How to Install Mosaic Glass Tile Backsplash

Installing a mosaic glass tile backsplash can transform the look of your kitchen or bathroom by adding a colorful, eye-catching focal point. Mosaic tiles are made up of small, individual tile pieces arranged in a pattern to form an image or design. Glass mosaic tiles provide a glossy, sleek finish and reflect light beautifully. With some planning and preparation, you can easily install a mosaic glass tile backsplash yourself as a weekend DIY project.

Choose the Right Mosaic Glass Tiles

The first step is to select the mosaic glass tiles. There are many options to choose from:

  • Tile material – Glass tile mosaics can be made from stained glass, machine-cut glass, or a mixture. Stained glass tiles give an artisan, handcrafted look. Machine-cut glass has a more uniform appearance. A combination provides nice visual texture.
  • Tile size – Smaller 1/4” to 1/2” tiles form intricate mosaics. Larger 1” tiles create a bolder statement.
  • Color – Consider a single bold color or an array of multiple colored tiles that blend together. Iridescent and metallic glass tiles add luminosity.
  • Design – Many mosaic sheets come in mesh-mounted panels with decorative patterns. Or you can create your own design with individual loose tiles.
  • Borders – Accent the mosaic tiles with borders in a complementary color or mirrored mosaic design.
  • Accessories – Mosaic tiles can be combined with glass subway tiles, ceramic tiles, stone tiles, or metal tile trim.

Select tiles that match your kitchen or bath’s color scheme and style. Order about 10% extra to allow for cuts, waste, and future repairs.

Prepare the Surface

Mosaic tile can be installed on surfaces including drywall, plywood, existing tile, cement board, or concrete. The surface must be clean, dry, and free of damage, grease, and debris. Painted surfaces should be lightly sanded. Ensure the surface is flat and plumb.

On surfaces that lack water-resistance like drywall, install cement backerboard first according to manufacturer’s directions. Thinset mortar adheres much better to cement board than regular drywall.

Before tiling, seal porous surfaces like cement board with a waterproof membrane or primer to prevent absorption of moisture from the thinset mortar.

Layout Your Design

Map out the tile layout starting in the center and working outward. For a focal point over a cooktop or sink, dry fit tiles to find the optimal placement. Mark the surface with a pencil to indicate the tile placement.

If installing sheets of mosaic tiles, ensure edges will align between sheets and the pattern matches up. Use plastic tile spacers between tiles to help guide consistent spacing and alignment.

Measure and mark any partial tiles that will need to be cut around fixtures, edges, outlets, or switches.

Prepare Materials

Gather all necessary materials before starting installation:

  • Mosaic glass tiles
  • Thinset mortar adhesive
  • Notched trowel
  • Grout
  • Grout sealer
  • Caulk
  • Tile spacers
  • Tile cutter
  • Mixing bucket
  • Grout float
  • Grout sponge
  • Tape
  • Safety gear – gloves, goggles, knee pads

Spread the Thinset Mortar

Wear gloves and safety goggles when handling thinset mortar, which contains silica dust.

Prepare the thinset mortar adhesive according to package directions, mixing it to a smooth, lump-free consistency. Allow it to slake (sit) for 10 minutes, then remix before using.

Use a notched trowel to spread a thin, even layer of thinset onto the surface area where you’ll be installing the first section of tile. Spread just enough that you can tile over within 30 minutes before it skins over.

Set the Tiles

If working with mesh-mounted mosaic sheets, remove the protective plastic from the paper mesh backing.

Press the tiles firmly into the thinset with a slight twisting motion. Use plastic spacers to maintain even grout line spacing of 1/16” to 1/8”.

If the mosaic sheets are not mesh-backed, set individual tiles one by one. Keep the spacing consistent using tile spacers.

Push each tile to ensure full contact with the thinset for optimal adhesion.

