(Photo 1): The author marks the edge of a tile for grinding to allow for a closer fit.


For thousands of years, ceramic tile has been one of the most colorful and durable of all finishing materials. There are virtually no limits to the shapes, colors, and designs of tile, and there are countless ways to install tile so that the installation will be easy to maintain. This article is not so much about installations as it is about dealing with art and decorative tiles. For tile installation guidelines and specifications, refer to the TCNA Handbook and the ANSI A108. For more information regarding the properties of ceramic tile, refer to ANSI A137.

(Photo 2) The author uses a dry-cutting diamond blade to square the shoulder of the tile.

Selecting tile and installation materials

For installations located in dry areas that are not functional (a purely decorative interior wall mosaic, for example), practically any material can, and has been, used as tiling material. For functional and exterior installations though, tile and material selection are critical and key to longevity and ease of maintenance. Some art and decorative tiles have a relatively soft glaze, which would not be appropriate for use on floors, countertops, or walls that receive frequent cleaning. In wet area installations, ceramic or stone tile bodies should be non-porous so they do not absorb moisture that can promote the growth of mold, or cause freeze/thaw damage. ANSI A137 specifications were developed for ceramic tiles, but the properties of absorption, break strength, and resistance to wear or staining, among others, can also apply to stone, cement, or other types of hard tiles. Make sure the tiles you select are up to the anticipated demands of the installation.

Regarding setting bed, adhesive, and grout materials, I have examined numerous art and decorative installations that failed because someone chose the wrong materials. When installing premium tiles, it really does pay to not scrimp on materials. For example, many porcelain or glass tile installations fail simply because a dry set thinset mortar or mastic was used instead of a latex or an epoxy thinset as specified by the tile manufacturer. Using a substandard adhesive, grout or other installation material is poor economy for the customer and the installer.

(Photo 3) This 60-year-old wet saw, designed for 4-1/4” and 6” tiles, is the author’s choice when side-cutting an intricate cut, like the outline of this inlayed tile.

Fabricating the tiles

Unlike commodity tiles that are machine-made (uniform and simple to stack or lay), many art and decorative tiles are irregularly shaped and sized, and require a bit more work for a good fit and finish. For example, to maintain a slender 1/8-inch joint between an inlayed section of sheet-mounted, hand-molded mosaic tiles and the surrounding hardwood floor, I had to identify the edges of the tiles at the perimeter of the inlay (Photo 1), and grind away a portion of the bisque (Photo 2), which, as part of the pressing process, is splayed and would otherwise make for a rather wide joint.

When inlaying irregularly shaped tiles into other tiles, I use a waterproof marker to indicate the desired cutting outline, and use the side of the wet saw blade to remove unwanted material (Photo 3).

(Photo 4) Four of the midnight granite tiles were cut to accept and outline the gold trim tiles. To cut for the long squiggle, the author side-cut the tiles on a wet saw; the cutouts for the gold dots were made with a small diameter diamond core bit (MK Diamond, www.mkdiamond.com).

Photo 4 shows a grouping of black granite tiles that were side cut to accept a decorative tile with a gold luster finish. The photo also shows how a small core bit was used to make the inlay opening for three gold luster dot tiles.

When making any type of inlay, I prefer to perform any and all cutting tasks before setting any tiles in adhesive. If tiles are to be inlaid into a wood floor, the edges of the wood flooring facing the tiles should be finished with the same sealer or top-coating used on the surface of the floor (this will prevent the flooring from suctioning moisture from the sealant that is installed in this movement joint area). For wood or other tiles, the joint between the inlay tiles and the surrounding materials should be even and uniform.

(Photo 5) After dry-fitting is finished, the author removes two mosaic sheets, spreads thinset mortar with a notched trowel (adding thinset mortar to tight areas with a narrow tuck pointer), and embeds the first mosaic sheet. Another sheet is set aside and the technique is repeated until all the sheets are installed.

Installing the tiles

Uniformly shaped commodity tiles normally follow chalk or pencil layout lines that are relatively easy to plot on a wall, floor, or countertop. With art and decorative tiles, especially those that are hand-molded or irregularly shaped, layout lines are not as effective a guiding tool as simply dry-fitting the tiles prior to installation.

