CSI: Tile When Installations Fail
 
March 1st, 2007

By Jeffrey Steele

March-April 2007

Talk to experts who regularly investigate tile failure, and they will tick off a lengthy laundry list of causes. Inadequate substrate preparation, inadequate or improper setting materials, failure to take into account movement of floors and walls, premature traffic on tile installations, problems with curing compounds, excessive deflection and installer ignorance or arrogance are among causes cited.

In some cases, most or all of these factors can play into a perfect storm of tile failure. In the pages to follow, we will examine the problems that plague both residential and commercial tile applications, the ways they cause or contribute to tile failure and the best ways to combat these issues.

Inadequate Substrate Preparation

At San Diego-based Ceramic Tile and Stone Consultants, founder Donato Pompo and his staff members serve as consultants to the ceramic tile and stone industry, conducting ceramic tile and natural stone forensic investigations in cases where tile has failed. If tiles have become loose or are damaged, Pompo will launch an investigation of conditions leading to the failure and will recommend a remediation.

He frequently finds cases of tenting or buckling of tile, in which an entire section of tile raises off the substrate, or of cracking within tiles.

“That’s because the substrate was inadequately prepared,” he says. “We get a lot of calls on this lippage issue, where the tile isn’t installed correctly, and isn’t installed evenly, and it causes one edge of the tile to be higher than the other.”

But that isn’t the only example of inadequate substrate preparation. Another occurs when installers attempt to bond tile directly to a concrete slab, Pompo says.

The problem? Concrete slabs are never totally flat, but have high and low spots. To overcome this issue, the low spots should be filled in, and the high spots ground down, before any attempt is made to set the tile, he says.

Inadequate/Improper Setting Materials

According to Dave Gobis, Clemson, SC-based executive director of the Ceramic Tile Education Foundation (CTEF), lack of thin set coverage under the tile is one of the biggest causes of failure.

“The industry standard is 80 percent interior, 95 percent exterior and in wet areas,” he says. “If the tile doesn’t get the support it needs, if you don’t have the tile firmly bedded, it’s not going to take much time to work that tile off the floor . . . The type of thin set that’s used overcomes problems. It will help compensate for not having enough thin set on in the first place. Thin set can definitely compensate for a lot of things, but you still need to get enough thin set.”

Inadequate Movement Joints

Several experts cite improper utilization of movement joints as a primary source of tile failure. Among them is Noah Chitty, technical services director of StonePeak Ceramics, with headquarters in Chicago and a factory in Crossville, Tennessee.

“All tile expands and contracts,” he remarks. “And even though it expands and contracts less than other covering materials, there still needs to be adequate compensation for the movement of the building and floor itself.”

A classic example is the grout at the 90-degree angle between bathtub and wall. If hard grout rather than a flexible material is used, the weight of the water and the individual in the tub—or the natural movement of the house itself—can crack that joint, allowing a pathway for water to enter into the wall cavity, Chitty says.

Gobis agrees lack of movement joints is a chief culprit. “Walls move, floors move and everyone’s always quick to blame something,” he says. “But if there’s no accommodation for movement in the installation, it’s a problem.

“Every single building material moves, and they all move at different rates. I’ve had tile failure through lack of movement accommodation from two years to 56 years [after a home’s construction]…It’s not tile product failure. It’s a failure of the installer to provide for movement.”

A lack of movement joints is also one of the causes of loose or unbonded tile, Gobis adds. “But you have to be ultratechnical to make that call,” he notes.

Premature Traffic on Fresh Installations

Gobis cautions that when installing porcelain tile, installers must allow extra time for the thin set to dry. That’s because porcelain is impervious, and doesn’t allow moisture to evaporate or be absorbed. “Think of Elmer’s Glue between two sheets of glass; it will never dry,” he says. “You can overcome that, but you need to pay for it. Some thin sets are designed for more rapid drying cycles. Premature traffic then causes tile failure because the tile comes loose. It dries like a picture frame.”

Excessive deflection

Too much bounce in a floor can prove another fatal problem for tile installations, Gobis says. Houses are designed for average weight, but tile weighs a lot more, he notes. “Often you end up with seven to nine pounds per square foot of dead weight. So structures need to be designed to compensate for the weight of the tile. The real issue is not with the floor joists, but with the area in between the joists.”

If it’s a high-traffic area, for instance one in which a lot of deliveries are received, the application calls for a superior thin set. “And up on the second floor, it better be even more superior,” Gobis says. “Take the deliveries and traffic, and add some bounce. It’s accelerated by the fact it’s on the second floor. So there’s no such thing as one thin set that’s good for everything.”

Curing Compounds

Curing compounds, which seal moisture into concrete, are used with virtually every concrete slab, Gobis reports. That’s fine, but the same compound that prevents moisture from coming out of the concrete also prevents thin set from binding. “If all the holes are full of curing compound, there’s not going to be any bond,” he says.

“You can use a good latex and polymer—premium thin sets—and it will help but not overcome the problem of curing compounds. Any industry observer would say the curing compound must be removed.”

Leaky Showers

Gobis feels 85 percent of the showers built today are not properly constructed, and he bases that assessment on some 35 years of observation.

The biggest cause of mold in showers is lack of prepitch, a membrane pitched to the drain. And this is not a new problem, he observes, adding he has taken apart showers that are 100 years old and discovered the same flaw.

“If you have a leak in a shower stall, the leak rots the structure supporting the tile,” he says. “Rotten leaky showers. Nasty, nasty.”

