How To Color Grout

This article is about coloring grout for mosaic art before the grout is applied.

This article isn’t about staining grout for bathroom backsplashes. From what I’ve read, staining bathroom grout doesn’t tend to last but has to be refreshed within a year or two. If I wanted to change gout color, I would remove the existing grout with a grout removal tool and then re-grout.

Another problem with grout stains and concrete dyes is that they tend to be limited in color, especially what is available at your local building material store.

Coloring Grout With Acrylic Paint

White grout (for dry indoor mosaic art*) can be colored with artists acrylic paint. You should mix the grout up according to manufacturer instructions, and once you have a nice lump of grout with a consistency similar to dough, you can add the paint. Mix in the paint a little bit at a time until you work up to the color you want. (It’s easier to add than remove, as my father would say.)

Make sure you use white grout because white will be easiest to color. If you find that you can’t get a dark enough color with white grout, then consider starting with grey grout. However, if you start with grey grout, you may find it easier to get a darker color, but it might be less intense than what you got with the white grout.

*Outdoor And Wet Mosaics

I’ve not used this on wet mosaics. That doesn’t mean it cannot be done. It only means you should test first and be aware that not all pigments are UV resistant and can fade with prolonged exposure to sunlight.

Testing For Outdoor Use

I would test my colored grout by placing a hardened lump in water for a week and look for signs of color leaching or softening. I would use a minimal amount of water and look to see if the water was tinted after a week of soaking.

I would also make a few other lumps for hammer hardness testing. I would have a few control lumps with NO paint added so I could compare their hardness to the experimental specimens. Place the head of the hammer in your hand and press down on the sample with increasing weight until it crumbles. The specimens with paint should be more resistant to crumbling. Definitely email me if you observe anything different.

Use Studio Grade Pigments For Reds, Oranges And Yellows.

Use studio-grade or student-grade pigments when it comes to reds, oranges and yellows. The artist-grade pigments of reds, oranges and yellows are cadmium oxides, which are toxic. Studio-grade pigments are generally “non-toxic,” which means there isn’t a known toxic effect in the short term.

Acrylic Paint Strengthens Grout

Acrylic paint should improve the tensile strength and impact resistance of the grout the same way thinset is fortified with polymers. Of course, all of this refers to conventional grout and not the new epoxy-based grouts. I have no idea what could be done with epoxy grouts.

Should You Color Grout?

The most important question about coloring grout is should you color it.

Consider the following:

Novice artists tend to see the choice of grout color as an opportunity to improve their mosaic. Experienced artists tend to see grout color as a potential to screw up their mosaic and thus tend to make a conservative choice for grout color,

Grout color should contrast tile colors not match them. Unless you are using gray tile or light blue tile, a medium gray is usually the best choice of color because it tends to contrast the most colors. If you match grout color to tile color, then your tiles won’t be separated visually, and the mosaic effect will be lost.

The grout line is best used to separate the tiles visually and not as a color field. Think about how a thin pencil line provides definition to watercolor paintings but not color. That is how grout is best used.

Wrong Color Grout?

If you realize that you chose the wrong color grout, I wrote an article on fixing grout mistakes, including wrong colors.

Test Color Of Hardened Grout Before Applying To Mosaic

Of course you should test the color of your mix before applying the grout to your mosaic. By test, I mean mix up a small amount of grout and color it and allow it to harden overnight. You need to know what the grout looks like when it is hardened and dry before you even consider applying it. Keep in mind that grout always looks less intense and lighter after it has hardened.

If you are worrying about wasting a little grout and paint by testing it in this way, then consider how much you will waste if you apply it to your mosaic and it isn’t right…




15 responses to “How To Color Grout”

  1. […] to be creative and artistic. I found this really great article about deciding whether or not to dye your grout and how to with acrylic paint. I’ve never dyed my grout for my mosaic pieces before, but […]

  2. Nico Morris Avatar

    wow like your comments ,and love the background image,Is that in mastic,or just supplies sitting there?
    love to talk more about tech(I have been doing up-cycle and tile mosaic for 30 yrs and worked as a tile setter for 3 years.

    Potter for 47 years

    working with kids now….

    1. Joe Moorman Avatar

      The artifacts are set in thinset mortar and are permanently attached.

  3. Margaretha jordaan Avatar

    I am discovered the satisfaction of mosaic resently, and fell totally in love with it! My question might be out of order regarding this topic but perhaps you could help, I have arthritis in my hands and find the cutting of tiles difficult is there perhaps easier ways to cut tiles to pieces except for using the one tool one buys at art shops!

    1. Joe Moorman Avatar


      I understand completely. I wrote an article explaining how to mount a cutter on the side of a table and use a lever arm so that the cutting does not require much hand strength or grip:
      Of course, you would need a handy friend to set this us for you, but it really does make it a lot easier.
      I hope this helps!

  4. Avril Baker Avatar
    Avril Baker

    really appreciate your wisdom in this article, thanks for your help. I intend to make mosaic tile in my garden instead of laying paving slabs, have you done any like projects and if so any advice you can offer.
    (the grout colors are for a project for children)

    1. Joe Moorman Avatar

      I’m not sure I understand your question. Pavers or stepping stones are a great way to put mosaics in the garden in a way that is scalable and easily modified:
      I hope this helps!

  5. Helene Beadman Avatar

    You answered all my questions that I needed to know. Wow..I feel so much more confident to finish my coffee table. First time ever I do mosaic. I drew two big leaves in terracotta color tiles, framed it with beige tiles, then contour with white tiles marbled in beige around the leaves. Now I will dye the grout a deep chocolate brown for the table top and paint the legs same color as the grout. I can’t thank you enough, your information really helped me and money savings too. It’s so wonderful and kind for people to share their talents. Thank you so much..

  6. michele Avatar

    Great explanation! Can I use this for grouting glass beads to a 3D object?

    1. Joe Moorman Avatar
      Joe Moorman

      Michele, I think you are asking about something else. I use thinset mortar to attach glass, ceramic, and stone objects to concrete surfaces. Here are my tips and instructions for using thinset mortar for mosaic and sculptural art with found objects.

  7. Jeannie Avatar

    Thanks so much! I just finished a sculptural piece and was set to grout it with some great colored grout that I had picked up a while ago, but when I went to mix it, I discovered that the grout had somehow gotten damp and was super lumpy – no longer suitable for use. So I began searching for some new grout in the colors I had planned to use, only to discover that the prices were absolutely exorbitant! I have used pigments in my grouts in the past, but not paint, as I intend to do now. Thanks again for the info!

  8. Fabrizia Avatar

    Can I use acrylic pigment mixed with grout for a plunge pool mosaic? I will definitely coating with a sealer before filling up by water!

    1. Joe Moorman Avatar
      Joe Moorman

      No, you should concrete pigments for dyeing grout for pools and other architectural installations.

  9. Laura Avatar

    Hi there, i am using upcycled tile for a mosaic and use a wheeled tile cutter. Im finding that the tiles are not cutting cleanly, and are chipping. Am I not using them correctly, is it the tiles, or should I use another type of cutter?

    1. Joe Moorman Avatar
      Joe Moorman

      It sounds like the type of glass might be the problem, but you might need to replace the blades. I recommend testing the cutter on standard types of mosaic glass.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.