-set mortar to compensate for irregular substrates, instead of correcting the substrates’ irregularities before installing tile. There are many more polymer/latex-modified thin-set mortars being used now rather than the standard dry-set thin-set mortars. All of these changes produce shrinkage and less resistance to shrinkage, resulting in a condition in stone known as “indent fractures.”

The phenomenon of indent fractures is much more frequent today. An indent fracture is a spider web-like fissure typically found in softer stones such as limestone and travertine, but is also seen in marbles and even some granites. It typically runs through one or more tiles and will branch off in different directions. Indent fractures are not easy to see; typically they can only be seen from an angle when light reflects off them. If you run your hand over the indent fracture you can’t feel it because there isn’t an actual crack or separation in the stone surface. If you put a straight edge over the indent fracture and shine a flashlight from the back of the straight edge, the light shines through at the fracture, indicating a low spot. Indent fractures can develop into an actual crack separation if the stone is subjected to enough movement, stress from deflection, or due to lack of movement joints.

The culprit

I have investigated numerous stone tile applications with this indent-fracture condition. The common denominators in each case are typically excessively-thick, polymer-modified thin-set mortar installed over a membrane of some sort. It also occurs where a bonded mortar bed wasn’t bonded to its substrate and was applied very wet and rich and in cases where the wire reinforcement for a non-bonded mortar bed was at the bottom of the mortar bed rather than suspended within the mortar bed.

What we found in our investigations was that the combination of excessively-thick thin-set mortar over a resilient membrane allowed the indent fracture to occur. The total force of shrinkage resulting from thicker applications of thin-set mortar will impart greater stresses in the stone than a thinner application, causing more deformation (strain) or shrinkage. This is compounded if the thin-set is also installed over a resilient membrane, because the membrane isn’t as effective in restraining the thin-set mortar as a rigid concrete substrate would. Instead, the thin-set mortar under the stone dries in a manner similar to a dry lake bed, with compression within some areas of the thin-set that results in tension in other areas, creating cracking in the thin-set. The crack then works its way up through some of the stone, but does not appear as a crack at the surface.

This condition is further compounded when a stone is installed over a membrane, since the moisture within the thin-set mortar can’t be absorbed by the substrate. The moisture can only escape through the stone or the grout joints. Of course the thicker the thin-set, the more moisture the stone is subjected to. This causes it to expand, resulting in more stress and deformation.

Wet-set mortar

Indent fracturing can occur when tile is installed over a wet-set mortar bed application particularly if it is over fat mud (very wet) which creates much more shrinkage, particularly if the mortar mix is very rich (higher ratio of cement to sand). If the mortar is placed over a membrane, as the mortar shrinks the membrane isn’t restraining the shrinkage. If the membrane isn’t properly attached to its substrate then it can further reduce the amount of resistance on the mortar bed or the thin-set. On a non-bonded mortar bed over cleavage membrane, wire reinforcement is required to minimize the shrinkage. If the wire reinforcement is left out or placed at the bottom of the mortar bed, then it can’t do its job of mitigating shrinkage and avoiding indent fractures. Dry-pack mortar has very little moisture for the stone to absorb, so shrinkage is much less.

Recently I was involved in devising some experiments to reproduce indent fracturing in a testing laboratory. We substantiated that the thicker application of thin-set mortar created more stress and strain, and application over a resilient membrane contributed to deformation by not fully restraining the thin-set as it would if bonded to a rigid surface. It was determined that the fractures were the result of tension within the thin-set mortar at those points.

Indent fractures didn’t develop right away, but took a week or more to develop and eventually halted. Cracking initiated within the thin-set and traveled up through the bottom of the tile. Based on Pythagorean triangular geometry, an indent can be explained by the bottom of the stone shortening from deformation caused by the thin-set shrinkage, resulting in the crack. The top surface of the stone is drawn down at the crack location resulting in the indent (low point).

Avoiding indent fractures

So what can you do to avoid indent fractures? First, follow thin-set mortar manufacturers’ recommendations for their products. ANSI now has defined the differences between a medium-bed and thin-bed thin-set mortar, indicating their limitations. A thin-bed mortar cannot be used any thicker than 1/4” or less than 3/32” after the tile is embedded. A medium-bed mortar cannot be any thicker than 3/4” thick after the tile is embedded. ANSI further states that the medium-bed mortar is not intended to be used in truing or leveling underlying substrates or the work of others, but only to accommodate the irregularities within a tile.

