How to Install a Glass Mosaic Tile Backsplash

Greasy splatters and messy spills present no challenge to a backsplash made of tile, one of the easiest-to-clean materials for the stain-prone spot behind a range or sink. And the subtle color variations of translucent glass mosaic tile offer a rich look that makes this area a real eye-catcher in your kitchen. Mounted on 12×12 sheets of paper, the 3/4-inch tiles are simple to install and will fit around cabinets and counters with few cuts. Even better, grouting the tile with a new urethane-based, nonporous product means you won’t need to apply sealant to keep your backsplash looking spiffy. Read on to see how This Old House senior technical editor Mark Powers turned a bland wall into a brand new showpiece.

Tile: 3/4-inch straight-profile mosaic in Clay by Ann Sacks, from $35 per square foot

Grout: TruColor premixed grout in Alabaster by Bostik, about $76 per 9-pound bucket

Step 1

How-to Install a Glass Mosaic Tile Backsplash

Project Timeline

Friday: Prep the wall, apply the thinset, and install the tile.

Saturday: Wait for the thinset to cure for a full 48 hours. Do not touch or clean the tiles during this time.

Sunday: Clean the tile, grout the joints, and caulk the perimeter.

Step 2

Install a Temporary Ledger

Turn off power to receptacles, and install a temporary ledger. Remove the range. Turn off the power to any electrical receptacles on the wall you’re tiling; unscrew and pull them out of the boxes so that you’ll have room to work around them. Lay scrap cardboard on top of your counters against the wall to be tiled to act as a spacer. Affix a scrap piece of 1x lumber to the wall between the countertops, using drywall screws, to act as a ledger. The top of the ledger should be even with the top of the cardboard spacer.

Step 3

Prepare the Wall

While a porous surface such as new drywall or backer board offers the best bond with thinset, you can tile over a painted wall if you first rough up the surface using an 80-grit sanding sponge. If your walls are brightly colored and you’re installing translucent tile, prime the walls with a sealer-primer, like Kilz, before sanding so that the color won’t bleed through the thinset.

Step 4

Mark the Layout’s Centerline

Choose an area that’s a natural focal point, like the spot above a range (which we selected), to start your layout. Measure the horizontal center of this area, and mark this centerline on the ledger with painter’s tape so that it’s visible as you install tile on the wall.

Step 5

Lay Out the Sheets for the Starting Area

Create a work surface by placing a scrap board across the gap where the range was. Beginning at the bottom, lay out a run of sheets horizontally, adjusting them right or left of the centerline to minimize tile cuts at the ends of the starting area. When you’re done with the first run, continue laying out rows of sheets above it, holding sheets up to the wall to measure fit, until you reach the top. Leave a 1/8-inch expansion gap at the perimeter, where the tile meets your cabinets. To further minimize tile cuts, slice sheets that will be installed along the perimeter into strips and “cheat” the strips close together to make room for full tiles. (You’ll have to experiment to get the best fit. And don’t worry that the tile joints are tighter in these spots—they’ll blend in once the tile is installed.) Mark the paper facing of the sheets and strips so that you’ll know exactly where to install them later.

Step 6

Lay Out Sheets for the Remaining Areas

Repeat Step 2B for the rest of the wall, leaving a 1/8-inch expansion gap where the tile meets the cabinets, walls, or counters.

Step 7

Coat the Wall with Thinset

Mix thinset in a bucket. Divide your work area into a few sections. Starting in the focal-point area, use the flat edge of a trowel with a 3/16-by- ¼ inch V-notch to cover the wall with thinset. Use a fanning motion to achieve a relatively even thickness of about ¼ inch.

Tip: Work in small sections so that the thinset doesn’t begin to cure, or “skin over.” If this happens, simply scrape it off, discard, and apply a fresh coat.

Step 8

Comb the Thinset

Using the notched edge of the trowel held at a slight angle to the wall, comb the thinset horizontally. As you work, return the excess thinset that accumulates on the trowel to the bucket.

