How to Finish Edges of Glass Tile Backsplash

Installing a glass tile backsplash can add a gorgeous, eye-catching focal point to any kitchen or bathroom. However, finishing the edges of the backsplash properly is crucial for a seamless look. Improperly finished edges can detract from the beauty of the backsplash and make it appear sloppy. Follow these tips for a professional-looking finished edge on your glass tile backsplash.

Select an Edge Profile

There are several options for finishing the edges of a glass tile backsplash:


Bullnose tiles have one finished rounded edge. Using bullnose tiles on the outside edges of the backsplash creates a smooth, finished look. Bullnose tiles come in many sizes, shapes, and colors to match or coordinate with the field tiles.

Pencil Liner

Pencil liner trim is a narrow trim tile, usually 1×4 inches, with finished edges on the long sides. Pencil liners create a clean border along the sides of the backsplash. Matching pencil liner colors to the field tiles ties the whole backsplash together.

Metal Trim

Metal trim like brass or stainless steel can be installed along the edges of the backsplash as well. This adds visually interesting material transitions from the tile to the wall. Make sure the metal trim is designed for backsplashes and rated for wet areas.

Tile Edge Finishing

Glass subway tiles can have finished “pillowed” edges. Tiling the entire backsplash with subway tiles creates a contemporary minimalist look with integrated finished edges.

Prepare the Surface

Ensure the substrate behind the backsplash is waterproof and properly prepared. Cement backerboard is an ideal substrate for glass tile. The edges should be smooth and even with no gaps or uneven areas.

Fill any dips or inconsistencies around the backsplash area with thinset mortar to create a flat surface. This prevents cracking grout lines or tile popping off later on.

If the backsplash edges are not square or level, use tile edge trim or build out the substrate surface with mortar or cement backerboard to create straight edges.

Dry Lay Tiles

Before applying any mortar or adhesive, do a dry layout of the tiles. Place the field tiles first, then determine where your edge tiles or trim will go. Ensure you have the right amount of edging materials.

Make sure tile edges align with the layout lines and the entire backsplash fits within the space. Adjust the design if needed before adhering anything.

Apply Edge Tiles or Trim

Most glass tiles require setting with thinset adhesive. Apply thinset where the edge tiles or trim will go using a notched trowel.

Push the tiles or trim into the mortar, aligning with the layout lines. Use tile spacers between trim or edge tiles for consistent grout lines.

Check for even coverage of mortar on the back of each tile and proper alignment throughout the installation. Allow the thinset to cure per manufacturer instructions before grouting.

Cut Edge Tiles

For more customized edges, measure and cut edge tiles to fit around corners or work around outlets, windows, or other obstacles.

Make precise cuts with a wet tile saw. Grind or smooth any sharp edges after cutting. The cut edge can face the wall or down toward the counter or vanity.

Apply thinset mortar and install any cut edge tiles in the same manner as the others.

Grout the Backsplash

Once the thinset has fully cured, grout the backsplash. Use sanded grout for glass tile with wide grout lines or walls with some unevenness. Apply grout with a grout float, pressing into the joints.

After grouting, wipe off excess grout with a damp sponge and clean the surface of the tiles. Avoid washing out too much grout from the joints. Allow the grout to dry completely.

Apply Grout Sealer

Sealing the grout after installation prevents staining and damage from moisture. Use a penetrating grout sealer specifically designed for glass tile. Apply sealer with a small paintbrush only to grout lines, avoiding contact with the tile surface.

Allow sealer to penetrate for 5-10 minutes, then wipe off any excess product. Reapply grout sealer on an annual basis or as needed to protect the finish.

Caulk Perimeter with Silicone Sealant

Once grout is fully cured, caulk along the top outer edges of the backsplash using a silicone sealant. Apply in a narrow bead, then tool into the joint with a caulk smoothing tool.

Caulking creates a flexible watertight seal between the tile and wall. Choose a sealant color to match or coordinate with the grout.

Tips for Success

  • Take time to ensure the substrate is perfectly plumb and smooth before installing tiles.
  • Carefully mix grout and mortar products to the ideal consistency.
  • Use tile spacers for even grout lines and straight tile edges.
  • Wipe up any excess thinset or grout from the tile surface immediately to prevent drying.
  • Avoid walking on or disturbing freshly grouted areas until completely dry.
  • Apply grout and caulk sealers in thin coats, wiping up any excess.
  • Check for missing grout or damaged caulk annually and reapply as needed.

A beautifully finished glass tile backsplash can be a focal point and highlight of any space when edged properly. With careful prep and installation of edge details, you can achieve stunning professional-looking results.

Frequently Asked Questions About Finishing Edges of Glass Tile Backsplashes

What are the best edge options for finishing a glass tile backsplash?

Bullnose, pencil liner trim, metal trim, and subway tiles with finished pillowed edges are great options. Choose edges that match or coordinate with the field tile colors and design. Bullnose and pencil liners provide the most seamless integrated edge.

Should I use trim or bullnose tiles to finish the edges?

Bullnose and trim tiles ensure an attractive finished edge versus an exposed rough tile edge. Bullnose has rounded smooth edges on one side. Pencil liner trim goes vertically along the sides. Choose whichever profiles best match the backsplash design.

How do I cut edge tiles for a glass tile backsplash?

Use a wet saw with a diamond glass tile blade to cut any customized edge tiles needed to fit the backsplash area precisely. Make slow, steady cuts to avoid cracking or chipping the glass tile. Smooth any sharp edges after cutting using a rubbing stone. Carefully position and install cut tiles.

What kind of thinset mortar is best for installing glass tile backsplash edges?

Use a white polymer-modified mortar formulated for glass tile and wet areas. Laticrete and Mapei are excellent thinset brands for glass tile. Apply an even layer of thinset with a notched trowel to adhere edge tiles and trim properly.

Should sanded or unsanded grout be used with glass tile edges?

Either sanded or unsanded grout will work, depending on the grout line width. Sanded grout with some flexibility is best for glass tile with grout lines wider than 1/8 inch and provides stability between tile edges. For thinner grout lines, use an unsanded grout.

How soon can I get the backsplash wet after grouting?

Avoid excessive moisture on the backsplash for at least 3 days after grouting to allow proper curing. Limit cleaning to only light wiping during this period. After 3 days, the grout should be fully cured so you can clean the backsplash normally and get it wet or damp without issue.

Where exactly should I use caulk on the finished backsplash?

Apply a bead of silicone caulk along the top outer edge of the backsplash where it meets the wall. Tool the caulk into the joint for a smooth finished look. Caulk creates a waterproof seal between the tile and wall along any exposed edges or gaps.


Finishing the edges of a glass tile backsplash properly gives a clean, polished, professional look to the entire installation. Using bullnose or trim edge tiles, precision cuts, high-quality grout and caulk, and careful technique will result in stunning finished edges that complement the backsplash design. With the right edge treatment, a glass tile backsplash can become a focal point that transforms the space.