How to Finish Backsplash Corners

Prepare the Corners

  • Ensure the backsplash tiles are installed up to the corners. Cut any edge tiles to fit if needed.
  • Remove any debris, old caulk or grout from the corners with a utility knife. scrape and clean thoroughly.
  • Fill any gaps or uneven areas in the corners with thinset mortar. Smooth and let dry completely.

Apply Caulk

  • Use a high quality silicone caulk designed for kitchen and bath. Avoid latex caulks.
  • Load the caulk gun and cut the tip to a 1/4″ opening.
  • Apply the caulk in a steady, continuous line along the corner edges.
  • Use a moistened finger or caulk tool to smooth and shape the caulk into a neat bead.
  • Remove any excess caulk with a damp sponge and allow drying completely.

Install Corner trim

  • Metal, tile or pvc corner trim covers provide a tidy finish.
  • Cut the trim to the proper length using tin snips or a hacksaw for metal, or score and snap for pvc.
  • Apply a small bead of construction adhesive or silicone to the back side.
  • Press the trim firmly into place along the corners and permantly mount.


  • Small mosaic tile bits can be used to cover corner gaps. Arrange them in neat rows.
  • Bullnose edge tiles can be used to continue the tile design over the corners.
  • Decorative wall inserts like beadboard provide a finished corner look.


  • Always thoroughly prep corners by scraping and cleaning before finishing.
  • Apply caulk in a steady, continuous motion for smooth results.
  • Keep a damp sponge handy to immediately wipe up any caulk messes.
  • Use matching grout color caulk for an invisible look.
  • Take time to neatly finish backsplash corners for a polished result.

Finishing backsplash corners properly takes precision but is very satisfying. Well-sealed and trim-covered corners complete the backsplash installation and help protect the edges. With careful attention to detail, you can achieve perfectly framed corners for a spotless finish.

Frequently Asked Questions About How to Finish Backsplash Corners

How do I make sure my backsplash corners are straight?

Use a level and mark guide lines to ensure your corner edges are perfectly vertical. Carefully align tiles and use spacers to maintain even grout lines. Taking time to start with straight corners will make finishing them easier.

What is the best caulk to use for backsplash corners?

100% silicone caulk designed for kitchen and bath provides the most water resistance and flexibility. Avoid latex caulks, which can deteriorate over time. Match the caulk color to your grout for invisible filling.

Should I use corner trim or just caulk the corners?

Corner trim provides extra protection and a decorative finish. However, well-applied silicone caulk can also neatly finish inside corners on its own. Choose based on your design preference and skills.

How do I get a smooth caulk line in the corners?

Load the caulk gun properly and cut the tip to 1/4″ diameter. Apply the caulk in one steady, continuous line without stopping. Use a dampened finger or smoothing tool in one fluid motion. Avoid overworking the caulk.

What kind of adhesive should I use for corner trim?

Construction adhesive or silicone both work well to securely adhere corner trim. Avoid super glue or hot glue, which can react with corner materials. Always follow the adhesive manufacturer’s recommendations.

Should I use bullnose tiles on the corners instead?

Bullnose tiles provide a continuous flow around corners instead of a distinct edge. This is an aesthetic choice and bullnose tiles must be incorporated from the start. Caulk and trim can still be used to finish the bullnose corner edges.

How do I ensure an inside corner gap is watertight?

Carefully fill any inside corner gaps with thinset mortar first and allow to fully cure. Then apply a smooth, thick bead of silicone caulk that seals the corner edge completely. Tool the caulk into the corner seam for best water protection.

What can I do if my corners have uneven areas?

Use thinset mortar to fill and smooth any small dips or uneven spots, allowing complete drying first. For larger corner gaps, cut small tile pieces as shims to build out the area before finishing with caulk and trim.

Finishing backsplash corners properly is an important finishing touch that keeps edges sealed and protected. With the right materials and techniques, you can achieve perfect corners that frame your backsplash beautifully.

In summary, good corner finishing starts with proper preparation like cleaning and removing debris. Applying quality caulk or corner trim seals and covers the edges neatly. Take your time to ensure straight corners, smooth caulk lines and trim properly adhered. Your attention to detail will provide polished backsplash corners and a spectacular kitchen focal point.