Pompo is in full agreement that moisture intrusion around showers is a huge factor in tile failure. Though many people cite mold as a failure mechanism, mold is only a symptom of the failure mechanism, he says, noting it’s impossible to have mold without having moisture. “Water intrusion is a very expensive failure in our industry, and the construction industry at large,” he says. “That’s why, particularly in showers, it’s important that shower applications are properly waterproofed. If it’s installed incorrectly, water can migrate into the wall cavities, leading to mold and other water damage.”

Chain Reactions

In most cases of tile failure, no one factor is to blame, Pompo asserts. Instead, the failure is the result of compounding issues. A typical scenario is that the installer didn’t properly prepare the substrate, allowing a contaminant to interfere with the bond or the attachment of the thin set.

The installer may also not have applied enough thin set to achieve the minimum requirement of 80 to 95 percent contact, and may not have included expansion joints to restrain the tile from moving. “And they may have had a moisture problem, with excessive moisture in the slab, or too much deflection in the substrate,” Pompo adds.

Stone Tile Failures

Over the last several years, there has been a much greater incidence of stone tile failure, in part because stone is being used far more frequently than in the past, Pompo reports. In some cases, the failures of stone installations are similar to those found in ceramic tile, but there are significant differences as well.

“Stone is much more sensitive to moisture than ceramic tile, and that can lead to efflorescence issues, where you get the whitish salt from underneath, with water the transporter,” he says. “Water can pass through more easily in some stones. We also see a lot more lippage problems with stone, generally because they’re being installed with narrower grout joints over substrates that have not been properly prepared.”

Essentially, stone is a much more moisture-sensitive product than clay ceramic tile, Pompo adds. Some stone will expand with moisture, leading to warpage. In addition, installers are using thin set that is much thicker than customary, and thicker than what manufacturers recommend. That adds additional moisture that leads to excessive shrinkage within the thin set.

“When this is done over an elastomeric membrane, the membrane is not able to restrain the tile from moving, as it would if it was bonded directly to the concrete,” he notes. “This leads to indent fracturing, where the stone is actually compressed from the excessive shrinkage in the thin set, causing spider web indents in the face of the stone. You can’t fill them, but you can see them at different angles as the light reflects off them. Eventually they may lead to cracking.

“Along with this excessive thin set, it may lead the crack isolation membrane to release from the concrete, because the membrane isn’t designed to control vertical movement. This has been a big deal over the last several years, and as a result we’re seeing a lot of failures.”

Installer Error and Arrogance

As the above suggests, the problem often lies not with the product itself but with simple inability or unwillingness on the part of the installer to perform the job correctly.

Pompo likes to cite figures that help explain the high rate of installer errors. According to the Tile Council of North America, the tile industry had seen sales double to 2.274 billion square feet over the seven years leading up to 2001, he reports. Yet in that seven-year period, the number of people identified as tile setters increased by only 25 percent, based on U.S. Department of Commerce figures.

“We’ve grown so rapidly that our force of skilled installers has not kept pace,” Pompo says. “Because they need the manpower to perform the work, there are a lot of installers working who don’t fully understand the complexity of the work they’re doing.

“We as an industry have a limited amount of training involved for installers. There are no trade schools or colleges for installers to learn the proper methods and industry standards. Most of these installers learn on the job. So they don’t have the formal education, and are just being told by someone else what to do. . .Even though they have good intentions, we find there are many mistakes done during installation.”

Putting the issue considerably more bluntly is Tim Bolby, director of technical services with Crossville Tile in Crossville, Tenn. “In both residential and commercial [applications], there is what I would call ignorance to the point of arrogance,” says Bolby, who started in the installation segment of the trade, before moving to the setting materials industry and eventually to Crossville Tile, where he helps intervene in disputes regarding product complaints.

“It could involve a carpet installer new to the craft of setting tile, but just because he’s had a trowel in his hand thinks he can do it. There are those who will take on jobs and use them as learning experiences. Consider the advent of new mortars, and the advent of glass or metallized tiles. They all have unique qualities that require continuing education on the part of the contracting and installation sector. And they just don’t do it.

“Basic education is in short supply, not to mention specialized education. I have to tell you there is an awful lot of ignorance out there [with] this continued belief that because they have set ceramic tile, they know all about tile. That’s just not the case.”

He adds that Crossville Tile regularly stages training seminars, and the installers who most need the training are among the least likely to attend. Meanwhile, the skilled installers who take pride in their craft are invariably in the audience.

“There are those who want to be as good as they can be, and they take time out of their private lives to get the information,” Bolby says. ”The ones who don’t want the information and don’t care, they go sometimes, but they’re just there for the 12-pack.”

But education and training are the keys to eliminating installer errors, says Chitty. “Education of manufacturers, distributors, end users and contractors is crucial to the long-term success of our industry,” he says.

“And that education can be provided through our industry associations and educational partners like the TCNA [Tile Council of North America], the NTCA [National Tile Contractors Association] and the CTEF [Ceramic Tile Education Foundation], as well as various other groups. All of us who participate on committees and in the technical realm all feel participation of the industry is vital.”

In its quality control efforts, Ceramic Tile and Stone Consultants takes on a training role, teaching installers how to install correctly and helping them understand industry standards. “After they learn, it becomes habit for them to do it the right way,” Pompo says. “I commonly say there’s never been a failure we investigated that met industry standards and in spite of that failed. The failures always indicate that industry standards were not followed. If the installers had followed the industry standards, they could avoid failures.”

SOURCES:

Tim Bolby

Director of Technical Services

Crossville Tile

Crossville, TN

931-484-2110

Noah Chitty

Technical Services Director

StonePeak Ceramics

Crossville, TN

931-459-2518

Dave Gobis

Executive Director

Ceramic Tile Education Foundation

Clemson, SC

864-222-2131

Donato Pompo

Founder

Ceramic Tile and Stone Consultants

San Diego, CA

619-669-2967

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