Ceramic tile remains one of the most desirable types of flooring but, as any installer can tell you, it requires a certain level of expertise to make certain it looks great and performs as expected. The ability to detect, troubleshoot and—most important—solve problems is a major asset for any installer. So let’s look at the issues that most frequently surface with ceramic tile in a residential setting. We’ll break up the discussion into the areas most commonly affected: the bonding of the ceramic tile and issues surrounding the grout.

Bonding Issues: Cement backer board

A common problem for homeowners is the loss of bond or the cracking of the tile. As an example, let’s look at tile with cement backer board underlayment installed over wood frame construct floors. Before starting work, the installer needs to know specifics about the board product used under the ceramic tile. Too often, the cement backer board is not properly bedded using the required thin set mortar. (This is needed to establish the supporting plane of the cement backer unit. See Tile Council of North America (TCNA) detail F144-07 for more details.)

If installed improperly, the backer board can cause the grout joints and tiles to crack and potentially lose their bond. Generally speaking, board manufacturers require that their board products be bedded in a layer of ANSI A118.1 or ANSI A118.4 compliant thin set mortar. In many cases, the entire ceramic tile installation may have to be uprooted to correct this problem. If the problem is isolated, a spot repair can be attempted by using a highly flexible latex fortified thin set mortar to replace the tiles.  Even so, there would be no guarantee that the problem will not arise again somewhere else in the installation.

Another common problem is the lack of (manufacturer required) cement backer board seam treatment. This is another required step that can prevent the grout and tile from cracking. Generally, a minimum 2” (50mm) wide alkali resistant fiber mesh tape is embedded and coated with a layer of latex fortified Portland cement thin set mortar . Other important steps involve the use of corrosion resistant fasteners and following the correct fastening pattern provided by the board manufacturer. This also means the correct layout of the boards, the correct total subfloor configuration, the correct spacing of board seams and the use of the correct thin set adhesive mortar for the bonding of the tiles.

If problems arise with a cement backer unit, a spot repair on an isolated area may be in order. On the other hand, if a project is experiencing widespread problems, an entire replacement may be called for.

Expansion Joints

How much is enough?  Using the proper amount of adhesive is essential. For interior jobs, you need to achieve a minimum of 80% continuous thin set mortar coverage or you'll risk  cracked tile and ultimately loss of bond.

Remember, all ceramic tile installations will experience movement. As such, a big issue involves expansion joints—or more specifically, the lack thereof. Expansion joints provide relief and an avenue for free movement in ceramic tile installations. They are critical to a long-lasting and functional ceramic tile assembly.

It is becoming even more of a concern as ceramic tile installations become more technical. Increasingly, we are seeing components that require even greater movement allowance to accommodate floor warming systems, waterproofing membranes, sound control underlayments and crack isolation membranes. As a rule of thumb, interior movement joints should be placed every 20’ to 25’ (6 to 7.5 m) in each direction, at all perimeter joints and all joints that meet a staircase, columns, baseboards, pipes, radiators or other restraining element. Failure to use expansion joints properly can result in floors actually heaving from the substrate.

If a problem related to an expansion joint appears, it may be possible to carefully cut the grout joints (or even the tiles) to provide relief for the ceramic tile assembly. Although not optimal, it may be enough to salvage an installation.

Thin Set Mortar Coverage

Another major concern involves assuring the tiles are completely bedded using the appropriate adhesive mortar. The first rule: make sure you use enough. Industry standards require that the finish materials achieve a minimum of 80% continuous thin set mortar coverage for interior applications (it’s 95% for exteriors and interior wet areas). Inadequate coverage can lead to cracked tile and grout and loss of bond to the tiles.

During the installation, it’s a good idea to periodically pick up a tile to assure that proper coverage is being achieved. Use the appropriate sized notch trowel and tap or twist the tiles in place to assure they are properly bedded. Large format tiles can be back buttered with additional thin set mortar to ensure that the appropriate coverage is achieved.

To correct these errors, carefully remove the grout around the perimeter of the loose tiles and any hardened thin set mortar so as to not disturb any tiles that are still well bonded and then replace using the appropriate troweling technique.

Other Bonding Problems

Another point to consider is selection of the appropriate setting material. Is it the right type for the substrate? Is it appropriate for the application that is receiving the ceramic tile? More importantly, can the substrate even support ceramic tile? If this is an area that previously had carpeting or vinyl, it’s a good bet the structure is not robust enough to handle the much heavier ceramic tile installation. If it is up to the task, make sure the substrate is clean (that means free of all bonding breaking and such potentially bond inhibiting materials as paint, dirt, oils, grease and old adhesives).

Grout issues: Cracking

Grout cracking stems from the problems associated mentioned above. But there may be isolated areas that are cracking due to poor installation techniques; including improper packing of the grout joints or lack of protection while the grout was fresh. If it is just the grout cracking (and not the tile) carefully remove the affected areas and re-grout the area in accord with the grout manufacturer’s instructions. The newly patched areas may not completely match the existing grout. Even when the same control numbers are used, issues like age, mixing technique, temperature humidity and other site conditions can cause shading issues.

Staining / Discoloration /Powdering

Perhaps the most frustrating issue for homeowners is the care and upkeep of their grout. Not all grouts resist all stains, dirt or anything else that can be thrown at the ceramic tile installation.

Portland cement based grouts, for example, will stain and discolor over time. They can even powder out. Lighter colors (regardless of whether they are sealed or not) will show more wear and tear than darker colors. The area of use or the project conditions will also have a direct bearing on how the tile and grout wears.

Cement based grout should be sealed to help prevent discoloration and staining. Grout sealers are available in many forms and generally need to be reapplied every six to 12 months. (Consult a reputable sealer manufacturer for more information on the appropriate sealer type and frequency of application for your specific application.)

A new generation epoxy based grout can alleviate many of the common problems associated with cement based grouts. These grouts tend to be denser. That means a lower absorption rate, which makes the grout resistant to stains penetrating into the grout. Often, a potential stain just sits on the surface and can be easily cleaned with a neutral pH cleaner and scrub pad.

These epoxy grouts can even be installed in existing ceramic tile installations. As you carefully remove the existing grout, leave at least half the depth of the grout joint open to receive the new grout. Use a grout joint removal tool you are comfortable with (they range from handheld grout rakes to dustless electric powered grout saws) and take care to prevent the tile edges from chipping and from flying debris and dust. Eye protection is a must. Once the existing grout is removed, the new grout can be installed in accordance with the grout manufacturer’s installation instructions.

Although the epoxy grouts are a huge improvement over traditional cement based grouts, they are not self-cleaning. A neutral pH cleaner is usually all that is required to clean the floor followed by a good rinsing. For stubborn areas, a bleaching type cleanser (e.g. Soft Scrub with Bleach) and a scrub pad can be used from time to time. Always follow the cleaning process with a good rinse of cool clean water.

Maintenance

Ceramic tile installations are probably the easiest flooring type to maintain. A periodic wash with a suitable cleaner is all that is required. In addition, ceramic tile is one of the healthiest flooring finishes. There is no off-gassing or volatile organic compounds emitted into the air. In addition, ceramic tile floors have a long lifecycle when compared to carpeting and resilient floors. That means that the upfront investment for ceramic tile will wind up costing less over the years. Now that’s low maintenance!

Ceramic tile installations add value to any home and provide a beautiful yet functional finish that enhances any décor. Correctly installing and troubleshooting ceramic tile installations can lead to years of low maintenance service and very satisfied consumers. - Arthur Mintie, CSI, CDT. Director of Technical Services, LATICRETE International, Inc.