Staining Grout with Acrylic Paint

Staining Grout With Acrylic Paint

Mosaicists sometimes mix in artist acrylic paint to create custom colors from white grout, but you can also use acrylic paint to “stain” grout after it has hardened (for dry indoor mosaics).

Like the process of staining wood, “staining” grout with paint is a process of wiping on and wiping off. The paint sticks to the rough grout but wipes off the glass tile.

The reason I say “stain” in quotes is that even though the grout is porous and there should be some penetration like a wood stain penetrates wood, there should still be a surface coating of paint over the grains of sand. Note that if you wipe the paint off too aggressively, the light grains of sand at the surface will be exposed.

TIP: Wipe the paint on and off relatively quickly so that it doesn’t have time to harden on the glass tile. Acrylic paint dries very quickly. If you do have some paint dry on the tile, you can take it off with a ScotchBrite pad.

Recently employee-artist Angela Bortone made a mosaic Christmas ornament from one of our hard polystyrene kits, and she used a light gray grout with white tile, and so the grout didn’t provide enough contrast.

Mosaic Christmas Ornament Light Grout
Mosaic Christmas Ornament with Light Grout. Notice how the grout provides enough contrast for individual tiles to be visually distinct but not enough contrast to add visual interest.

Angela used this problem as an opportunity to try out staining the light grout with black paint so that there would be maximum contrast with the white tile.





29 responses to “Staining Grout With Acrylic Paint”

  1. mymysticmosaics Avatar

    some tiles, while beautiful, are not flat. What do you do when grout get into the nooks and crannies of your tile?

    1. Joe Moorman Avatar
      Joe Moorman

      I don’t mind grout in the occasional pit or crack because I am trying to make something that looks old and weathered. People who want to remove all residue use brushes and dental picks.

      1. Katherine Rosenthal Avatar
        Katherine Rosenthal

        Thanks, Joe for replying to my question. I really like your advise.

      2. Debi Avatar

        I have been using acrylic paint to change grout color for years, but I didn’t know I could go back and “stain” the grout after it hardened. Thanks so much for posting this today. When I go to my shop tomorrow, I have 3 pieces to stain that have been collecting dust because I wasn’t happy with the finished look.
        I’m going to pay more attention to your tips from now on.

        1. Ruth Gee Avatar
          Ruth Gee

          Excited to learn this too! I have orange fish scales on a grey back ground so will try making the whole fish orange!

    2. Jean Gris Avatar

      You need to wipe /toothbrush / rinse it out (sparingly) when the grout is wet – work as you go. That way you won’t be damaging your tile as you remove the grout in the tile surface. Change/clean your cloth/tools frequently when you do this, or you’ll be ‘sanding’ your tile surface with the grout debris that you have just extracted: this dullens the ceramic surface.

  2. Verdette K. Bagley Avatar
    Verdette K. Bagley

    When mixing acrylic paint with grout for a specific color what is the ration?

    1. Joe Moorman Avatar
      Joe Moorman


      There is no specific ratio. You simply mix in the acrylic paint until you get the intensity of color that you want. I don’t think it is possible to add so much paint that it will not harden (because acrylic paint will harden on its own), but you can add so much paint that the grout looks more like plastic than concrete.

      I hope this helps!

  3. Anne Saphore Avatar
    Anne Saphore

    My indoor mosaic grout dried too light and i was advised that I could darken it by using a wash (water mixed with acrylic paint) of a darker colour. Will this work and is there a ratio of water and paint I xhoukd follow.

    1. Joe Moorman Avatar
      Joe Moorman


      I would use only minimal water applied by misting as needed instead of mixing water in with the paint. The paint should stick to the porous grout but wipe off the glass tile, but you have to get it wiped off before it dries. That is why the misting water bottle comes in handy. If you do decide to mix in some water, use only about 5% to 10% tops. I hope helps.

