Epoxy Grout or sanded or unsanded for ceramic tile and stone tile?


Epoxy Grout - Is epoxy grout preferable to sanded or unsanded grout for ceramic tile and stone tile on the interior of homes. Please list the advantages and disadvantages.


ANSWER - Epoxy grout has significantly greater bond strength and compression strength over cementitious grouts. It is also very stain resistant.

Sanded grout is meant for grout joints that are 1/8” wide or more. Non-sanded grout is meant for grout joints that are 1/8” wide or less. Most epoxy grout will barely fit in a 1/16” wide joint. Grout joints are meant to be fully filled for maximum performance.

Epoxy grout requires more effort and labor to install than cementitious grout. The epoxy sets up fast and doesn’t have as much adjustability nor as forgiving as a cementitious grout. Installers who are new to installing epoxy grout without a lot of practice tend to struggle with the installation.

Porous stone and unglazed tile or textured tiles need to be protected when grouting with epoxy. The epoxy can stain in some cases and it can be difficult to remove from a textured surface. Using a penetrating type sealer or grout release can provide added protection.

A bad epoxy installation is normally very rough, has irregular joints, and has pin holes.

The epoxy itself maybe stain resistant, but if the surface of the epoxy grout is rough it will tend to pick up dirt easily and be difficult to clean. The surface of the finished epoxy grout should be smooth.

If installed well, epoxy grout can be very beneficial. Good Luck!

8 thoughts on “Epoxy Grout or sanded or unsanded for ceramic tile and stone tile?

    • Donato Pompo says:

      Epoxy grouts don’t come sanded or non-sanded. They do add a fine aggregate to the part A and B resins. The epoxy grouts normally will fit in grout joints less than 1/8″ wide as non-sanded grouts do. All of the major manufacturers of tile installation products offer epoxy grouts.

      A experienced and skilled installer can install the epoxy grout with a very smooth surface, but if not done correctly the epoxy grout can come out very rough.

      • Transsmile says:

        Who are the major manufacturers of UNSANDED epoxy grouts?
        Most epoxy grouts need part c powders which are silica sands, ie SANDED.

        • Donato Pompo says:

          All epoxy grouts for tile installations have a Part C aggregate. Sometimes it is a glass bead or a quartz sand or a cementitious grout. They typically don’t sell it as a sanded or unsanded product. The typically they say that the their one epoxy grout will fit in a tight grout joint less than 1/16″ wide or in a larger grout joint width.

          You need the part C in the epoxy grout to give it body or it will tend to flow and have sunken in grout joints.

  1. Michael Basile says:

    Can Flexcolor sanded grout be topped with a non sanded epoxy grout to create a smooth grout line? I preferred the non sanded but was convinced his choice was better for a 3/16 opening. The rough surface grout line is going to get mold, etc. Thank you.

    • Donato Pompo says:

      Mapei Flexcolor grout is a premixed ready to use grout. Not sure if they are chemically compatible. To apply a thin coat of epoxy to the grout surface would be a very tedious process that could lead to cleanup problems and possibly chipping tile depending on how you apply it.

      The Flexcolor grout is suppose to be impervious and if it contains portland cement then it will be alkaline and resistant to mold. So that should not be a concern. Textured surfaces do tent to pick up dirt more readily and may require more effort in cleaning, but it shouldn’t be a big problem.

      Whether you have a sanded grout or non-sanded grout you still should use a scrub brush on an extended handle during cleaning and use a wet vacuum to pick up the dirty water.

  2. Scott says:

    Bath floor, shower and walls
    My kitchen grout has a very smooth surface that is scrub-able and stain resistant. I was looking for something similar for the shower. Spectra-Loc is very rough and testing shows quite porous as water soaks in. “epoxy smooth if installed correctly”
    How? Any other product advice?

    • Donato Pompo says:

      Spectra-Loc is advertised as being stain resistant. My understanding is that it is not very porous and has similar characteristics to epoxy grout.

      If you have a grout joint that is 1/8″ wide or less you can use a non-sanded grout that is smooth, but more prone to staining.

      Epoxy grouts are the most stain proof, but inexperienced installers can cause the grout to be textured that can be harder to maintain and tends to get dirty sooner. If you know what you are doing you can make an epoxy grout joint very smooth so it is more maintenance free. Of course nothing is self-cleaning.

      Right away after the epoxy grout is forced into the grout joints and the excess is scraped clean off of the tile surface with an epoxy hard rubber grout you have to tool the joint. You should get water with liquid dish cleaner added to it to make it slick. Then with rubber gloves on your hand use your finger to tool the joint to create a smooth slightly concave surface. You have to do soon after applying the epoxy or otherwise it will be difficult to smooth it out.

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