Finish Installing the Field Tiles

Work in sections of a few square feet at a time so the thinset doesn’t dry out before the tiles are applied. Continue spreading thinset and setting tiles section-by-section until the field is completed.

Be sure to continually check alignment and spacing as you go. Use a level to ensure tiles are even.

For cut tiles around fixtures or edges, measure and mark tiles to the correct size. Cut the tiles using a wet saw or tile cutter. Set cut pieces using thinset.

Let the thinset fully cure for 24-48 hours before grouting.

Grouting the Tile

Mix the grout according to package instructions, to a thick, smooth consistency. Apply grout over the tiles using a rubber grout float, pressing grout into joints.

Be sure joints are fully packed flush with grout. Go slowly and methodically, keeping grout lines clean as you go. Let grout firm up slightly for 10-15 minutes.

Use a damp grout sponge in a circular motion to smooth grout and clean off excess from the tile surface. Rinse the sponge frequently.

Cure grout for 72 hours, keeping it damp by spraying occasionally with water.

After grout is fully cured, apply grout sealer according to manufacturer’s directions to protect from moisture and staining.

Finishing Touches

Once all grout has cured, inspect the tiles for any haze or film. If needed, clean tiles with a mild acid tile cleaner.

Use caulk between the mosaic tiles and any surrounding surfaces like the counter or walls. This allows for expansion and contraction without cracking grout.

Finally, enjoy your new mosaic glass tile backsplash! With proper care, it will provide many years of beauty and function.

Frequently Asked Questions About Installing Mosaic Glass Tile Backsplash

What type of thinset should I use for glass mosaic tiles?

Use a premium-grade, polymer-modified thinset mortar suitable for glass tile. This type contains polymers that make it super-adhesive and more flexible. Consult the tile manufacturer’s recommendations.

How soon can I grout the tiles after installing with thinset?

Allow the thinset adhesive to fully cure for 24-48 hours before applying grout. This ensures tiles are firmly bonded.

What color grout should I choose?

For glass mosaics, white or very light gray grout provides the best contrast with the tiles and makes the design stand out. Dark grout can make the tiles look dingy and obscure the pattern.

Can I use sanded grout with glass mosaic tiles?

No, only use unsanded grout. Sanded grout can scratch the smooth glass and get trapped between mosaic tiles. Unsanded grout has a polymer additive for adhesion.

Do I need to seal the grout?

Yes, apply a penetrating grout sealer after the grout has fully cured for 72 hours. This adds water-resistance and stain protection. Re-apply sealer annually.

How do I cut mosaic glass tile?

The best tool for cutting glass mosaic tiles is a wet saw with a diamond blade designed for glass. For intricate cuts, you can also use a handheld tile cutter or nipper pliers. Use caution – glass can shatter. Wear safety goggles.

Can I install glass mosaic tile over existing ceramic tile?

Yes, as long as the original tiles are well-adhered and provide a smooth, clean surface. You may need to use a leveling compound to fill any dips or uneven areas first. Always use a premium thinset suitable for glass.

How do I remove old grout before re-tiling a backsplash?

Use a rotary tool or oscillating multi-tool to scrape out the old grout line by line. Be careful not to scratch the surface. Use painter’s tape along edges as a guide. Thoroughly clean off tile surfaces before re-tiling.

Should I use tile backer board or cement board behind a glass mosaic backsplash?

Cement backerboard is highly recommended as a base for any tile backsplash. It provides a water-resistant, stable surface for the tile to adhere to. Follow manufacturer’s directions for installation before tiling.


Installing a glass mosaic tile backsplash requires careful planning, precision, and patience. With the right materials and proper technique, you can transform your space with beautiful, radiant mosaic tiles. Take your time to lay out the design, prepare the surface, spread adhesive, set the tiles, and grout for a flawless finished project. Refer to this guide for tips every step of the way. Once complete, your mosaic backsplash will be a stunning focal point providing the “wow” factor in your kitchen or bath for years to come.