Step 9

Smooth the Combed Thinset

Notched lines will show through translucent tile, so smooth the thinset with the flat of the trowel, using a downward motion. Don’t remove thinset from the wall during this process. When you’re done, the thinset should be an even 1/8 inch thick on the wall.

Step 10

Place the First Tile Sheet

Using both hands, press the first sheet of tile into place along the centerline, according to the layout you created in Step 2. Apply even, gentle pressure to the entire sheet, and set the tiles in place by holding a block of wood over the sheet and lightly tapping it with a hammer.

Step 11

Install the Field

Continue to add tile sheets to the wall in the focal area, working from the bottom up. When that spot is complete, fill in the rest of the field, working from the centerline outward, then upward. Line up the joints between sheets closely, a bit tighter than the joints between individual tiles on one sheet but not so close that they touch one another. Doing this makes the joints between sheets “disappear” so that the tiles looks continuous on the wall.

Step 12

Make Sure Tiles are at a Consistent Depth

As you add sheets of tile that abut others, hold a block of wood over the joints between sheets and tap lightly with a hammer. Do the same at all corners where tile sheets meet.

Tip: Don’t be tempted to substitute a rubber mallet for the hammer when setting glass tile. Its “bounciness” will cause the tile to shift out of place on the wall.

Step 13

Saturate the Paper

About 20 to 30 minutes after you’ve installed the first sheets, the thinset will begin to cure, but it will still be pliable enough to adjust tiles if necessary. This is the right time to remove the paper facing. To loosen the adhesive, moisten a sponge until it’s wetter than damp but not sopping (it shouldn’t release water when flicked). Blot it onto the facing several times over a period of 5 to 10 minutes.

Step 14

Peel Off the Paper

Once the paper is saturated, slowly peel it off, starting from an upper corner and pulling diagonally. You may notice a few tiles that have shifted out of place on the wall. Nudge them back into position one at a time, keeping your hands wet so that the adhesive residue on the tiles won’t stick to your fingers as you work. Repeat these steps to remove the paper at appropriate intervals during installation.

Step 15

Cut Each Tile

You may need to cut a few tiles to fit around electrical receptacles or other obstructions. To do this, soak a sheet of tile in water and remove the paper facing. Cut individual tiles to size using two-wheeled glass nippers.

Step 16

Install Each Tile

Back-butter a tile with a layer of thinset, and press it into place. Make sure your hands are wet while you work so that the adhesive residue on the tile doesn’t stick to your fingers. Repeat for all tiles. Let the thinset cure for 48 hours before moving to the final step.

Step 17

Clean the Tile

To prepare the wall for grouting, remove the adhesive residue from the face of the tile with a wet sponge. Use a nylon scrub brush to reach the areas between grout lines.

Step 18

Grout the Joints

Stir the premixed urethane grout gently but thoroughly until its texture is uniform. (We used a drill/driver fitted with a paint-mixing bit, at a slow speed.) Let it sit for a few minutes, until any air bubbles have dissipated. Working on one small section at a time, wipe the tile with a wet sponge until the surface is slick. Apply grout using an epoxy grout float, pulling it horizontally and vertically over the tile to work it into the joints. Once the joints are packed, pull the float diagonally across the tile to remove excess from the tile faces, then mold the joints to eliminate high points by wiping the tile in a circular motion with a wet sponge. Remove traces of grout from the surface by lightly wiping a clean, damp sponge diagonally across the tile. Repeat, section by section, for the entire wall.

Step 19

Caulk the Perimeter

Using a caulk gun and the coordinating acrylic caulk for your grout, apply a bead to the perimeter of the backsplash area, where the tiles meet your walls, cabinets, and counters. Let cure for a couple of hours. Reinstall the electrical receptacles, using longer screws if necessary. Remove the ledger before replacing the range.