Grout and Glass Mosaic Tiles: How To Avoid Disasters
Many beginners report spending hours or days gluing down tiles only to
report that they all start coming off when the apply grout. Others
report grout that crumbles or never being able to get all the concrete off
the tiles. Here's how to avoid ruining your mosaic:
- Always test your adhesive on one or two glass mosaic tiles before you spend days
creating a masterpiece. You may occasionally find that the glue
doesn't bond well to the glass or the surface underneath. Simply
allow the test tile to cure overnight and try prying it off in the
morning. (Wear safety glasses as the tile may splinter.)
- Seal porous tile such as tumbled stone and unglazed ceramic tile
BEFORE you grout. This prevents the grout from staining the porous
surfaces. This step isn't necessary with glass mosaic tile because
smooth glass is nonporous.
- Allow the glue to cure for at least 24 hours before you grout.
- Use sanded grout if the gaps between tiles are greater than
1/8" Grout is concrete, and it needs reinforcing the same way
that concrete in roads is reinforced with gravel and iron bar.
This keeps the grout from crumbling.
- Make sure that the surfaces of your mosaic tile are relatively
level. This usually isn't a problem with glass mosaic tile because
most varieties are relatively flat. However, artistic mosaics on
surfaces that aren't flat (such as a mosaic vase) tend to have corners
of tile that stick out. Be gentle with these when you apply the
wet grout so that you don't knock off any tiles. Keep in mind that
wet grout may loosen water-based adhesives. Use a water-proof
solvent-based adhesive if necessary. Cutting the tile into smaller
pieces may also help on rounded surfaces.
- Mix the grout according to manufacturer instructions. Mix
thoroughly. Don't add too much water. The consistency should
be a firm dough.
- Don't let the grout dry out as it cures. Grout is like any other
concrete. It hardens by hydration, not dehydration. After an
hour, mist LIGHTLY with a spray bottle if needed. Don't spray or
- Grout is applied by rubbing the grout into the gaps with a spatula,
trowel or rubber glove. Press the grout in thoroughly and wipe
away the excess. Then make repeated passes with a damp sponge (not
dripping wet). Rinse sponge and repeat as needed. This step
requires more passes and more care if the surface is uneven or the gaps
between the tiles are too large.
- Don't erode the wet grout from the gaps between tiles. This
exposes sharp edges and looks bad.
- The day after you grout, you may notice a residue or haze on the
surface of the glass mosaic tile. Simply buff this haze away with
a clean dry cloth. The last step in grouting is appropriately
Vases, votives and lamps are popular mosaic projects because they don't require any extra work to figure out
how they will be displayed or hung on the wall. However, they do require a LITTLE extra work because they
are usually glass and usually rounded.
Here are some tips for grouting mosaic vases made from glass mosaic tile:
- If necessary, scuff the vase with sand paper to ensure that the glue bonds securely.
- Glue can be runny, and tiles can slide off. Simply lean the vase on the side and glue one side at time.
- Cut the tile small enough so that the flat tile can fit to the rounded vase.
- Make sure the glue cures for 48 hours or more before grouting.
- Grout gently.