Make sure you adjust your substrate to meet ANSI A108 flatness requirements. Then use thin-bed mortar, limiting the thickness to 1/4.” Use a rapid-setting thin-set to help minimize the extent of shrinkage since it cures faster. A membrane with less resilience can also help to restrain the thin-set mortar if it is properly attached. Use dry-pack mortars for wet-setting stone on floors to limit the amount of shrinkage and the amount of moisture to which the stone is subjected. Make sure your wire reinforcement is suspended within one-third to one-half the thickness of the mortar bed for non-bonded applications to help minimize shrinkage.

Bottom line: if you want to avoid problems, follow industry standards.

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Ceramic Tile Consultant, Donato Pompo CTC CSI CDT MBA is the founder of Ceramic Tile and Stone Consultants (CTaSC). Donato has over 30 years of experience in the ceramic tile and stone industry from installation to distribution to manufacturing of installation products. CTaSC provides services in forensic failure investigations, quality control for products and installation methods, including writing specifications, training programs, testing, and on-site quality control inspection services. CTaSC is a professional consulting company comprised of expert tile and stone consultants, accomplished ceramic tile and stone installers, architects, engineers, general contractors, construction scientists and other industry specialists conveniently located throughout the US and Canada. Reach Donato at www.CTaSC.com or e-mail at Donato@CTaSC.com or by calling 866-669-1550.

There is a new sheriff in town and his name is ISO – ISO 13007 to be precise. Does this mean that the old sheriff (U.S.A. industry standard ANSI A118) is dead and gone, replaced by a new world order?

Not on your life!

ANSI hasn’t gone anywhere and in my opinion never will. But this new addition to the Tile Council of North America Handbook for Ceramic, Glass, and Stone Tile Installation has much to offer in the way of helping architects and design professionals write more precise specifications that will help reduce the risk of tile and stone installation failures. The following list of Q&A’s might help explain why.

What does ISO stand for anyway? The International Organization for Standardization is a worldwide federation of standards bodies with a strong European influence.

Are the ISO test methods the same as what ANSI uses? No, not even close. ANSI’s primary focus is on tile-to-tile shear-bond strength. ISO uses primarily concrete-to-tile tensile bond strength tests. Shear testing is for measuring lateral stress; tensile is for vertical. ANSI measures in pounds per square inch (psi); ISO measures in Newtons per millimeter squared (1N/mm2 =’s 145 psi ).

Which one is best? Can’t answer that! Both are vitally important. When concrete cracks or expands, a lateral stress comes in to play. When floors bounce (deflect) such as upper levels of shopping malls, vertical stress is applied. When floors heat up from sunlight through windows or skylights, both directions of stress can adversely affect a tile installation.

How are they similar? Wish you wouldn’t have asked that question. There is no simple one-sentence (or even 100-sentence) answer, but I’ll do my best in this limited space. Both standards measure a thin-set mortar’s performance levels. Both have two tiered levels of performance; ANSI has A118.1/A118.4 and ISO has C1/C2. Both take into consideration open times, water immersion, freeze/thaw, and room temperature aging. Additional or optional characteristics include fast-set, extended open times, and non-slip. Both standards also have special thin-set mortar categories for installations over plywood: ANSI A118.11 and the ISO P rating.

What about standards for installation products other than thin-set mortars? For mastics, ANSI has A136.1 and ISO has a D classification for Dispersion Adhesives. For epoxies ANSI has A118.3 and ISO has R classification for Resin Reaction Adhesives. ANSI covers cementitious grouts in A118.6 and A118.7 standards; ISO in CG1 and CG2 standards. Also, ISO 13006 is a standard for ceramic tile as is ANSI A137.1

So, with this new wealth of knowledge I now possess, how can I use the ISO standards to help reduce the risk of failures for my tile installations? Not so fast! You don’t know enough yet. You have not asked the right question, which is “Besides testing procedures, how is ISO different?” I have a threefold answer to that question; heat resistance, substrate considerations, and deformability of mortars.

The thermal-shock testing (heat aging) in ISO testing closely simulates what happens to tile installations near windows or skylights where the tile and substrate materials all expand and contract frequently and at rapid rates.

The standard substrate in all mortar testing in ISO is concrete while ANSI shear tests are always tile-to-tile.

