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Glass tile questions
General Technical Properties (information provide by About Glass Tile)
Glass tiles are frost proof, resistant to fading, discoloration, and chemical damage, and are impervious to water and stains. These properties make them suitable for home use, including backsplashes, swimming pools and spas, and various outdoor applications.
Because they contain glass, these tiles can also be more susceptible to chipping and cracking than ceramic tiles. They can disintegrate if they are not installed correctly, if placed in an area where they are exposed to sudden & extreme temperature change, or if they come in violent contact with hard metal objects. Always check with the manufacturer for specifications before you install.
Production methods, combined with color, size and shape, determine a tile's look and feel. For people buying for a surface application, creating a mosaic, or generally curious about how things are made, the main production methods are outlined below.
There are four main types of glass tile: smalti, fused, sintered, and cast. In addition, there are two prominent glass surface treatments for these tiles: slumping and etching.
Below, we display slides made with different production methods, followed by some notes on each type of tile.
Fused TileIn the fused manufacturing method, flat glass (usually float glass, such as glass used on car windshields) is cut into tiles shapes and then fired in a furnace. As glass is clear, it will show the tile underpay unless treated with color, so this method usually involves the addition of color – by adding it on top or under the glass. Fused glass tiles are often translucent tiles, with a layer of opaque color visible through the tile. Fused tiles are often treated with an etching or other coating, for aethetic reasons, or to increase resistance to abrasion. Fused tiles can come in virtually any size – from mosaics to large format. |
Smalti TileSmalti tiles are typically colorful, textured, small format tiles – good building blocks for artistic mosaics. “Smalti” is an Italian word, and refers to a glass paste or glaze made up of silica melted with sodium or potassium carbonate. Metals are added as stabilizing agents, as well as metal oxides ( for color). The paste is fired at high temperatures, then rolled out into a pancake-like slab that can be up to 6 inches thick. Once cooled, the slab is traditionally hand-cut into small rectangular pieces of tile. |
 TerrazzoDeveloped in the 15th Century, marble terrazzo made use of scraps of marble by traditionally bonding them with clay, and sealing them with goat's milk. The resulting flooring was then ground and polished smooth, then finished with wax, linseed oil, and turpentine. Terrazzo flooring was often used on outdoor terraces ( ‘terrassa’ in Italian), where this technique got its name. In the modern era, clay has been replaced by Portland cement. Coupled with the development of industrial grinders, this flooring technique has become more cost effective and commonplace. More recently, there has been new interest in glass surfaces, and the development of modern epoxies, polyesters, latex and acrylics have made it possible for manufacturers to introduce glass into new surfaces. Now terrazzo is available using recycled glass, instead of marble. Glass terrazo is now available for any number of institutional settings, and is also used as a residential floor surface. |
 Cast TileCast tile is made by inserting chunks of glass into a mold. The mold is heated until the pieces melt into each other and become a coherent mass. The result is a layered look. Most recycled glass tile products are made using this method. Terrazzo glass tile is a cast method that combines an concrete amalgam with glass. |
 Slumped TileSlumped glass has been curved into a convex or concave shape during firing. Slumping is usually achieved by melting plate glass into relief molds at relatively low firing temperatures. On cooling, the glass assumes a distinctive curved or contoured shape. |
 Etched Glass TileEtched glass is a proccess of applying a thin, translucent layer on the surface of a tile. This layer can be achieved through one of three methods: |
Sintered Tile
Sintered glass tile is made by pressing glass powder into dies and then heated until the particles fuse. These tiles are often sold in arrays of 1" × 1" squares, but can come in sizes up to 3" × 3".
In this method, color is either added into the powder or added topically after cooling. Unlike smalti tiles, sintered tiles tend to have a uniform look. With their milky, scratch- resistant finish, sintered tiles are known for their versatility.
Frequently asked questions and answers
Does it matter how a glass tile is colored?
Should glass tiles be tempered?
Can I use glass tiles outside?
Can I use glass tiles on floors?
Should I use mastic to install glass tiles or should I use thinset?
We installed glass tiles 6 months ago, and now a few pieces are breaking. What's going on?
What is the best way to clean these tiles?
We’re doing a glass tile wrap-around backsplash installation, which will leave exposed glass tile edges above the sides of the counter. How can we conceal the grout edge of these exposed tiles?
About the only way that you can disguise the grout & thinset so they're not visible is to use a piece of trim. Some manufacturers sell glass trim pieces along with their tiles. Plastic and metal trim can be found in most tile stores and big box stores, or you shop directly at the Schluter store.
We have just tiled a kitchen wall in glass tiles - a DIY project. Can you recommend a sealant to protect the tiles with?
