Giant Mosaic Mural:Return of the Grout

It is finished. My giant, lovely mosiac mural is installed and hasn't fallen off the wall, yet.  Fabulous.

created on: 02/26/08

So where were we with the last couple of posts?

Well, we'd come up with a design, collected and then broken up the plates and tiles, glued them down, and let them set.


Always my least favorite step in the mosaic making process. And, the one that always has to come last, so you can't get mad at me for leaving the dirty work until the end.

Grouting IS optional, but, it really unifies the piece. I wouldn't recommend skipping it with something this large, with edges this irregular. But if you were making, let's say, a planter or stepping stone, you could embed the mosaic pieces into the concrete instead of adhereing to a backer board, and then having to grout around it.

Anyway. I decided to use white grout for the cups and black grout for the background, to make the background receed and the foreground (coffee cups) come forward. I grouted the cups first, then did the background.

I used sanded grout for this mural, because the gaps were larger than recommended for the non-sanded kind. You simply mix the stuff up with water in a bucket, I look for a consistency of 'malted milkshake', that seems to work best.

created on: 02/26/08

Note the gloves? This stuff will DYE YOUR HANDS BLACK so wear rubber dishwashing or gardening gloves when working with the colored grout, or you will regret it.

Once the water's all mixed in, and you're happy with the consistency, you splash some on the surface using your mixing stick or hands. Rub it into the cracks with a sponge-there's a special kind that's got an extra rough surface on one side.


created on: 02/26/08
created on: 02/26/08

See how the sponge is dyed black too? That's what will happen to any clothes you're wearing. Ack! Be careful!

Once you've pushed as much grout as you can into the spaces between the tiles, let it sit for a few minutes. Then use the sponge to wipe off the tiles. You're going to do this several times. I didn't use water at ALL during this step, but some people swear by it. The key is to rub the grout OFF the tiles, and INTO the cracks.

You can also use old rags for this step. It's gonna get messy, and little bits of sand and grout are gonna fly around. So keep a shop vac near by for this part.

created on: 02/26/08

Keep rubbing until the surface tiles are almost totally clean-then switch to a clean rag or towel to give the final buff. Let it sit for a day or two, and re-buff if needed.  Grouting the entire mosaic took me only about 3 hours, but I didn't protect my hands and fingers well to start with and I ended up slicing open a few of my fingertips pretty good. Please, be sure to wear gloves ALL the time, and keep your tools (HANDS) protected!!


My Dad and I packed up his SUV with the panels, with a layer of cardboard between each one for extra protection. We drove them down, during a crazy snowstorm, to the construction site.


created on: 02/26/08

When I got to the site, the guys had already finished off the wall with Plywood instead of Drywall. Since the panels weighed about 45-60lbs each, this was just a precaution. If you were installing on drywall, you could use anchors instead of 2.5 inch screws like we did.

They were insistent that the edges be square, so they used a grinder wheel to get the extra bits of grout, adhesive, and stray tiles shaved down. (WEAR EYE PROTECTION!!!!!)  They were also worried about the warping that had occured to the boards, so we decided to scatter screws around the piece to make sure the center of each board wouldn't bow out.

We put up a 'cleat' to make sure they were being installed level, and threw some liquid nails on the back as well.

created on: 02/26/08
created on: 02/26/08

Two screws in each corner, and a few scattered around in wider gaps to make the center parts 'stick' to the wall, and that was it!

created on: 02/26/08

After the install was complete, I used adhesive to fill over the screws, and then came back a few days later to grout the join lines.

created on: 02/26/08

See the white outline tiles in each corner of each panel, along the middle and top and bottom? Those are the 'new tiles'.

So the guys put up some painted 1x6's to act as a frame, and a grouting guide, and I came back and mixed up some grout in a water bottle to finish it off. Same process as before, except now I was working on a vertical surface, so I had to put down some construction plastic on the floor to catch the dropping blobs of grout, and blue painter's tape on the frame to keep the black grout off of it. I also threw some grout over the screws that were really visible-but since they were black screws in black grout, they mostly disappear.

I bought some white pre-mixed grout that was actually adhesive AND grout, and I wasn't at all happy with that product. I wouldn't recommend it, it was way too glue-y for me and it stuck to the tile surfaces more than the other sanded grout. Ish.


created on: 02/26/08

All done!

The guys recommended that if I ever do this again (and I hope to!) that I could get away with using a much lighter weight (and cheaper) cement backer board, because this will never actually come in contact with water. I was using Durock because that was what was recommended to me, and apart from its size, weight, and horrible fumes while cutting, it wasn't actually that bad to use.  They also recommended I make a box out of 1x6's to keep the edges 'clean' to begin with, so I won't have to grind the edges down for the next one.

If anyone wants to tackle a project like this, I hope it's been inspirational. It's by far the largest-scale mosaic mural I had ever attempted, and I learned a lot of really valuable techniques by reading everything I could at the book store-then trying it out-and seeing what worked for me!

Visit it at the new Dunn Brothers' Coffee Shop on Washington at Cedar in Minneapolis. It's directly across from the Alumni Center, and adjacent to an Erbert's and Gerbert's sub shop.


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DesigningMom on Mar 05, 2008:

Wow What an amazing task. I love it! Great job!

~ Becky <><

ModHomeEcTeacher on Feb 27, 2008:

That is SOOOO unbelievably beautiful.  Can you imagine (or do you know) how much that must weigh?

Soo..is this your new art form?  Very talented, you are.

beccajo on Feb 27, 2008:

actually, my folks have offered to make me a plaque for the wall (awww!). since i made it, i have seen folks who use a piece of clear glass like a slide mount or piece of stained glass as a cover for a hand-written or typed message. in the future, i'd probably go that route.

cassandraj on Feb 27, 2008:

That is fabulous!

bruno on Feb 26, 2008:

Congratulations! It looks great! I'll have to stop by and check it out in person. One question: did you sign it anywhere?

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