Lastly, and most importantly, is deformability. Transverse deformation, denoted as “S” in ISO is the ability of a mortar to accommodate vertical movement or expansion between the tile and the substrate. Put more simply, any mortar with an S classification denotes how much a thin-set mortar will bend before it breaks. This adds a new dimension to evaluating installation products.

  
Both of these failures could have been avoided with more precise ISO and ANSI mortar specifications.

Summary
In my opinion, neither standard by itself gives a specifier all the information that is now available. There is much more to consider because there is now much more that is known. Because of the new information that ISO provides, written specifications in conjunction with the information in ANSI can be more precise because it is now easier to identify and match important characteristics of mortars to specific conditions on projects.

I’ll give you a couple of examples. Say you need to install 12″x12″ porcelain tiles on the second floor of a shopping mall. I would recommend ANSI A-118.4 and ISO C2S2E for the thin-set mortar. How about quarry tile on new slab-on- grade concrete? You could save money and still sleep at night by specifying ANSI A-118.1 and ISO C1. I personally sleep very well at night because I have eliminated ANSI A-118.1 and ISO C1 from my vocabulary, but that’s just me. I like the latex contents found in A-118.4 and C2!

I have always felt that the shear/bond performance ratings for A118.4 mortars are much too broad. An A118.4 porcelain-tile minimum-shear bond requirement is only 200 psi and yet there are many 700+ psi products on the market, but ANSI has no mechanism to differentiate between them. We know for a fact that many manufacturers are building-in a fair amount of flex into some of their products, but there is no way to measure the horizontal flexibility capabilities with ANSI; at least not in A-118.4. A-118.12 has a horizontal shear/bond stretch test for crack isolation membranes, but the 50 psi requirement is too low for mortars. Maybe this could be expanded upon some day. As a ceramic tile consultant who has investigated hundreds of thin-set-on-concrete tile failures through the years, I think a workable lateral- shear flexibility (deformability) test for mortars could possibly become the most relevant test of all.

Neither one of these standards is perfect in and by itself, but together many performance characteristics can be ascertained. For example, if an ISO C2S2 mortar has excellent stretch capabilities on a vertical tensile strength test, it’s logical that it would do very well absorbing lateral-shear stress as well. Conversely, if an ANSI mortar has enough adhesive bond strength to score high on an ANSI porcelain tile shear strength test, it’s likely that it’s also quite flexible and would do well with ISO’s deformability testing. Wouldn’t it be great if ISO and ANSI could come together more?

The Tile Council of North America’s Handbook does a great job of giving choices and minimum recommendations for material performance levels, but it is up to the specification writers to make the final determinations. ISO 13007, the new international sheriff in town, can be partnered up with the “good ol’ boy ANSI sheriff” from the USA to help reduce the risk of ceramic tile failures by more closely defining thin-set mortar performance characteristics. In other words, let ISO and ANSI be your guides.

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Tom D. Lynch is a 49 year veteran of the ceramic tile industry with an installer, contractor and technical services background. Find him on the web at tomlynchconsultant.com

One of the hottest trends seen at the Cersaie show in Italy and Cevisama in Spain is the emergence of thin tiles. These thin tiles start at thicknesses of about 2.5 mm for walls up to about 6 mm thick for floors. Manufacturers tout a range of advantages, including installation over existing floor or wall coverings, eliminating the need for ripping out existing finishing materials in renovation projects, saving time and money in labor costs. The tiles are strong and lightweight, and reduce material consumption which benefits the environment. They can also be easily cut with a wet saw, and in some cases (easier with non-reinforced slabs) with a glass cutter.

According to Eric Astrachan, executive director of the Tile Council of North America (TCNA) there are currently three technologies used to manufacture thin tile: the Lamina process using Italian-made System equipment (System itself manufactures Laminam tiles); the Continua process using the Italian-made Sacmi equipment; and double-pressed or dust-pressed technology that loads powder into the press to produce a thin tile.

Typically, Lamina-made tiles are 3mm thick – largest slabs being 1000×3000 mm and 1200×3600 mm in size; Continua process tiles are equal or greater than 3 mm thick for walls and equal or greater than 4.6 mm thick for floors; dust-pressed tiles typically are 4.8mm thick, and not less than 4.5 mm thick. Most of these processes can be available with or without reinforcing mesh on the back.

Standards: in development

In terms of thin-tile installation, Astrachan said, “There are no nationally-recognized installation standards for thin tiles anywhere in the world of which we are aware. This is a problem because opinions abound on how to install it, and failures have resulted.”

