Wednesday, March 17, 2010

Sanded Grout vs. Non-Sanded Grout

In my last post I mentioned ordering non-sanded grout from Home Depot in specialized colors, and I have had a couple of people ask me why I would choose non-sanded over sanded. I have used both (and will in the future), but I prefer the look of unsanded grout, and I prefer working with it as well. I know a lot of artists hate it – I have heard it called “the devil’s toothpaste” before – but I find it easier to work with than the sanded. I’ll get into some of the reasons why in a minute. I think it’s largely a matter of personal preference, but there are some guidelines worth noting.
Non-sanded grout is intended for interstices (spaces) between tesserae of 1/8” or less. That’s a pretty hard and fast 003croprule. It says so right on the box. If your work is such that the spaces between tiles will be larger than 1/8”, use the sanded. This is common when using lots of odd shaped tiles, found objects, or glass gems. The unusual shape will sometimes dictate the spaces between tess. An example of tesserae dictating the choice of grout is my Mexican style dragon I recently completed. I used imported Talavera tile. This tile is a red body clay that has a glaze over it. It will rarely break cleanly. Most of the time there is a sloped edge, where the clay undeerneath extends out further than the glaze. This will prevent you from placing the tess (or at least the glazed parts) as close together as 1/8” . Also, notice in the detail photo the space between the metal ball chain and the surrounding tile.

On the other hand, I usually use glass which breaks much more cleanly, and can be placed much closer. In this detail photo of Delta Blues, you can see the tight spaces between the tess. Although those are much smaller interstices, it would be possible to use sanded grout in them, but I chose unsanded for the smooth look.
So – why would I like working with “the devil’s toothpaste” more than sanded grout? I’ll tell you my experiences with both, but understand this isn’t anything scientific, and others will have had different experiences.
Those who have used thinset as an adhesive will know that you can keep it workable for an extended time by stirring it frequently. It’s the same principle as a cement mixer – by keeping it moving, you prevent it from curing. I have found that I can do the same thing with non-sanded grout, and to a lesser extent, the sanded grout. In my experience, sanded grout begins to feel dry and crumbly faster, even with frequent stirring. Once it begins to get dry and crumbly, it won’t stay in the interstices well – cleaning off the excess removes a lot of what you hoped to keep. It also gives you a bit less time to go back and clean it off before it sets, which then makes the clean up a lot more difficult. Non-sanded grout does have a somewhat “plasticy” feel. But I find that the smoothness of it makes it easier to wipe off the surfaces of the tess, reducing cleanup time, and it seems to leave behind less of a grout haze that has to be polished off once it’s completely dry. With the longer working time, smooth look and easier cleanup, I will choose non-sanded whenever circumstances permit!


  1. Thanks for this Lee Ann - its a great post as it sets out experience of both types so well. ;)

  2. This is a very interesting perspective Lee Ann. I definitely fall into the category of sanded grout fan but I may have to try unsanded again one of these days. I tried unsanded grout when I first started mosaicing and was so turned off by the texture that I never tried it again. And even though sanded is not the recommended choice for groutlines under 1/8-inch I have never had a problem so I've always used sanded grout for all of my projects.

  3. Thanks so much for sharing your experience and perspective! I'm still very new to this mosaic thing and am experimenting like mad; I think I will try nonsanded grout at some point because sometimes the sanded grout makes me nuts. Using nonsanded for glass pieces makes a lot of sense. One more question: do you spread the nonsanded over the piece with a sponge (I do that with sanded) or use another method? Again, thanks!

  4. Glad you found this helpful. And Josh, you're right about being able to use the sanded in amazingly small spaces - I wonder if it isn't recommended for groutlines under 1/8" just so they can sell you another product! lol. @Anna - I spread the grout on with what is called The Mud Tool, and remove the majority of it with The Grout Elf. Here's a link so you can see what I'm talking about Then I finish wiping off the excess with paper towels. I clean it off while it is still rather wet.



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