Repairing a Tile Floor
Repairs are a part of almost every floor’s life. In the case of some floors, maintaining historical value may be the reason for repairs, while other, less noble repairs have to be made because of a problem or deficiency with the installation. Ceramic tiles, when properly specified and installed can easily outlast any building in which they are installed. This makes ceramic tile the most economical of all available floor covering materials. Nevertheless some repairs to the tile, grout, adhesive layer, or setting bed are inevitable. The most important aspect of any repair is to assess the damage and likelihood of a successful repair. Finding suitable replacement tiles is the next task, followed by preparation, installation, and finishing.
Assessing the RepairHistoric or practical, the first signs of the need for repair usually appear in the grout joints with cracks or deteriorating grout. The next sign is either cracked or loose tiles. Reading the visible symptoms is critical to developing a reasonable repair strategy: is the floor really worth the effort to repair, or should it be torn out completely?
First, determine the age of the floor and compare this to the number of problem areas: An old floor with a half-dozen small gaps in the grout, and no visibly damaged tiles can probably be safely and easily repaired, while a new floor, with the same grout problem, may be indicating a fundamental flaw within the installation (no thin-set mortar beneath the floor’s backer boards, for example) for which no repairs to the grout will cure. It is best not to jump to snap decisions, but to examine closely.
Generally, if there is a structural problem with the installation, symptoms of grout or tile problems will usually appear within the first few years of the installation’s life. This also applies to installations where no movement joints have been incorporated into the original installation, and normal building movement begins opening up cracks and shearing tiles off the setting bed. Other factors that can cause poor grout and cracked or loose tiles to appear early on are the quality of the grout, the quality and percentage of contact of the tile adhesive, and the quality of the setting bed.
The lack of movement joints is a major cause of tile installation failure. If tiles are shearing off around movement joint areas (see TCNA Handbook, EJ171), a good repair is only possible if all grout and adhesive mortars are removed and replaced with a resilient material, along with the tile-replacement work.
To remove large amounts of grout, I recommend the use of a reciprocating grout removal tool. The Internet has links to several saws and power grout removal tools made in the U.S. and abroad. For removing small amounts of grout from joints at least 1/8-inch wide, I use a backer board scoring tool (the design-specific hand tools I have used for this purpose have been greatly over-rated, in my opinion).
Porous grout is absorbent and prone to staining, erosion, powdering, and crumbling: If the problem is confined to the grout only, spot repairs are not recommended because the remaining original grout will continue to fail. Instead, all old grout should be removed; the joints cleaned of all soap and wax residues, and repacked with latex grout matched to the original.
Grout should be extremely hard and tough. When properly cured, it should resist and quickly dull any knife used in an attempt to remove it, yet many grout joints are filled with soft grout due to over-watering during mixing or initial cleaning. If grout is soft enough to gouge out with your thumbnail, it is not worth repairing.
One loose tile that has parted from the setting bed can reveal much about the quality of the installation: trowel marks visible in the adhesive layer can indicate less than 50% adhesive coverage, and a lack of anticipated compressive and bond strengths. Tile adhesive plays a critical role in the life span of a tile installation. When coverage is 90% or higher, the installation has a chance of achieving long life with the fewest broken or crack tiles and repairs, but when coverage is lower, longevity decreases, and cracked and loose tiles and repairs increase. This is especially true in wet-area installations.
Functional, wet-area installation repairs are complicated by the presence of either traditional or surface-installed waterproofing membrane systems. The shock of percussion tools, either hand or power actuated, is sufficient to damage most membrane (this applies to waterproofing, crack isolation, and sound attenuation) systems. When a membrane is involved, demolition should be done with diamond blade tools to reduce the risk of damage. For waterproofing, it is always best to subject repair areas to standard water testing whenever possible. If not, some provision should be made, in contract, to limit liability.
When to Repair, When to ReplaceIf inspection of the problem reveals only problems with the grout, and all other aspects of the installation are sound, I generally try to retain as much of the original installation as possible, and apply spot or full-replacement, as needed.
When repair problems involve cracked or broken tiles, and inspection reveals fundamental problems with the adhesive, the setting bed, integrity of the membrane system, or the impaired strength of the tiles or the structure, tile repairs are usually out of the question, and only complete replacement, built on the necessary repairs, makes good sense. If the repair problems are localized and not caused by any perceived short-comings of the installation, and comprise only a fraction of the installation-less than 10% cracked tiles, for example-I feel relatively safe specifying spot repairs. But damages above 10% may indicate a deeper problem that spot repair, only, will not fix. For these installations, I specify not only a replacement, but also an upgraded restoration that includes demolition, a serious structural mapping and analysis, and a carefully detailed installation with appropriate bolsters installed, wherever possible, at every layer of the rebuilding.