You don't need a sealer to conver the tiles, as glass tiles are impervious. But for the grout lines: once they have been damp cured (28 days), pick a grout sealer recommended by your local tile distributor, or go to the online Stonetech store. Note: remember to damp cure the grout first, or the grout lines may, in time, dry out and degrade.
I have just had a new concrete pool made. Are glass tiles feasible for this? If so, are there any special materials that I should use?
Glass tiles have become a very popular surfacing for pools, for at least two reasons: 1) glassy surfaces compliment the effect of water, and 2) glass tiles do not fade over time or discolor under normal conditions.
The underlying cement should be cured for at least 28 days, and free of cracks before you begin. Pools are harsh environments because of the chemicals used to keep the water clean; setting materials should be adadptred to these conditions mind. We often recommend the products by Mapei, but defer to your tile manufacturer's specifications.
You will also need waterproofing on the substrate. One reputable manufacturer of roll-on membranes is Schluter. Some membranes also have anti fracture properties, allowing them to buffer against substrate shifts. For wet areas, we generally suggest membranes that have waterproofing as well as anti fracture properties - especially when larger tiles are used. Consult with your tile manufacturer for advice on an installation method that they will stand behind
There is something chalky looking on the surface of my tiles. I haven't been able to remove it. Any ideas?
If the residue is caused by abrasion, it will be difficult if not impossible to remove. Glass tiles should never be scrubbed with abrasive tools or fabrics.
In some cases, minerals from hard water can leave a residue. Try white vinegar sprayed directly to the tile. Rinse and neutralize with baking soda. Some people have had good results with commerical toothpaste - though abrasive, it can be fine enough not to scratch tile. Test it on a less visible piece of tile first. If this doesn't work, try googling manufacturers of descaling products like Descale-it and ask if the product is indicated for your tiles.
The pros sometimes use a 10% solution of muriatic acid. Caution: muriatic acid is a very strong acid. Keep the room well ventilated, wear gloves, and keep the acid away from exposed skin; rinse tiles immediately after use.
Does it Matter How a Tile is Colored?
Color is typically applied to tiles in one of two ways. Either it is mixed with molten glass, or it is applied to tiles and then fused into it by firing. When color is properly applied using either of these methods it will be stable, will not fade or delaminate and will resist the effect of moisture and aging. 'Cold' applications of color to an otherwise finished tile - for instance, painting onto the back of a clear tile with no subsequent firing process - is a cheap method. These tiles may look okay at first, but they will have a relatively high incidence of failure. In fact, unless the color is set into the tile with high heat it is liable to fail during or at some point after installation. Thinset and moisture can cause the tile to discolor and the layer of color may even separate from the tile.
I hear that tempered glass is harder than regular glass. Does this mean that I should look for tempered glass tiles? Should glass tiles used on the floor be tempered?
Glass tiles are not tempered, for good reason. First, some background information: tempered glass is a type of toughened glass that has been heated above 600 °C, then rapidly cooled with forced air. This process causes the outside of the glass to become brittle. On impact, the glass will shatter into small pieces and crumble.
As a result, tempered glass can’t be cut or trimmed. It is cut to size before it is tempered; it can’t be re-worked. This makes it unsuitable for tiles, as it can't be fitted to various site conditions.
Glass floor tiles are bonded to solid surfaces, which means that violent follow through is impossible. What is more, the bonding agents that the tile is set enables glass pieces to stick together.
Can I use glass tiles outside?
Yes. Glass tiles, like windows, work well outdoors. 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 any glass, they should be installed away from places of violent or sharp impact.
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, with adequate slip resistance built into the tile. The manufacturer will specify floor-rated tiles.
Can I use mastic to install glass tiles?
We do not recommend mastic adhesives. When mastic is applied between glass tiles and a substrate, the area around the edge of the glass tends to dry and seal in the (moist) mastic that lies directly beneath the tile. Glass tiles are not porous, so this moisture remains trapped; the mastic can remain soft and moist almost indefinitley. Behind clear tiles, this phenomenon results in more than a bonding issue - mold can grow and the tiles can visibly discolor.
We recommend only white, fast-setting, polymer-modified thinset. Thinset is made with sand, cement and additives that react chemically. Note: Beware of a product called Pre-mixed Thinset. This is usually not a thinset material, and is simply 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.
Install glass tiles over stable substrates and follow the manufacturer's instructions. Our experience is that most installation problems can be avoided with the proper use of a crack-suppression membrane and thinset.
What is the best way to clean these tiles?
Usually a soft cloth and water will do: because they are nonporous, glass tiles are typically very easy to clean. For stubborn dirt, commonly available commercial ceramic tile cleaners may be applicable - check with the manufacturer for recommendations.
Sources
Ask Us, About Glass Tile, "http://www.aboutglasstile.com/en/askusPG.php"
Ways of Making Glass Tile, About Glass Tile, "http://www.aboutglasstile.com/en/types.php"