Efforts to develop ISO standards for thin tile and installation standards are afoot, and TCNA is working in conjunction with the international body to provide input. TCNA is also collaborating with labor to quickly develop installation standards for North America to reduce incidents of performance failures due to incorrect methods or materials.

Most recommendations right now are for installation on concrete – when considering thin tile installation on wood frame construction even more variables arise. “The TCNA lab has developed a massive research program to evaluate thin tile installation and minimum physical properties,” Astrachan said. “We are trying to get that funded and hope to have more definitive guidance sometime next year.”

Here are some of the important factors Astrachan said must be considered in thin-tile installation:

• Lippage must be virtually non-existent to avoid chipping damage to the thin edge.
• Coverage must be 100% at the edges to prevent edge cracking.

Generally people say coverage should be 100% everywhere but we have seen successful installations with less than 100% coverage – however, performance will depend greatly on the thickness of the tile and type of reinforcement.

The amount of extra tile needed for a job can be much more than a regular project if the pieces being installed are large. It is easy to break a piece and then another large piece (several square feet) would be needed.

Astrachan said that in general, reinforced thin tiles are being installed on floors in new construction as well as in renovations over existing tile. “One of the popular wall tile applications is to go over existing tile in showers to create a very clean and uninterrupted appearance,” he said.

The NTCA Technical Committee has addressed thin tile in its 2010 NTCA Reference Manual on page E4 “Tile Not Manufactured to Industry Standards.” It’s also being discussed at the upcoming meeting this month during Total Solutions Plus in a committee headed by TCNA’s Bill Griese.

In the field
Artcraft Granite, Marble & Tile’s James Woelfel has installed Kerlite 3 mm, 16″x40″ thin tiles in about 10 new construction projects of about 100-200 square feet each. Woelfel said the material was very easy to handle, but the reinforced backing created cracking problems when scoring with a glass cutter, so the Mesa, Arizona-based, NTCA Five-Star contractor used a wet saw instead. There were also tile waste problems when the scored tile cracked, and when at least one box of crushed or broken tiles came in each shipment.

Woelfel had good success with MAPEI’s Kerabond/Keralastic mortar system, which was recommended by the manufacturer. MAPEI’s Granirapid can also be used for vertical large thin tile installations, as well as MAPEI Ultralite, a high-performance, deformable, one-part cement adhesive with zero vertical slip and longer open time.

“MAPEI recommends a trowel with slanted teeth to allow the mortar to lay down more easily without sliding the tile to comb over the trowel ridges,” Astrachan said. “Unlike traditional tiles, it is very difficult to slide large thin pieces.” In addition, LATICRETE® 255 MultiMax® thin/medium bed mortar, 4-XLT® non-sag mortar, and Sure Set® medium-bed mortar can be used for thin tile installations.

For setting floor tiles, Astrachan observed a practice which goes against the grain of traditional tile installation: walking on the tile to embed it into the mortar. “This tile is flexible…stepping on it pushes it into place.” Not so much for beating the tile into the mortar with a rubber hammer, which can lead to breakage.

Astrachan stressed the importance of leveling the floor first, since mortar can’t be used to build up irregularities in the subfloor beneath – and Woelfel cautioned contractors to fully level the substrate and ensure flatness. “It’s like setting vinyl tile on walls,” Woelfel said. “It will telescope anything beneath it.” Woefel recommended the tile contractor conduct taping of drywall; in some cases, the wall may need to be mudded for a flat surface.

Following are some new thin-tile products:

Cotto d’Este: Black-White, from the Kerlite collection, is manufactured to a slim 3mm thickness using the Lamina process. Sleek and contemporary, Black-White comes in 3×1 meter and 1×1 meter in black and white. Eco-friendly manufacturing is earmarked by reduced emissions and 25% natural gas consumption, plus recycled materials for packaging. Large porcelain stoneware slabs above 3.5 mm thick are reinforced with fiberglass mesh. www.cottodeste.it.

Fondovalle: Bi+Fusion technology used in Light 4 Fusion allows the production of large, lightweight, double-pressed 4.8 mm thick slabs with multiple loading and colored pastes, offering great technical performance.  www.fondovalle.it.

