How to Install Mosaic Tile Backsplash in Corners

Installing a mosaic tile backsplash can add visual interest and color to any kitchen. However, the corners of a backsplash often present some unique challenges during installation. With careful planning and the right techniques, you can achieve beautiful results. Here is a step-by-step guide on how to install mosaic tile backsplash in corners.

Gather the Necessary Materials

Before starting your project, make sure you have all the necessary materials:

  • Mosaic tiles
  • Tile adhesive
  • Notched trowel
  • Grout
  • Grout sealer
  • Tile spacers
  • Tile cutter or nippers
  • Safety gear like gloves, googles and mask

Make sure the tiles you purchase are designed for backsplash use. Smaller tiles like mosaics make for easier corner installation. Also have extra tiles on hand in case you need to replace any that get damaged during installation.

Prepare the Surface

Proper surface preparation is key for a long-lasting installation. The backsplash area must be clean and free of any soap scum, grease or dust. Remove any existing backsplash and make sure the wall surface is smooth.

Fill any holes or uneven areas with spackle and sand smooth. Prime the surface with a tile primer to improve adhesion. Use painter’s tape to mask off any adjacent surfaces you don’t want to get tile adhesive on.

Plan Your Tile Layout

Before starting tile installation, take time to map out your layout. This is especially important when working with mosaic sheets. Measure the backsplash area and sketch out a plan for the tile placement.

For the corners, you want to avoid having to cut mosaic sheets as much as possible. Try to stagger full mosaic sheets so that you don’t end up with small sliver tiles at the corners. Have extra sheets on hand in case you need to re-do corners.

Install the Mosaic Tile Sheets

Once your surface is prepped and layout planned, you can start setting the tiles:

  1. Apply a layer of thinset adhesive using a notched trowel. Spread only a small section at a time so the adhesive does not dry out.
  2. Press the mosaic sheets firmly into the adhesive. Use spacers between sheets.
  3. Continue setting tiles, working out from the corners. Remove spacers once dry.
  4. Let the thinset cure fully before grouting, usually 24 hours.

Take care when setting sheets near corners. Avoid leaving gaps where sliver tiles would be needed. Having extra mosaic sheets allows you to redo corners to optimize your layout.

Cut Any Border or Edging Tiles

Once the main field of mosaic tiles is set, measure and cut any border or edging tiles needed to finish off the installation:

  • Use a tile cutter for straight cuts and tile nippers for curved or irregular cuts.
  • For rounded edges, make a pattern out of cardboard then trace and cut tiles to match the shape.
  • Pre-assemble borders or accents on a work surface using adhesive before installing.

Cutting border and edge tiles takes patience and practice. Having extra tile allows for mistakes. Take your time for clean cuts.

Grout and Seal the Tile

Once all tiles are set and adhesive is dry, you’re ready to grout:

  • Apply grout using a grout float or rubber grout squeegee. Work it thoroughly into the joints.
  • Wipe away excess grout with a damp sponge. Rinse sponge frequently.
  • Once grout has cured, apply a penetrating grout sealer to protect from moisture and stains.

For a mosaic backsplash, an epoxy grout is a good choice as it is more durable and stain resistant. Be sure to promptly clean up any grout that gets on the tile surface.

Tips for Installing Corner Mosaics

Focusing on the corner areas takes some finesse:

  • Avoid L-shaped corner joints by using a vertical offset or stacked bond pattern.
  • Wrap mosaic sheets around corners in a “bookend” arrangement for clean results.
  • Use bullnose edging tiles on outside corners for a finished look.
  • For inside corners, cut tiles to fit or use special corner trims if needed.

Always double check your corners as you go to ensure the patterns and grout lines align properly. Taking time to plan the layout pays off in the end.

Frequently Asked Questions

How do I cut mosaic tiles?

Use a tile cutter for straight cuts and tile nippers for small or curved cuts. Go slowly and score the tile face several times before cutting all the way through. Practice first on scrap tiles.

Should I use spacer strips for mosaic backsplash?

Yes, small spacer strips placed between mosaic sheets help create uniform grout lines and prevent sheets from shifting during install. Remove spacers once adhesive has cured.

What thinset do I use for a mosaic backsplash?

A white polymeric fortified thinset is a good choice for most mosaic tile. It provides a strong bond and resists moisture. Only mix up small batches so it does not dry out.

How long does mosaic tile backsplash installation take?

Expect mosaic tile installation to take 2-3 days – one day for surface prep and layout planning, one day for installing tiles, and another day for grouting once adhesive has cured.

Should I seal my mosaic backsplash?

Yes, apply a penetrating grout sealer to all grout lines after the grout has cured. This will protect from moisture and stains. Reapply yearly. Also use a tile sealer on the tile surface for added protection.


Installing mosaic tile backsplash in corners adds appealing visual elements to your kitchen. With careful planning to map out the tile layout and attention to detail when setting and cutting the mosaic tiles, you can achieve beautiful results. Taking time to properly prepare the surface and allowing materials to fully cure are also keys to a successful long-lasting installation. Use the techniques outlined here and your mosaic backsplash corners are sure to be eye-catching focal points that will provide years of enjoyment.