Frequently Asked Questions

Surfaces such as concrete and plywood floors can experience minor movement due to settlement or just normal expansion and contraction. When this movement occurs, cracks in the substrate can be transmitted to the tile installation, causing cracks in the tile or grout. Custom has several mortars with built-in flexibility to withstand minor movement up to 1/16". The best insurance against cracking is to apply RedGard to the surface before installing the tile. For concrete slab installations, use RedGard then bond the tile with FlexBond for a Lifetime Warranty installation.

Yes, provided that the floor has a tongue and groove subfloor with an additional layer APA exterior grade plywood on the top being nominally 1 ¼” thickness and is built to tile industry standards. However, plywood it is not a stable surface as it will expand and contract. If bonding to plywood, a polymer-modified mortar that meets ANSI A118.11 standards is required. As a superior alternative to bonding directly to plywood, we recommend WonderBoard Lite. Backerboard is installed with a latex modified mortar directly over the plywood subfloor and fastened with 1 ¼” coated backerboard screws and then tile is bonded to the backerboard. Cement backerboards are easier to bond to and provide a more stable surface. We offer a Lifetime Warranty over backerboard installations with many Custom mortars and grouts.

Cement backerboards such as WonderBoard Lite are made of cement to offer a very stable surface that won't warp or deteriorate. Cement mortar bonds extremely well to cement surfaces, so you can be assured of a superior bond. Backerboards are impervious to water damage even when exposed to continuous moisture, so they can be safely used in wet area installations. Many materials such as plywood, drywall and even water-resistant drywall can be damaged and will deteriorate when exposed to continuous moisture. Backerboards are also a superior alternative to bonding directly to a plywood subfloor. Plywood is not a stable surface and will expand and contract with climate changes. Backerboards provide a more stable surface on which to bond tile.

Backerboards come in two thicknesses: ¼" and 7/16". ¼" backerboards are used for floor and countertop installations. They reduce subfloor modifications to adjacent floors, thresholds, carpet and cabinets. 7/16" backerboards can also be used on floors and countertops but can also be used for countertops, as well as on walls. They line up with surrounding ½" drywall installations.

WonderBoard Lite panels should be backfilled with a polymer modified mortar and taped with SuperiorBilt Fiberglass Board Tape. Taping all the joints, it reinforces the Wonderboard Lite panels and helps eliminate potential cracking through the tile assembly.

Although not an ideal situation, you can bond to cutback adhesive over concrete slabs when properly prepared. The cutback adhesive must be non-water soluble. The remaining residue must be wet-scraped to transparent. Use caution during preparation, as adhesives may contain asbestos fibers and sanding can result in harmful dust. To enhance the bond of tiles to the concrete, MBP Multi-Surface Bonding Primer can be applied.

Yes. The sheet vinyl must be non-cushion backed, well bonded to the floor, clean and free of all contaminants that would prevent a good bond. We recommend roughing up the floor by sanding. However, under no circumstances should you sand flooring if you suspect it contains asbestos, as harmful dust will result.

Yes, it acts as a filler that helps to flatten the cement board making a more solid surface on which to tile.

Most ceramic tile adhesives have very high bond strengths in dry areas, which makes them excellent for drywall installations. Yet when adhesives are exposed to water, their shear strengths are dramatically reduced. Thin-set mortar bond strengths are less affected by water. As an example, the dry shear strength for OmniGrip is 760 psi and the wet shear is 145 psi. This is why ANSI recommends intermittent water exposure only and interior use for adhesives.

Ceramic tile adhesives can take a considerable time to dry, usually a minimum of 24 hours before applying grout. When applying tile to dense surfaces such as existing ceramic tile, to impervious or vitreous tile such as porcelain, in high humidity, when temperature is below 60°F, or when setting tile over 6" x 6" drying time can be greatly extended beyond 24 hours. Thin-set mortars are preferred in these situations, although ceramic tile adhesives will perform.

Manufacturers typically recommend adhesives more for wall installations; thin-set mortars are preferred for floor installations.

All of Custom's ceramic tile adhesives can be used to set gauged slate, marble and granite tile. All stone must be gauged tile up to 3/8" thick (no irregular backing). Do not use ceramic tile adhesives to set moisture-sensitive, light translucent or resin-backed stone.

