Installing Mosaic Tile

Intro

Not long ago, setting mosaic tile meant embedding each small piece in a mortar bed. Later developments, notably sheets of mosaic held together by paper adhered to their face, helped reduce installation time. These early face-mounted sheets, however, were difficult to line up.

Modern mosaics have taken improvements a step further. Each small mosaic tile is bonded to the sheet with plastic dots or on a plastic mesh, paper, or threaded backing.

You'll find mosaics in many colors and in squares, rectangles, random designs, and all forms of geometric figures. Most mosaic tiles are glass or high-fired porcelain, so they're impervious to moisture. Porcelains come with glazed surfaces for walls and with nonslip surfaces for floors.

If the style you've chosen is available only in dot-mounted sheets, make sure the dots are free of any residual manufacturing oil. This oil interferes with adhesive bonding. Check two or three sheets in each carton, wiping them with a paper towel. If replacing a carton is not an alternative, either change your design or wash the back of each sheet with a mild detergent.

Checklist

Time
About five to six hours (not including grouting) for an 8x10-foot room

Tools
Chalk line, tape measure, carpenter's pencil, power drill, mixing paddle, notched trowel, beater block, rubber mallet, 4-foot metal straightedge

Skills
Measuring, setting tile

Prep
Remove existing flooring, repair or replace underlayment

Materials
Epoxy mortar, mosaic tile sheets

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Balanced mosaic pattern, Unbalanced mosaic pattern

Arranging Random Patterns

A mosaic pattern that features randomly placed colored tiles is more difficult to set than one that has regular geometric patterns -- you have to make sure the color schemes throughout the design balance each other.

Lay the sheets on the surface in a dry run, changing their positions until you get the arrangement right. Then take up the sheets and number them so you can mortar them in the same order.

Such experimentation produced the balanced pattern, but this pattern with its centered square is not the only balanced design possible with these tiles. Avoid patterns like the unbalanced one shown. Although it is composed of the same tiles, it appears unbalanced and chaotic.

Step 1

Lay out perpendicular lines in the center of the room, and snap grid lines at intervals of the same dimensions as the mosaic sheet. Mix the epoxy adhesive, and using a 1/4-inch notched trowel, spread and comb it on a small area, just inside the layout lines.

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What If... Mosaic Tiles Need to be Cut?

One advantage of mosaics is that the small size of the individual tiles can often fit around obstacles without cutting them. Use a utility knife to cut the backing in the contour of the obstacle and strip away the tiles. If you need to cut an individual tile, remove it from the backing and cut it with a snap cutter. Then back-butter the cut piece and set it in the mortar.

Step 2

Set the corner of the first sheet just inside the corner of the layout lines. Square the sheet to the lines and embed the tiles firmly into the mortar with a beater block and rubber mallet. Make sure the entire surface of the sheet is level in the mortar -- mosaics show depressions dramatically.

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Keep Colors Consistent

It's impossible to set mosaics without some of the mortar creeping up into the grout joints. To keep your work from looking blotchy when you apply the grout, use the same product for both the mortar bed and the grout -- 100 percent solid epoxy of the same color. Alternatively, you might be able to color the mortar to match the grout, but such attempts often result in noticeably different shades.

Embedding the mosaic sheets into the mortar will inevitably force some mortar onto the surface of the tiles. Before you set the next section, use a synthetic scrubbing pad to clean the tile, then wipe it with a dampened sponge. Don't use too much water -- it will wash out the epoxy from the joint and weaken it.

Step 3

Pull the sheet up and check it for full coverage. If some of the tiles show bare spots, apply more mortar. Lay the sheet face down on a clean surface and skim more mortar on the back. Recomb the mortar bed with a larger notched trowel and reset the sheet with the beater block.

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Step 4

Set the next sheet using the same techniques. After four or five sheets, you should have a feel for the proper amount of mortar. As you embed the tiles with the beater block, make sure the edges of each sheet are flush with its neighbors; then line up all the joints.

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Step 5

Continue setting the tiles, using a metal straightedge to keep the edges straight. Wipe excess mortar from the surface of the tile with a damp (not wet) sponge. Make sure you remove all of the excess -- dried mortar is difficult to remove. Let the mortar set, then grout and clean the tiles.

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