Finding Replacement TilesSometimes, the most difficult part of the repair process is to find a suitable replacement. Given the life expectancy of ceramic tile, it is not uncommon for the original manufacturer to be out of business, leaving scant stocks of tiles available for repairs. In past years, it was possible to select colors that had been used for upwards of 50 years or more, but today, only Dal-Tile still offers a handful of old favorites, and most import tiles, after five years or so, are virtually impossible to find. A Google search will turn up hundreds of links to manufacturers who carry many old made-in-the-USA brands, colors and trims, and there are national, regional, and local sources of old ceramic tiles.
I was amazed years ago when working on the restoration of tiles in the Old Executive Office Building in Washington, D.C. to find a British tile company that still had a copy of the original order placed in 1875, and had a full selection of the tiles needed to effect various repairs throughout the building! A search of the Internet can direct you to hundreds of sources of original and restoration copies of foreign-made tiles. The Tile Heritage Foundation (www.tileheritage.org) sells numerous reprints of old tile catalogs, and is a great source for identifying old tiles. A last resort for many historic or nostalgic repairs is the local potter or ceramic artist with a kiln and patience with tile bodies and glazes. This route may be expensive and time-consuming to get the tile body and glaze just right.
When close replacements are not available or within the budget, the most reasonable alternative is to use a tile whose color most closely matches the original, and whose actual size is large enough to be cut, to the required size, on a wet saw. Besides color and minimum size, thickness and edge treatment are crucial to a convincing repair. Thickness is less of a problem because adjustments can be made to the setting bed to account for variations in thickness, or, if the desired size is not too large (about one-third the diameter of the wet-saw blade), the tile body itself-if thick enough-can be sliced thin through careful edge-cutting work on the wet-saw. A check of most local tile suppliers should uncover a wide variety of colors and sizes suitable for reasonable replacements. No such adjustments can be made to change the edge treatment of a ceramic tile, but both wet and dry-cutting tools can be used to profile color-through, unglazed porcelain and most hard stone tiles to match original, manufactured profiles and shapes. The local stone fabricator is the obvious first choice for stone tile replacement or trim shape fabrication.
Replacement Installation Methods, Materials, and TechniquesOne of the most important parts of the preparations for repairs is the removal of all original grout surround the replacement tile, and all adhesive residues in the footprint of any tile being replaced. Without these two actions, it is highly unlikely you will coax the replacement tiles into the same level plane as the originals, or into an even alignment with its neighboring tiles. Removing grout is relatively simple as long as the joint width is 1/8-inch or wider. This allows the center of the grout joint to be evacuated by a dry-cutting diamond blade: the remaining grout practically falls away from the sides of the tiles with a flick of the blade of a utility knife.
Eliminating the grout surrounding any tile needing removal is one of the keys to limiting damage to surrounding, undamaged tiles: without solid grout, demolition shocks are absorbed into the setting bed, rather than jump from one tile to another. To remove any cracked or chipped tiles that are still firmly bonded to the setting bed, I slice through the target tile, at frequent intervals, with a dry-cutting blade set to just pierce the bottom of the tile (and avoid contact with any surface-applied membrane system components). I gently pry away at the kerfs, or use gentle, sideways blows against a small chisel, to remove waste material, and finish the job with knife blades or scrapers.
To lessen the impact on the setting bed, I use a variety of hand and air and electric power tools to remove the adhesive residues. Again, for small areas, I use a backerboard scoring tool to rough out the adhesive residues, and use knives and scrapers to remove the remaining traces. If there is enough room, I use a dry-cutting diamond cup wheel. On larger repairs, I scale up the tooling to suit the size of the repair and the strength of the setting bed, with on-grade concrete slabs able to handle the most impacts and demolition shocks. I tend to reserve percussion, impacting, and chipping tools for concrete repairs, and specify rotating or reciprocating devices for wood floor systems, or installations that incorporate a membrane system. Once the grout and adhesive residues have been removed, it is a good idea to clean off the sides of the tiles, to remove any soap or wax residues, with a neutral cleaner or degreaser prior to installation of the replacement tiles.
Flexibility and decreased absorbency are important properties for any grout, especially those used in repairs, but color matching is important, too. For best results when spot repairing grout, it is a good idea to thoroughly clean the remaining original grout, to help the old colors stand out as true as possible. When the replacement grout has dried and cured, it is highly recommended that the entire installation be sealed with a quality sealer or impregnator. I prefer to use Miracle 511 for this task.
During the rebuilding, it is important to allow all materials to cure fully and properly: premature covering-over can stall or permanently suspend curing of underlying materials. When using impervious tiles, membrane systems, and other installation materials, it is not uncommon for curing to last two or three times longer than normal. As always, refer to each manufacturer’s printed instructions for all the fine print.