  4. Ali Baker Avatar

    When I am mixing my sanded grout and acrylic paint, is it possible to add a bit of glitter ?
    Thank You, Joe

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Ali,

      I don’t see any reason you couldn’t, other than the alkali grout might change the color of the glitter. You could test it by mixing up a teaspoon of grout and letting it harden with glitter in it. I don’t think that would be an issue, but I’m fairly sure the glitter wouldn’t be UV resistant and would fade in sunlight.

    2. Terri Hall Avatar
      Terri Hall

      Hi there! Yes the chemical combination of grout can change the color of glitter. I learned this the hard way. My pink glitter turned a horrid shade of green. There are special grout glitters which I have not tried and special art glitters which are said to not change colors. I am searching as well. Good luck!

      1. Joe Moorman Avatar
        Joe Moorman


        Thanks for sharing that valuable tip.

        My opinion of grout as a source of visual interest is that it isn’t the best source of bling. I prefer to get sparkle, colors, and effects from the tile.


        1. Terri Avatar

          Yes. I feel the same way. But I have a certain project that requires a glow between some of the tiles.I am now playing with some mica powders. They are pretty awesome!

          1. Jean Gris Avatar

            I’d love to see this 🙂

          2. Julie Avatar

            How did your mica powder experiment go? I’m pondering the same question, and was considering using a clear glaze of some type to paint on the mica powder. Any advice?

  5. Christopher Malone Avatar
    Christopher Malone

    Will the acrylic mixed grout holdup if it’s put outside?

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Christopher,

      I’ve not tested it, but acrylic is resistant to UV degradation, and so it should make the grout even more durable. Of course, there is also the issue of the pigmentation. Student-grade yellows and reds would probably fade. Umbers and Siennas and Iron Oxides should be fine.

      I hope this helps. Please email us pictures of your project. We love to see what people are up to, and we sometimes can make recommendations from a photo.


    2. isabel margolin Avatar
      isabel margolin

      Hi Joe,
      I believe that some grout comes with shiny flakes. I used this grout way back when, and I can’t recall if I liked the overall look or if it gradually faded.

  6. Colleen Lindsay Avatar
    Colleen Lindsay

    Thank you. This was very helpful. I just grouted a piece and thought.–“Oh great, I’ve ruined it.” Because the grout had no contrast. Gonna work to fix that as soon as my grout dries.

  7. Ray Avatar

    I cover my mosaic with acrylic paint, wait until it is just dry, then rub it off the tile leaving a stained grout (thinset). I the give it three coats of thinned Weldbond (3 to 1) and a couple coats of clear coat. Any opinions?

    1. Joe Moorman Avatar
      Joe Moorman

      No, the paint is wiped off while it is still wet.

  8. dalia rosenberg Avatar
    dalia rosenberg

    How can I maintain a surface coat on the grout when I wipe the paint off the tile? My grout lines are larger than the lines on the Christmas ornament, and the tesserae are too small to be masked off. I end up exposing grains of sand. I used a Benjamin Moore wall paint. Not sure if additional coats of paint will help, or if I should switch to artist acrylic paint. Any suggestions? Thanks very much.

    1. Joe Moorman Avatar
      Joe Moorman

      I don’t think this would work with latex paint. Acrylic dries much faster.

  9. Susan Avatar

    I prefer un-sanded grout because it gives it a much smoother finish. Will this technique work on that type of grout?

    1. Joe Moorman Avatar
      Joe Moorman

      It should work even better than it goes with sanded grout.

  10. chandra Khan Avatar
    chandra Khan

    Can I paint the grout lines on a mosaiced outdoor tabletop which will be covered by glass, please? The existing grout is too light.
    Also the tesserae are unglazed white, beige, pastel green and pink and some black. I thought a terracotta would work but seems too pink. Any ideas what colour might work please?

    1. Joe Moorman Avatar
      Joe Moorman

      You couldn’t paint it easily without covering the porous unglazed tile.

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