Gardenia Orchidea: Crete di Pian-della Fornace is the latest innovation from the Crystal Ker brand, which uses traditional press technology in a new way to produce extra fine, extremely thin, very white porcelain stoneware in 2.5 mm thickness for the wall covering and 4.5 mm for flooring. www.gardeniaorchidea.com.

Laminam: Linfa ceramic slab features Lamina technology to produce a 3 meter-long, 3 mm-thick tile with surface effects that imitate various types of wood such as cotton, hemp, bark and coconut. Linfa is made with up to 48% recycled content. www.laminam.it/eng.

Lea Ceramiche: Slimtech Re-Evolution 3mm porcelain now comes in sizes as large as 40″x118″, in a new resin-like texture created by Lamina technology. www.ceramichelea.it.

Panaria: The Doghe 0.3 collection is part of the new ZER0.3 line, which uses Lamina stoneware technology to produce large, thin, lightweight ceramic slabs. Doghe 0.3 offers a wood effect in three modern colors in 3mm-thick planks. www.panaria.it

Refin: Skin is the brand-new, 4.8 mm slim porcelain stoneware. Using dust-pressed technology, Skin offers the same technical and resistance features of standard thickness porcelain stoneware tiles, with added benefits offered by thin tile. www.refin-ceramic-tiles.com.

By David M. Gobis, CTC CSI
Ceramic Tile Consultant

Let me preface this article by saying I spent most of my working life on my knees like many of you. In the second phase of my career at the Ceramic Tile Education Foundation (CTEF), constant exposure to the Tile Council of North America (TCNA) Performance Testing Lab played a huge role in developing a greater understanding or in some cases confirmation of all those curious little nuances about tile and setting materials that we think we know but are really just guessing about. Now that my knees don’t work so well anymore (I wouldn’t have changed a thing) – and armed with new learning over a ten-year span at CTEF – I have entered the twilight segment of my career; inspection and consulting.

During the course of conversation with a bunch of contractors at an industry event, the question was asked, “What kind of failures do you see most often, relatively speaking?” The answer and subject of this article is decks, patios, and balconies. Some of my Southern friends say these applications will not survive a freeze/thaw environment, which I take exception to. My home is in Wisconsin where we have had frost warnings in the middle of June. Yet many exterior tile installations in commercial and public buildings around Wisconsin are still performing, some after over 100 years of service. I have installed slate, limestone, quarry tile, mosaics, and yes, porcelain and they are all doing just fine.

Beyond porcelain

Something I hear consistently is that only porcelain tile may be used on exterior applications. While in most instances porcelain is an excellent choice, many tiles have been used in exterior applications long before the popularity of porcelain tile. The industry-accepted recommendation for exterior environments is that tile with a porosity of greater than 5% should never be used in an exterior application, 3% or less is preferred.

This would include most quarry tile, many mosaic tiles and numerous other popular floor tiles besides porcelain. The more moisture and temperature cycle changes the tile is exposed to, the more appropriate one with lower porosity becomes; the less rainfall and temperature variation, the less the concern. While many stones can be used successfully in exterior applications you must be very careful to select the appropriate product for the geographic location. Stone products within their own generic family can perform quite differently depending on where quarried. A word to the wise: do not assume anything when it comes to stone applications. Tests for moisture absorption, freeze/thaw resistance, and slip resistance are available for stone as well as tile products.

Drainage is in the details

Incomplete waterproofing (that does not involve a system approach with flashing and pretreatment of cracks and corners) or lack of proper drainage and likely both is where things usually go bad from my experience. Exterior applications such as a slab on-grade patio do not automatically require waterproofing. The most important aspect of that type of installation is proper drainage. We know we should pre-pitch a shower-pan liner below the mortar bed for drainage, and the importance of proper slope for surface-applied waterproofing products. Decks and patios are no different. Whether the water is shed at the surface or below it, proper drainage is critical to avoiding damage from freeze/thaw, moisture expansion, and to limit efflorescence. The standard ” per foot or 2% slope is really a minimum that should be considered for any exterior application exposed to the elements. When using exterior wire-reinforced mortar beds, a drainage mat will aid the reduction of moisture retention dramatically. If tile is to be installed over an occupied space or the structure must be protected for other reasons, waterproofing AND drainage may be necessary.

