Substrates need to be clean, stable, plumb & true, and also free of dirt, stains and solvents. Cement or cement board are preferred. New cement will be 90% stable within ten days of pouring, but further shrinkage and crystallization will continue, New cement substrates can be tiled over after ten days, if the substrate is first covered with a crack suppression membrane.
Do not install glass tiles directly over plywood or drywall.
If the substrate has small intermittent cracks they can usually be controlled by applying a crack suppression membrane. Large cracks may point to wall, floor, or building integrity - consult an engineer for an assessment.
Acrylic modified thinset on cement fibre wallboard is an effective and simple alternative to a thick cement mud pack. Cement boards are also well cured for shrinkage.
Prepare the surface by removing all dirt, curing compounds, sealers, mortar, etc. In most cases a wire or nylon brush will do the job. Residue from persistent chemicals such as curing compounds or sealers can be removed by bead blasting or sand blasting. Substrates should be true within 1/8" (3mm) in 8 feet (2.4m) for walls and 1/8" (3 mm) in 10 feet (3 m) for floors. Before leveling a surface, wash dry or dusty surfaces and remove excess water.
Compounds that may be needed to adequately prepare the surface include a leveling mortar acrylic compound (to correct surfaces that are not plumb and level), a substrate build-up product, and a patching product.
Crack suppression membranes are not new: for centuries, an asphalt layer has been applied between large-format tiles and the substrate beneath them, to provide a buffer protecting tiles from movement beneath. They are recommended for any glass tile either whose thickness exceeds 4 mm, or whose surface are is greater than 2 inches (50 mm) square. Some manufacturers recommend applying a membrane under smaller format tiles as well: they are easy to install, represent a very small portion of the cost of installing glass tile, and provide added protection against shifts in the substrate.
There are two basic membrane types: peel-and-stick sheets that are cut and rolled on, and compounds that are troweled on. Consult your dealer for the manufacturer's recommended supplier and specific application instructions.
In some cases it may be easier to mark tiles with the needed cuts and take the tile to a professional glass shop for cutting or drilling. However, if you have the right equipment for the right cut, cutting glass tile can be very straightforward. There are three types of cut, each requiring different equipment:
1. straight cuts, standard thickness
2. straight cuts, thick, etched or textured tile
3. curved or irregular cuts.
Always use protective eye wear when cutting tile.
Straight Cuts: Standard thickness (4 mm) smooth glass tile.
For edge-to-edge cuts of 1" or larger on standard thickness (4mm) smooth tile , use a glazier's scoring tool and a straight edge.
For step-by-step instructions, refer to our 'Using a Glass Scoring Tool' photo tutorial.
Straight cuts: for either thick, etched or textured tile
The main method for larger, etched or textured tiles is to use a wet saw, equipped with an electroplated diamond glass-cutting blade.
For step-by-step instructions on wet saw cutting, refer to our 'Cutting With a Wetsaw' photo tutorial.
Curved or irregular cuts: Glass nippers, used on smaller tiles.
Nippers are easy to use and are good for smaller tiles or cuts whose edges will be concealed by a rim or fitting.
Nippers are not precision tools, and on larger tiles they are often impractical. Ring saws, band saws or reciprocating wire saws designed for glass are the simplest tools for cutting exact curves onto glass tiles. These tools can be expensive. It may be simpler to take the tile into a glass shop for cutting or to use coring drill bits creatively.
Drilling: a diamond tipped coring bit is recommended for glass tiles.
The drill is water cooled and set at a slow speed.
For step-by-step instructions, refer to our 'Drilling Into Glass Tiles' photo tutorial.
Breaks in the tile field are required on most large area installations to compensate for variable rates of expansion between the substrate and the tiles above it. Expansion joint requirements depend upon several factors, including climate and substrate, and are specified by an architect.
Insert joints wherever two different substrates abut. For glass wall tile, leave a 1/4 in. gap between the perimeter tile and the wall. Expansion joints should be filled with caulk after the tiles are grouted. There are standards, such as ANSI's 108 AN 3.7, that give advanced instructions on expansion joints.
