Frequently Asked Questions

Can glass tiles be installed in areas of high heat, for instance around a fireplace, or around a range?
Glass tiles are melted in high temperature kilns, and therefore are naturally heat resistant. As long as there is no direct exposure to a flame, and clearance requirements are met, the tiles will not be adversely affected in areas of high heat. Note, however, that grouts may degrade when exposed to heats in excess of 100 degrees Celsius. Also see caution below about cold painted tiles that do not resist heat.

Does it matter how a glass tile is colored?
Color is typically mixed with molten glass, or is applied to the tile and then fused by firing. Color that fires in is stable, will not fade, delaminate and resists effect of moisture and aging. 'Cold' applications of color to an otherwise finished tile may be at risk. Unless the color is fused into the tile by firing it is liable to fail during or after installation. The most common problem occurs when the cold applied paint contacts thinset and moisture, causing it to discolor and delaminate. Check with the manufacturer.

Should glass tiles be tempered?
No. Tempered glass can not be cut or trimmed during installation.

Can I use glass tiles outside?
Yes. Glass tiles are similar to other glass products, such as windows. They are non- absorbent, and have a very high tolerance to freeze/ thaw conditions. They are also very resistant to acid rain and the fading caused by ultra violet rays and chemicals. Like their ceramic tile counterparts, glass tiles do not tolerate heavy impact, and the result may be more visible.

All sizes of glass tiles may be used outdoors. Mosaics are often used in pool and fountains, where they can be shaped around the objects they cover. Large glass tile may be used in walls and floors, provided they are not exposed to high impact and meet slip resistance criteria for floors.

In all cases, proper construction methods must be observed, such as installation over stable substrates, the use of flexible thinsets, proper use of expansion joints and crack suppression membranes. Consult your manufacturer for details.

Can I use glass tiles on floors?
There are several glass tiles suitable for floors on the market today. Be sure that the tile is actually indicated for floors. The suitability of a glass tile depends on its properties - small mosaics are generally used because the many grout lines make the tile naturally slip resistant. Large format tiles are thicker and often can be found with slip resistance surfaces embossed on the surface. In every case look at the traffic conditions and consult the manufacturer's specifications.

Can glass break off, making it hazardous as a floor or wall covering?
Glass can potentially break out of a tile, but this is rare. Wheras the weaker ( ceramic) substrate on ceramic tiles can mean the glass glaze on top of them can flake and split off the surface, glass tiles tend to have a more consistent density, meaning that all things being equal, the layers are less likely to separate. And if there is also a bonding agent at the back of the glass, this provides more of a platform for containing breakage.

Glass floor tile, with hammer mark.

In practice it's rare to have pieces of glass chipping off a glass tile on impact; nevertheless, glass can break if hit with extreme force and should the pieces of tile shatter, there is a potential for injury.

What about thermal shock resistance?
Glass tiles are more vulnerable to very sudden and extreme temperature fluctuations than ceramic tiles, so the degree of thermal shock that the tile is liable to be exposed to has to be considered for each install. This is especially true if the tiles are going to be placed in sunny outdoor locations where the tiles are likely to be shocked with cold water.

Is it OK to install directly over plywood?
No. Plywood is not considered stable enough to for any tile installation. Cement backer board expands and contracts less, and is a better substrate material. In dry areas, drywall may also be used. In every case a moisture or crack-suppression membrane is always recommended. Note that in many cases manufacturers will not warrant any claims for cracking if a crack-suppression is not installed. See the installation page for substrate information.

Can I use mastic to install glass tiles?
No. Only white, fast-setting, polymer-modified thinset should be used. Why? Thinset is made with sand, cement and additives that react chemically, bonding even while wet. Mastic, on the other hand, bonds only as it dries. When the mastic is trapped between glass and the substrate, the mastic around the edge of the glass dries and seals the rest of the water under the tile. The mastic remains wet and soft forever. Since mastic re-emulsifies when exposed to moisture, mastic should never be used in wet areas.
Note: Do-it-yourself stores now offer a product called “Pre-mixed Thinset”. Unfortunately this is a play on words designed to confuse the consumer. This product is nothing more than a re-branded mastic.

We installed glass tiles 6 months ago, and now a few pieces are breaking. What’s going on?
The answer probably lies underneath the surface. For clues, look at the type of cracks. For example, if a crack has developed across two or more tiles, then it is likely that the substrate is giving way. If the cracks are isolated to individual tiles, expect the adhesive to have been applied incorrectly (too thick and too wet) and now the shrinking adhesive is causing stress on the glass.
Only install glass tiles over stable substrates and follow the manufacturer’s instructions regarding the installation of a crack-suppression membrane and the proper use of thinset.

Should I seal the tiles?
Glass tiles are impervious, so they will neither benefit nor suffer from the application of a sealer. A tile that contains an amalgam of glass and other products are usually impervious as well, though if you are in doubt, to check with the manufacturer.
If a cement based grout is being used in an area where it could potentially come in contact with materials that could cause staining then that grout should be sealed. In many areas if you're sealing the grout it is just as easy to continue spreading the sealer over the entire surface of the adjacent glass tile - excess sealer can be wiped off of the surface of an impervious tile.

How do I clean glass tile?
Usually a soft cloth and water will clean a glass tile. For stubborn dirt, commonly available commercial ceramic tile cleaners may be applicable - check with the manufacturer for recommendations.