Mastic is a viscous material that is commonly used as a gap filler or sealant in the roofing industry. The term "mastic" is also applied to other similar construction industry products, such as pre-mixed ceramic tile adhesives. The American National Standard Specifications for the Installation of Ceramic Tile (ANSI) defines mastics as "organic adhesives" to distinguish them from thin-set mortars, which are inorganic adhesives. An organic adhesive uses a polymer as the bonding agent, whereas an inorganic adhesive uses cement. Generally, "adhesive" and "mastic" are interchangeable terms in the tile industry.

There are two basic types of mortars: polymer-modified mortars and unmodified mortars. Polymer-modified mortars have higher bond strengths and are better than unmodified mortars for use in wet areas. The polymer (or latex additive) is already in the powder, so you only have to add water and mix. Unmodified mortars are adequate for basic tile jobs, such as a residential floor over concrete or a wall tile job when setting ceramic tile. Only water is required for these types of installations. For more demanding installations, a polymer-modified mortar is required. You can use a mortar that is already polymer-modified (latex is in the powder) or an unmodified mortar and a liquid latex additive that is used in place of the water requirement. Installations requiring a polymer-modified mortar are when setting porcelain tile or large tile over 12" x 12", in wet areas, high traffic areas, exterior installations, surfaces that could be subject to minor movement, installing tile over exterior grade plywood, vinyl flooring, plastic laminates or other hard to bond surfaces or setting tile over a waterproof membrane.

Standard thin-set mortars are generally used to install tiles with one side less than 15”. If the gap between the tile and the substrate is likely to be more than ¼” thickness, you will need to use a mortar designed for Large Format Tile. Mortars designed to be used with Large Format Tiles can be applied up to ¾” thick to fill the space between the tile and the substrate. Generally, tiles with one side greater than 15” require a thicker application of mortar to bond and support the tiles properly. Most LFT mortars have non-slump properties to help eliminate “lippage” or unevenness of the tiles as the mortar cures. It is important to achieve at least 80% mortar transfer (95% in wet or exterior application) to the back of the tile. We recommended “back butter” (applying a thin coat of mortar to the back of the tile) in addition to the application to the substrate. This will assure good contact and transfer of mortar to both the tile and the substrate.

Sealer should be used 48 - 72 hours after grouting.

No. Polyblend Grout Renew is basically a pigmented sealer, so it seals the surface while coloring it.

No. Pre-Mixed Grout is suitable for use in dry areas to touch up or repair spots where the grout is missing. A wet area is anywhere that gets frequent and prolonged exposure to water such as around a sink, tub surround, shower or outdoor area.

Minimum 24 hours before exposing to water. Cure time may be extended, depending on caulking thickness and ambient conditions. Polyblend Caulking should always be installed in a dry joint.

Paint will adhere to Polyblend caulking, however it will not adhere to the Commercial 100% Silicone Caulking.

Caulk is designed to be used in "transition joints" or change of plane, where settling or structural movement is possible. Examples are where a countertop deck meets the backsplash, where tile meets the tub, where wall meets floor. Because caulk is flexible, it can withstand any structural movement that may occur without cracking.

100% Solids Epoxy Grout is formulated to be mixed with Polyblend Sanded Grout only.

No. Polyblend Grout is polymer-modified which means the latex additive or polymer is already included in the powder - all you need to do is add water.

Efflorescence, a crystalline deposit that sometimes appears on cement grout as a whitish powder or crust, can occur with any Portland cement based product including grout. This can be removed with TileLab's Sulfamic Acid Cleaner or Grout Haze Remover according to directions. Some natural stones such as marble, limestone or travertine are sensitive to acids. Test cleaners in an inconspicuous area before use. If the stone is sensitive, use TileLab Heavy-Duty Cleaner & Stripper.

Color variations can occur in any Portland cement product including grout due to uneven drying of the cement in the grout. Color variations can be minimized by following directions and using as little water as possible for clean-up. The best way to correct color variation is with Polyblend Grout Renew that is available in all Polyblend grout colors. For the best color consistency, choose Fusion Pro Single Component Grout or Prism Color Consistent Grout.