Many setting-material manufacturers tend to be a little gun shy about their waterproofing products used in exterior applications. Claims history provides many good reasons for their aversion. Patios, decks, and balconies – particularly over living spaces – are not the place to experiment with your personally-engineered hybrid waterproofing system or strategy. My recommendation is to thoroughly research the system you are considering or the person specifying has selected. Make no assumptions! Unless it comes with written instructions for the specific application and a warranty, move on to another system.

Once selected, it should go without saying that ALL the instructions including flashing requirements need to be followed. Under most building codes, a flood test – while prudent – is not required for enclosed exterior decks such as balconies. A move is afoot, which I support, to require flood testing of horizontal-enclosed waterproof installations. There is a testing procedure under ASTM D-5957 that, while cumbersome in its current format, would work for tile installations.

Mortar considerations

The selection of setting materials and grout for exterior applications is not as simple as it may seem. It’s obvious that the thin-set mortar should be rated for a wet application. However not so obvious is the definition of wet application. A vertically-tiled surface is a very different wet application compared to a horizontal surface when it comes to waterproofing and thinset. Submersion (floor application in an exterior wet area) is a very specific performance requirement. Not all polymer-modified thinsets are suitable for submersion. A few contain polymers that will re-emulsify and others only when exposed to moisture for prolonged periods, like a floor in the wet season. All polymer or latex modified thinsets should be protected from exposure to the elements until they reach initial cure. This includes not only rain but direct exposure to sunlight. Premature exposure to rain will impact the performance of any thin-set and possibly render a latex or polymer thinset useless. On the other hand, heat causes rapid cement hydration that will greatly reduce the bonding abilities of the thinset.

The last caution and number one cause of all installation failures is lack of movement accommodation which is another article all by itself. One thing is certain. People love tile decks, patios, and balconies. However, those types of projects require a very exacting installation process where no short cuts are acceptable without having a negative effect on the tile installation. Exterior applications of ceramic tile require experienced tile installers using quality products. Many otherwise-good installers and some materials are simply not up to the task. Proper product selection and application are going to require more information than you will receive from your typical sales representative. Study all system components thoroughly and choose wisely before you venture outdoors.

David M. Gobis, a third-generation tile setter, is an independent technical consultant. He has been in the trade for over 35 years and owned a successful contracting business for many years prior to his current position. Gobis is an author of over 150 trade-related articles and a frequent speaker at industry events. He is a member of the Construction Specification Institute, International Code Council, American Concrete Institute, National Tile Contractors Technical Committee, voting member of The American National Standards for Ceramic Tile Installation and Setting Materials (ANSI A108/118), American Society for Testing of Materials (ASTM) C-21 Ceramic Whitewares, and Tile Council of America Installation Handbook committees. You can reach him via email, dave@ceramictileconsultant.com.

Schluter’s Systems’ new regional distribution center in Reno, Nevada demonstrates innovative uses of ceramic tile to support energy efficiency, comfort and utility

By Sean Gerolimatos, technical services manager, Schlüter Systems L.P.

Schluter Systems’ North American subsidiary was founded in 1986, with US and Canadian offices located in Plattsburgh, N.Y. and Montreal, Québec, respectively. To improve service to customers in the western United States and Canada, Schlüter Systems began construction of a regional distribution center (RDC) in Reno, Nevada in February 2011. Like previous construction projects, Schlüter Systems placed a strong emphasis on energy efficiency, comfort and utility, enabled in large part through the extensive use of ceramic tile.

Radiant-heated floors
Similar to the U.S. and Canadian headquarters [TileLetter, September 2010], a hydronic system of radiant heated and radiant-cooled floors and geothermal heat pumps both warm and cool the RDC offices and training center.

Geothermal heat pumps transfer energy to and from the earth and the building via the water in the hydronic system, turning the earth into a heat source during winter and a heat sink during summer. Because the temperature of the earth is warmer than the outside air in the winter and cooler than the outside air in the summer, this is an ultra-efficient process. RDC office floors incorporate a modular screed system and ceramic tile covering, which combine to reduce the water temperatures necessary to heat the building and in turn maximize efficiency of the heat pumps.

Radiant-heated walls
The warehouse plans initially called for combustion heaters, but these plans changed after a conversation between Schlüter Systems North America president Reinhard Plank and company founder Werner Schlüter. The European Union has placed increased focus on public and private building renovations as part of a 2007 initiative to achieve 20% savings in energy use by 2020. Based on its experience with geothermal hydronic radiant-heated floors, Schlüter Systems Germany has been investigating radiant-heated walls. Mr. Schlüter suggested a system in the RDC warehouse to gain practical experience with this process in renovations.

