How to Install Tile Trim Around Internal and External Corners (Step-by-Step Guide)

Tile trims play a crucial role in creating clean, professional finishes — especially at corners where tiles meet. Whether you're a DIYer or a professional installer, knowing how to finish internal and external corners properly ensures durability, aesthetic appeal, and a polished end result.

In this guide, we’ll walk you through:

• The difference between internal and external tile trim corners
• What trim profiles work best
• Step-by-step installation instructions
• Common mistakes to avoid

Internal vs External Tile Trim Corners

External Corners

• Found on outside edges like pillars, boxed-in pipework, and shower walls.
• Usually require a square edge or round edge trim.
• Protect tile edges from chipping.

Internal Corners

• Found where two tiled walls meet inward, such as behind sinks or in shower cubicles.
• Often finished using internal corner profiles or with silicone where needed.

Tools & Materials You’ll Need

• Tile trim (aluminium, chrome, brass, etc.)
• Tile cutter or wet saw
• Mitre box and hacksaw (for angled cuts)
• Spirit level
• Adhesive or tile bonding mortar
• Pencil/marker
• Safety gloves and goggles

How to Install Tile Trim on External Corners

Step 1: Choose the Right Trim Profile

• Common options: Square Edge, Quadrant, or Round Edge.
• Make sure the trim matches the tile thickness (e.g. 10mm or 12mm).

Step 2: Measure and Cut

• Measure the height or length of the corner.
• Use a mitre box to cut the trim at a 45° angle for seamless joins.

Step 3: Apply Adhesive

• Apply tile adhesive to the area where the trim will sit.
• Press the trim firmly into place, ensuring it’s level vertically.

Step 4: Lay the Tiles

• Slide tiles into the channel of the trim while the adhesive is still wet.
• Use spacers to maintain even joints.

How to Install Tile Trim on Internal Corners

Step 1: Use a Suitable Internal Corner Profile (Optional)

• Some trims come with internal corner joints that snap or slide in.
• Alternatively, tile directly into the corner and finish with sealant.

Step 2: Trim and Align Tiles

• Cut edge tiles to fit flush into the corner.
• Use a small gap (1–2mm) to allow for movement or grout.

Step 3: Apply Grout or Sealant

• Use a grout float or sealant gun to fill the gap cleanly.
• For wet areas, use a waterproof silicone (especially in showers).

Pro Tips for a Professional Finish

• Always double-check tile thickness before buying trim.
• When cutting metal trims, use fine-tooth blades to avoid jagged edges.
• Clean excess adhesive before it dries — it can stain certain finishes like brushed brass or copper.
• Dry-fit everything before permanently fixing the trim.

Recommended Trims for Corners

At National Tile Trims, we offer a wide range of trim styles and materials perfect for all kinds of corner installations:

• Wall Tile Edging Trims
• Straight Edge Tile Trim
• Formable Tile Trim – Flexible for Curves

Need help choosing the right profile? Contact us —or browse our full range of tile trims

Final Thoughts

Installing tile trims around corners doesn’t have to be complicated — it’s all about choosing the right profile, making accurate cuts, and applying a steady finish. Whether it’s a sharp external edge or a hidden internal corner, proper tile trim installation adds both durability and elegance to your tiling project.

Next up: Want to learn the difference between 10mm and 12mm trims? Read our comparison guide →