How do I grout or caulk this to prevent splatter from getting in between the tiles and to create a more uniform, traditional tile backsplash look with an 1/8" or 1/4" joint? I'm looking for the least complicated, least messy option.

Thanks!

You certainly can use grout. I would not use more than an 1/8" grout space as it will breakup the picture too much.

Once you have glued all the tiles to the board. Let them cure 24 hours before grouting

- Start with a small section (12 tiles or so)

- Remove all tile spacers

- Dampen the tiles with water and a clean sponge (small kitchen sponge works well)

Apply just enough grout to fill the spaces (joints) between the tiles. Do not cover the entire surface of the mural with grout. (Tip from Linda Paul - use a small flat plastic trowel to place grout on the end of the float)

Holding the rubber float at a 45 degree angle, push the grout into the spaces between the tiles until they are filled.

Remove excess grout using the edge of the float at a 90 degree angle. Be sure to clean out any grout that gets into the surface pits of the tiles (it will not come out if it dries and can ruin the look of your mural)

Clean any excess grout off the tiles using a clean sponge and clean water, avoiding the grout lines.

For smooth joints: use the end of your finger.
or
for a textured rustic look: Take the sponge and pat the grout lines. It’s a great look with the tumbled stone.

Clean the tiles with the edge of the sponge until they look clean! (Not hazy) If there is haze, you can remove it several hours later.

Linda Paul
www.lindapaul.com