The foundation for this radiant-heated wall is an extruded polystyrene-foam tile backer board/building panel, with an overall 3″ foam thickness to provide sufficient insulation (total R-Value of approximately 8.0), achieved by using two layers of the foam board.

First, a layer of 1″ thick board was spot-bonded to the existing masonry walls using dabs of mortar, which allowed the installers to ensure flat, plumb and square surfaces for setting tile. Next, a layer of 2″-thick board, with grooves spaced at 6″ on-center to hold the hydronic tubes was installed with the grooves facing out, using thinset mortar in a full-spread application. The grooves were produced using a plywood template and a common router with 3/4″ U-shaped bit and vacuum attachment. All 400 of the 24-1/2″x96″ boards were prepared in three days with virtually no mess or complications.

Once the two layers of foam boards were installed, the plumber inserted the hydronic tubing and performed a pressure test to check for leaks. After the successful tubing test, the tile setters applied the tile covering using the thinbed method. Tile edges were finished using a rounded profile at the top and ends of the walls, and a cove-shaped profile at the floor-to-wall transition. The result was a lightweight, easy-to install wall system that offers improved insulation and heating efficiency.

In total, the 8′-high walls span 775′, covering an area of 6,200 square feet.

The walls are expected to support approximately 50% of the heating load in the warehouse with the other 50% coming from a solar wall and supplemental heaters if required.

In addition, since the overall capacity of the geothermal system (and therefore the number of wells) was determined by the summer cooling load, the radiant walls will use heat that would otherwise have been stored in a water tower to balance the system. Thus, the “excess” energy will be put to practical use and improve the comfort of the warehouse personnel during the winter. For example, incorporating a radiant-heating system will minimize the heat loss caused by opening bay doors to load and unload trucks.

Lavatory countertops and sinks
Given their design flexibility and hygienic properties, ceramic tiles represent the ideal covering material for lavatory countertops.

As a veneer, tile needs a dimensionally stable surface for installation – one that is flat, level, plumb and square. Typical building materials often do not fit the bill, even with underlayments and membranes.

In the RDC, lavatory countertops and sinks are constructed entirely from the same foam boards used in the radiant-heated walls described above. Vertical supports were formed by laminating two layers of 2″-thick panels and adhering them to the floor. The decks consist of single 2″-thick panels with additional reinforcement coming from stainless steel U-profiles at front and back. Next, 5″-wide sections of 2″-thick board were adhered to the decks adjacent to the back walls to provide a flat surface above the sink basins for mounting the faucets.

Sink basins were formed in three steps. First, 1-1/2″-tall sections of board were adhered to the perimeters of the decks. Next, the undersides of 1/2″-thick boards were scored with diagonal relief cuts through the facers. The boards were attached to the perimeter supports and bent along the relief cuts to slope toward the faucet supports. Finally, linear drains with integrated bonding flanges were set into the basins and connected to the waste lines.
Throughout the process of building the countertops and sink basins, the vertical surfaces were plumbed, the horizontal surfaces were made level, and all corners were made square, providing an ideal surface to set the tile and trim profiles and achieve a successful installation.

Conclusions
The unique applications of ceramic tile in Schlüter Systems’ regional distribution center in Reno, Nevada serve as examples of how ceramic tiles can function as more than just coverings; they can become integral components of overall building systems to provide improved energy efficiency, comfort and utility.

Sean Gerolimatos is the technical director for Schlüter Systems L.P. and has been with the company since 2003. He has served as a member of the TCNA Handbook Membrane Subcommittee, written articles for trade publications, and presented seminars at tile industry events, including Qualicer and Surfaces. His academic background is in civil engineering, earning a Bachelor of Science from Clarkson University and a Master of Science from Cornell University.

You’ve got the job or the contract – now it’s time to determine the pattern.
Installing ceramic/porcelain tile or stone tile in a pleasing, attractive pattern is as critical to the project as the color, size or texture of tile with which you’re working. The pattern needs to compliment the dimensions of the room and the overall setting without overwhelming the demands of the space.
In this story, we’ll talk to two prominent contractors about the intricacies involved in determining and setting patterns: Elizabeth and Dan Lambert of Lambert Tile & Stone from Eagle Colorado and Andre Hutchinson, of Dillon Stone Corp., Virginia Beach, Va.
[Read more...]