Grouting a Glass Mosaic Tile Backsplash

Wait at least 48 hours, after installing the glass mosaics, to ensure that the mortar has dried. Glass is a non-absorbent material; it cannot absorb the moisture from the mortar to help dry it out, so the moisture must escape through the many grout lines in the installation.

Scoop up a fist-sized amount of sanded grout onto the end of an epoxy grout float and press it onto the tiles. Turn the float so it sits lengthwise on the tiles at a 45-degree angle to the backsplash. Drag the float across the backsplash from multiple angles, covering all of the tiles and their joints with grout.

Turn the float closer to 90 degrees from the backsplash and scrape it across the surface of the mosaics. This will remove any excess grout from the tiles but not from the joints. Inspect the installation carefully and press extra grout into any joints that were missed on the first pass.

Let the grout dry for 10 minutes then work a slightly dampened grout sponge in a circular motion over a small section of the tiles. Turn it over and rework the same section. Rinse the sponge and continue to work it over the glass until the excess grout has been removed from the surface.

Wait two hours then buff the surface of the glass with a soft cloth to remove any grout haze. Wait 24 hours before reinstalling outlet covers or getting the backsplash wet. The grout will continue to dry for two to three weeks.

Fill in the corners and right angles of the installation with a thin bead of sanded caulk that matches the grout in color. Squeeze a thin line of it into the corners then use your finger to smooth it into place.