The thick set method was developed more than two thousand years ago and remains virtually unchanged to this day. Tile is pressed into a thick mixture of sand, cement and water, then vibrated into position - to disperse air pockets and enable good contact with the tile backing. This method is sometimes used with small-format glass tiles. However,glass tiles will not shrink along with the cement mixture: during drying there can be a breakdown in the bond to the thickset, or breakage in the tile itself.
Developed over the past thirty years, thinsets can be highly suitable setting materials for glass tile. Mixtures of sand, cement and either latex or acrylic, these polymer-modified adhesives are very strong, and can be applied in a thin coat.
Mastics, mixtures of latex and organic fillers, have sometimes been used in glass tile setting. Caution: using these latex adhesives can result in glass tile intallation problems. They bond when their dissolved liquids dry out. Unlike cementatious acrylic thinsets, when mastics are used to install glass tiles, and there is a membrane under the mastic layer, the moisture will not disperse properly. Discoloration, mold and other problems relating to the mastic can cause the job to fail.
Always consult your dealer or adhesive manufacturer to get the right adhesive material for the job.
Applying the Thinset
Use the flat side of a notched trowel to apply a layer of thinset to the substrate.
Use the notched side of the trowel to comb the thinset into a uniform depth: do not overbuild the thinset layer.
Many manufacturers recommend small-notched trowels for almost all plumb surfaces. Thin-set manufacturers generally advise that it is not necessary to have a greater thickness of thin-set behind a large tile to create good bond with a flat-backed tile. Apply a uniform coverage to ensure there is complete contact of the thin-set.Consult your dealer or manufacturer for the appropriate trowel size for the job.
Put down only as much adhesive as can be tiled within 10-15 minutes - thinset adhesives dry very quickly.
Use the flat edge of the trowel to "back-butter" a very thin coating of adhesive onto the back of the tiles. This will ensure a good bond, and will prevent notch marks or bubbles in the thinset bed from showing through the tile.
Skim the notch marks flat if the tile is transparent, so that the stripes of thinset are not visible.
Pressing tile into the thinset
Plastic spacers can create uniform joints between tiles. Desired joint widths can vary, depending on the type of tile and desired look.
Once the tiles are in place, tap them flat with a grout float, rubber mallet or padded bar. After setting a section, gently clean up any thinset that has squeezed up between the tiles, using water and a nylon brush, cloth or damp sponge. If you are laying translucent tiles, take care not to scratch the tile's surface.
Thinsets usually require at least 24 hrs for curing at 10 to 30 C. Low temperatures retard the curing time of tile adhesives.
Grouting - step 1
Prior to grouting, tiles should be dry and the thinset adhesive firm.
Sanded grouts may scratch the surface of some tiles. Non-sanded grouts are preferable for narrow grout joints - consult your dealer or manufacturer for the right grout for your tile and installation.
Use a grout float to apply the grout, making diagonal and back-and-forth movements to work the grout in. Use the end of the grout float to press in the grout. For translucent tile, grout joints should be filled to less than the thickness of the tile. This allows light to reflect on the tile's internal surfaces, which will enhance the tile's luminescence.
Grouting - step 2
While the grout is still fresh, use the long edge of the grout float to scrape off the excess. Follow up with a wet sponge.
The day after installation, remove any grout film or haze using a soft cloth and mild detergent solution. If the tile has been installed in an area that will be in contact with oils, such as kitchen stove backsplashes, the surface of the tile and the grout should then be sealed with a penetrating tile sealer to facilitate subsequent cleaning.
Curing the grout
Grout should be damp cured for at least seven days before the tiles are subjected to physical impact - in the case of glass floor tile, this includes construction traffic of any kind. If the installation is a submerged or heavy water-use application, such as spas and swimming pools, the grout should cure 21 days before use.
For more information, consult our Installation/Technical page.
Information on these pages is offered as a background and guideline. No warranty is implied. Always consult manufacturer instructions.