For example, in Photo 5, there is not a single straight or repeating line that can be used to align the tiles. In fact, surrounding the perimeter of the inlay, the wood flooring itself is a mass of changing contours. But as the photo reveals, to keep all the sheet-mounted mosaic tiles aligned, I have dry fit all the sheets of mosaic tiles, and then removed the first two sheets to make room for the trowel and adhesive. Once the first sheet of tiles is installed, I remove additional sheets to spread more adhesive, and continue this way until the entire inlay is completed; thus, no layout lines were used at all for this installation.

(Photo 6) Rather than use a pencil line plotted on the sloped shower floor (a line that generally slows down thinset application) a sturdy, adjustable compass makes a far more efficient layout tool.

Layout lines are great for straight, uniform tiles, but they may not be much help for curves unless a template or other method is used to plot the curved lines. When working with curves, though, I skip plotting layout lines, and instead, use direct measurement with a compass. For example, Photo 6 shows the compass I use, made from a piece of scrap wood and two adjustable trammel points, and anchored and centered to a wood block pressed into the drain opening. As the tiling diameter increases, I switch to a longer beam for the trammel points.

Maintaining a smooth surface is critical for the kind of decorative tile work I like to do. This is especially difficult because there is so much allowable warpage for ceramic tiles, and because the stone tiles in many runs have varying thicknesses. When working with ceramic tiles, I spent a fair amount of time examining the tiles with a straightedge, and culling any that are too far out of plane. During installation, I frequently have to adjust the amount of adhesive beneath each tile so that all sit as flat as possible without unacceptable lippage. Back-buttering can really slow down production, though. I use a different approach when installing stone tiles that results in a floor with zero lippage.

As Photo 7 illustrates, I use a made-for-wood belt sander to grind down differences in the heights of the 1 3/8-inch stone mosaic tiles used to cover the floor. Since I don’t waste any time adjusting to the “z” axis (the height of the tiles), these sheet-mounted mosaic tiles were installed in under an hour. To avoid damaging the tiles, I grind them flat before grouting. I can easily duplicate a honed finish on softer stones using only 50-grit belts that wear down quickly and don’t gouge. To finish this floor (Danby marble), I used a 120-grit sanding disk to remove any visible belt marks.

The same basic technique can be used for most soft stones with a honed finish. For working harder stones, or producing a high-gloss finish, special wet-tooling and graduated diamond disks are required.

(Photo 7) The soft, honed-finish Danby marble hexes used to cover this floor are perfect for one of the author’s favorite stone tile installation tricks: using a contractor’s portable belt sander, fitted with standard, carbide belts, to eliminate lippage. The surface of this floor will be further smoothed with a 120-grit disk sander.

Grouting and finishing

One of the biggest obstacles to art and decorative tile work is the lack of an extended color selection. Compared to paint, grout is available in a very limited range of colors. Even worse, cement dyes that are commonly available are dull and uninteresting, and look too simple and basic. I stopped using cement dyes a long time ago. For most multi-colored tile installations I tend to specify natural cement gray grout which tends to “disappear” among the colors, but when I need a special color grout, I head for the paint store. Actually, I first stop off at my tile supplier to buy a sack of non-latex, non-polymerized snow-white grout (regular or sanded, as needed) that will act as the powder base. Next, I select the paint dealer’s best grade of exterior latex, and select the appropriate color. About a gallon of paint will mix 50 pounds of grout, depending on the grout and paint used. Then I mix the white grout powder with the colored paint to a pack-able consistency, allow 10 minutes for slaking and re-mixing, and grout as usual. This mixture will be very thick, rich, and sticky, and require a bit more work to cleanup. Before committing your mixture to the jobsite, though, it’s a good idea to make a demonstration panel to test your paint/powder combination and how easily it cleans up.

Finding a matching caulk can sometimes be a problem, but I use a kit from Red Devil called Create-A-Color, which features a neutral sealant base, a special mixing device and a hypodermic-type needle. I use the hypo to draw a measure of paint, combine it with the sealant base (I sometimes remove a bit of the sealant and replace with 100-mesh sand, for texture), and use it to fill an installation’s movement joints. 

Resources:
  • TCNA Handbook, ANSI A108, and ANSI A137, available from the Tile Council of North America, www.tileusa.com
  • Create-A-Color, mfg. by Red Devil, www.reddevil.com