Grouting Glass Tile

Unlike regular glazed ceramic tiles, glass tiles require a little bit different procedure for grouting. Start by cleaning the joints with a razor knife as usual 1.

Use a firm-bristle toothbrush to finish cleaning the narrow joints between small mosaic tiles 2. Work gently, but don’t be alarmed if some tiles pop off during the cleaning process. Just clean the tile by scraping off the thinset from both the back of the tile and from the substrate where the tile popped off. Back-butter the tile with fresh thinset and press it back into place. Clean the entire tile surface with a damp sponge 3.

When applying grout—especially sanded grout—to glass tile, always exercise great caution so as not to scratch the tile (some manufacturers specify nonsanded or sanded grout for their tile, so be sure to check before purchasing). Use a slightly wetter grout mixture than usual and apply it with a soft rubber float that’s specifically designed for use with glass 4. Use a light touch as you apply and spread the grout. If you have any newly reset tiles, it’s best to first grout around them with a gloved finger, and then grout around them with the float.

Since glass is nonporous and set on an antifracture membrane that limits water absorption, grout will take much longer to set up in the joints of a glass tile installation. Therefore, you must be patient and allow more time before wiping down the grout. Instead of 10 minutes, you might wait up to 30 minutes, checking the joint periodically for firmness. Use a soft sponge and wipe down and shape joints much as you would for ceramic tiles 5. After shaping, let the tile dry until a haze forms, then wipe the glass clean with cheesecloth 6.

	1.  Clean thinset from between small joints with a utility knife or a toothbrush.
	2.  The bristles on a firm toothbrush work well to clean joints between glass tiles.
	3.  Clean glass tile with the soft foam side of a sponge
	4.  Apply the grout, then remove as much grout as possible from the face of the glass mosaics with a low-angled grout float.
	5.  Wipe the excess grout from the glass tiles.
	6.  Polish off any grout haze from the glass to leave a shimmering surface.

Replacing a Tile Don’t be alarmed if a mosaic tile pops off while you’re cleaning. Clean the tile by scraping off the thinset with a utility knife. Using a small margin tool, back-butter the tile with fresh thinset. Reset the tile back in its place. Remember its location when you start to grout.

Excerpted from Tiling Complete, 2nd Edition by Robin Nicholas and Michael Schweit.

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