Installing marble tile on walls can add elegance and sophistication to any space. Here's a step-by-step guide on how to install marble tile on walls:

1. Gather Materials and Tools:

   - Marble tiles

   - Thin-set mortar

   - Notched trowel

   - Tile spacers

   - Tile cutter or wet saw

   - Level

   - Grout

   - Grout float

   - Sponge

   - Tile sealer (optional)

   - Bucket

   - Mixing paddle

   - Gloves and safety glasses

2. Prepare the Surface:

   - Ensure that the wall surface is clean, dry, and free of dust, grease, and debris.

   - If necessary, repair any cracks or imperfections in the wall surface and allow them to dry completely.

3. Plan the Layout:

   - Determine the layout of the marble tiles on the wall, taking into account any patterns or designs.

   - Use a level and chalk lines to mark the starting point and ensure that the tiles are installed evenly.

4. Mix Thin-Set Mortar:

   - Prepare the thin-set mortar according to the manufacturer's instructions. Mix it to a thick, creamy consistency using a mixing paddle and bucket.

5. Apply Thin-Set Mortar:

   - Using a notched trowel, apply a layer of thin-set mortar to a small section of the wall.

   - Hold the trowel at a 45-degree angle and comb the mortar in one direction to create grooves for better adhesion.

6. Install Marble Tiles:

   - Press the marble tiles firmly into the thin-set mortar, starting at the bottom of the wall and working your way up.

   - Insert tile spacers between the tiles to maintain uniform spacing and alignment.

   - Use a tile cutter or wet saw to cut tiles as needed to fit around obstacles or along edges.

7. Check for Level and Alignment:

   - Use a level to ensure that the tiles are straight and level as you install them.

   - Adjust the position of the tiles as necessary to maintain proper alignment and spacing.

8. Grout the Joints:

   - Once the thin-set mortar has cured (usually 24-48 hours), remove the tile spacers.

   - Prepare the grout according to the manufacturer's instructions and apply it to the joints between the tiles using a grout float.

   - Work the grout into the joints at a 45-degree angle, making sure to fill them completely.

9. Clean Excess Grout:

   - After applying the grout, wait 10-15 minutes for it to set slightly, then use a damp sponge to wipe away excess grout from the surface of the tiles.

   - Rinse the sponge frequently and change the water as needed to avoid smearing grout over the tiles.

10. Seal the Tiles (Optional):

    - Once the grout has fully cured (usually 24-72 hours), consider applying a penetrating sealer to the marble tiles to protect them from stains and moisture. Follow the manufacturer's instructions for application and drying time.

11. Final Touches:

    - After sealing (if applicable), wipe down the marble tiles with a clean, damp cloth to remove any residue and buff them dry with a soft cloth.

    - Reinstall any fixtures or trim pieces that were removed during the installation process.

By following these steps, you can install marble tile on walls and create a stunning, durable surface that enhances the beauty of any room.