Grout shading is when colored grout dries to its expected color in some areas, a darker color in some areas and varying shades in between. This is most commonly caused by uneven drying of the Portland cement in the grout due to differing tile types, tile porosity, jobsite conditions, and application/cleaning techniques. Concrete is also made with Portland cement. It is not uncommon for concrete driveways, slabs, etc. to exhibit some discoloration and shading and this is true of grout. This is an accepted fact with concrete, but since grout is primarily used for decorative purposes, shading provides an unwanted look to the installation. Grout shading can be minimized by following these installation tips:

  • Tile must be securely bonded and allowed a minimum of 24 hours curing time before grouting. Be sure to remove all spacers.
  • Grout joints should be uniform in depth and width and excess mortar should be removed.
  • Dry-mix grout powder before mixing with water. Mix with proper amount of cool, clean water. Do not add too much water. Keep the water to powder ratio consistent between batches.
  • Allow grout mixture to rest or slake for 10 minutes after mixing, remix and use. Do not add additional water or admixes once the grout is mixed.
  • Thoroughly dampen joints of absorptive, highly porous tile with clean, cool water but leave no standing water in the joints.
  • Allow grout to become firm in the joints. Remove excess grout and smooth joints using a lightly dampened sponge with small, tight pores. Do not use a "wet" sponge or a sponge with large pores. Use as little water as possible in clean-up.
  • Lightly mist the grout installation periodically with clean, cool water for 72 hours.

Remove 1/2 to 3/4 the thickness of the tile.

Yes. However, epoxy is temperature sensitive. 100% Solids Epoxy Grout is easiest to apply when temperatures are between 70° F and 85° F (21° C and 29° C). Lower temperatures will cause the epoxy to become stiff and more difficult to work, and will extend initial set time. Higher temperatures will cause the epoxy to become more fluid and will accelerate the set time. It is not recommended for installations exposed to continuous temperatures above 160° F (71° C). When used on exterior installations, color variations may occur over time, especially with lighter shades.

Grout looses moisture too rapidly when curing in hot and dry weather. When this happens, the grout will not dry hard and may also dry an uneven color. Follow these installation tips:

  • Use a polymer-modified grout, such as Polyblend to retain moisture and promote proper drying conditions.
  • Keep it cool. Use cool water to mix grout powder; never use hot or warm water. Keep ice on hand to cool down the water. Keep the grout bags and mixing container cool.
  • Do not mix the grout with excessive amounts of water or remix with additional water. This will cause a lighter, soft and powdery grout.
  • Avoid midday grouting in extreme heat. Grout in the early morning or late afternoon when temperatures are cooler.
  • Dampen the tile with clean, cool water prior to grouting. This prevents porous tile from drawing the moisture out of the grout too rapidly and helps to cool down the tile.

There are a few reasons why grout may crack. Almost all can be prevented with proper installation. Three of the most common methods to prevent cracking grout are:

  • Do not use a non-sanded grout on joints that are over 1/8" thick. It isn't designed to fill larger joints.
  • Do not set tile directly over a flexible surface like plywood. It tends to distort over time and will cause grout to crack. We recommend the installation of WonderBoard Lite over a plywood subfloor for a reliable and long-lasting installation.
  • When filling grout joints, make sure the joints are completely filled during installation. Solidly pack in the grout. Do not leave any pockets or voids.

SuperiorBilt grout floats offer unique one-piece construction and the exclusive non-slip, SoftGrip™ handle to reduce fatigue. These grout floats are durable, easy to clean and won't mar surfaces.

  • Standard Grout Float - for most standard and non-sanded grout applications
  • Large Grout Float - for greater coverage
  • Offset Grout Float - for hard-to-reach areas
  • Margin Grout Float - for small jobs, repairs or hard-to-reach areas
  • Stone Grout Float - for natural stone and textured surfaces
  • Epoxy Grout Float - for hard-to-spread grout types

Water-based stains such as wine or juice may etch stone surfaces. Oil-based stains such as salad dressing or grease are hard to prevent and hard to remove. All TileLab sealers are effective against both water-based and oil-based stains. Silicone sealers are not typically effective against oil-based stains.

Penetrating sealers act as an invisible barrier to stains by penetrating the surface of grout and porous tile. TileLab's SurfaceGard and Grout Sealer are penetrating sealers that provide a natural look for any unglazed tile or grout.

Finishing sealers provide a protective sealer on top of grout or porous tile to resist stains, dirt and grease. TileLab's Gloss or Matte Sealer & Finish offer these benefits. Surface sealing is not recommended for marble, limestone or granite.

Even if your tile is glazed, the grout can get stained and needs to be sealed. Wait 48-72 hours after installation to seal your tile, then apply SurfaceGard according to directions.

These calcium-based stone types are very porous, which makes leaving them very susceptible to acidic stains. Many food products, such as lemon, wine, tomato sauce and coffee, are acidic. Definitely seal marble and travertine after installation.

TileLab penetrating sealers, such as SurfaceGard®, provide a natural look to not change the appearance of your stone, grout or tile. But to add life back into worn stone or grout, use StoneSpecific™ Stone Enhancer + Sealer, which deepens or enriches the color while protecting against stains inside or out. Be sure to test the results in an inconspicuous area before completely applying.

No sealer can prevent all stains all the time. The sooner any spill can be cleaned up the less likely a stain will result. Acidic spills such as juice, soda or wine can actually etch and dull polished stone if not wiped up promptly. Clean tile and grout regularly so dirt and stains don't have a chance to build up.

You should wait 48 - 72 hours after your installation to seal it. This will ensure that all moisture is removed from the installation so the sealer is not diluted.

Before applying another sealer, use TileLab Heavy-Duty Cleaner & Stripper to remove acrylic or wax finishes. It's concentrated for tough cleaning and is safe for grout, tile or stone.

Many ordinary household cleaners contain harmful abrasives or acids, which will damage stone, grout and porous tile surfaces. TileLab cleaners are specifically formulated to be safe for all stone, grout and tile surfaces. The ideal solution is to use TileLab® Grout & Tile Cleaner & Resealer every day, because it contains a small amount of SurfaceGard to reseal your surface with each use.

Pretty much all of them. However we don't recommend finish coatings (Matte and Gloss Sealer and Finish) on any honed or polished stone such as marble, granite or limestone. They can be used on slate and flagstone.

All TileLab products are safe for food preparation areas.

Mold and mildew growth is a very common occurrence in wet areas, such as tub surrounds and showers, since they require a dark, moist area and a food source to live. The grout itself is naturally resistant to mold and mildew because it is made of cement, which is a hostile environment. However, when a food source such as soap scum is present on a shower wall, it sets up an ideal environment for mold and mildew to grow. The key to preventing this is to seal the grout periodically to prevent soap scum from penetrating the grout surface and make removal much easier. Also, regularly clean it to prevent build-up of soap scum.

You can extend the life of a diamond blade by dressing the blade with a soft abrasive rubbing stone or cinder block. Dressing the blade exposes fresh edges on the diamonds, giving them renewed life.

Here's an installation tool checklist to help you get started:

Backerboard screws
Notch trowel
Tile cutter
Tile spacers
Spacer puller
Grout float
Grout sponge
To make the job easier, use:
Knee pads
Floor scraper
Margin trowel
Tile nippers

A tile installation project typically involves several different types of cuts so be sure you have all the tile cutting tools you need. You may need to make straight cuts, cutouts and holes. Practice making cuts in tile before the job begins. Wet saws are great for precision cuts on stone and tile, particularly large tiles. Tile cutters are excellent for fast, straight cuts. Tile nippers are good for breaking away small pieces for edges that are typically not exposed, like under a toilet. Hole saws work well for cutting circles in tile. A 1-3/8" hole saw works for most plumbing fixtures.

For lengths of:
25' to 50' - at least 12 gauge
50' to 75' - at least 10 gauge
50' to 100' - at least 8 gauge
75' to 100' - at least 6 gauge

Wet cut blades require water, but dry cut blades can be used without water. Wet cut blades should only be used on saws designed to be used with water and have UL or CSA listings. Water acts as a coolant during the cutting operation, provides a smoother cut with less chipping, extends the life of the blade and minimizes dust.

Custom offers diamond tile blades for basic and specialty cutting. Blades vary based on the material being cut and the quality of the blade. ProBiltSeries blades are available for wet and dry cutting of all tile and stone materials.

Yes, but they are synthetic.

No, there are three basic types of diamond blades: continuous rim, segmented rim and turbo. Continuous rim blades can be either wet or dry cut, produce the smoothest of cuts and are made for specific uses like Porcelain. Segmented blades have key slots that act as water gullets to cool the blade. These are best when the speed of cut is important and chipping is acceptable. Segmented blades typically last longer and work well with a variety of materials. Turbo blades have a continuous serrated rim with water gullets for cooling. These work well when a fast cut is not a requirement, some chipping is acceptable, and blade life is not an issue. Turbo blades are excellent with rough cuts and are more versatile than segmented blades.

The size of the notches determines the amount of setting material that is put on the surface. The notch size is determined by the size of the tile you are setting. You should use the proper-sized notch trowel to ensure 100% coverage of solid mortar under tiles. With very irregular tiles, back-buttering may be advisable. For detailed recommendations see our Notch Trowels.

Custom's batch number is an 8-digit code imprinted on the container. It is a way for us to identify when and where the product was made. This code is typically located on the bottom or side of a bag product. Bottle product code numbers are imprinted anywhere along the edge of the bottle.


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