Sanded vs Non-sanded Grout

Sanded grout is recommended for grout gaps larger than 1/8 inch, but we recommend it for all grout gaps larger than a hairline simply because so many customers report problems when using non-sanded grout.

Problems With Non-sanded Grout

Some of the problems typically encountered with non-sanded grout include shrinking, cracking and crumbling. Customers often report a crack running down the center of the grout gap or the grout pulling away from one tile or the other. This may be partly due to the novice mixing in too much water or allowing the grout to dry out as it cured (such as can happen with excess heat/AC), but we noticed over the years that all reports of this nature were from customers using non-sanded grout.

Why Sand?

Sand is added to grout to give it tensile strength and toughness (impact resistance) just as gravel is added to concrete for the same reasons, so you should expect an unsanded product to be inherently weaker.

Will Sand Scratch My Tile?

Glass and Ceramic Tile

Sand will not scratch most glass or ceramic tile using normal installation methods. I’ve not ever experienced a problem with sand scratching glass or ceramic tile, and I suspect that cases where people report a problem are due to abuse conditions such as workmen walking across a tiled floor during or after grouting. Normal wiping with a damp sponge or rag should not provide  nearly enough force to scratch most glass and ceramic. However, if your tile has a particularly high gloss finish, then you may want to test it by rubbing a little dry grout or sand on a loose test tile before making your decision.

Sanded grout used on stained glass mosaic art
This mosaic is composed entirely of stained glass, which is notorious for being fragile. Even so, the sanded grout that was used did not scuff up the glass.

Polished Stone Tile and Marble Mosaic

Depending on the type of stone, polished marble tile can sometimes be significantly softer than the quartz sand used in grout, and it IS possible for sanded grout to scratch these materials.

Tumbled Stone Tile

Of course, stone with a natural or tumbled finish should not be capable of being scratched in any way that is noticeable, but here the issue is not scratching but staining. Unpolished stone is porous and can be stained by grout, and so you should always wipe the faces of the mounted tiles with a tile and grout sealer before grouting. Make sure you apply several coats according to instructions and thoroughly wipe away any excess and allow to fully dry before grouting.

Clarification About Epoxy Grouts

All of the grout advice on our websites refers to conventional grout (unless specified) and not the new epoxy-based grouts. The epoxy-based grouts may be recommended for the bathroom due to their enhanced water resistance and durability, but this can be accomplished by sealing a regular grout with a pore sealer. There is no reason to use epoxy grouts for most mosaic artwork, and there are reasons to avoid them. Epoxy grouts are significantly more expensive than conventional grouts, and I suspect clean up is not as simple as it is with conventional grout, which is messy enough as it is.







20 responses to “Sanded vs Non-sanded Grout”

  1. Deborah K from Clarkesville Avatar
    Deborah K from Clarkesville

    Dear Joe, Thank you so much for all of the valuable information you have shared on your blog. Just reading a few subjects has taught me so much and answered many questions that have been festering in my mind. I am very appreciative of your willingness to share.

  2. Pat Schue Avatar
    Pat Schue

    Love the small bits of important information.

  3. baselle Avatar

    Thank you very much for the nitty gritty information. Far too many books say the same things that sometimes do not work and you can tell it isn’t going to work so one wonders whether or not the author does mosaics. Everybody is different and you really have to develop “hands” for tasks. And there are so many different tasks in mosaics!

    I’ve been really “lucky” with unsanded grout. I do definitely mix it so that the consistency is firmer than “creamy”. I carefully grout … I’m not a confident grouter by any means … I take my time. The one step I do not use that every book describes is the dry damp wipe with the grout sponge. Too much water! I do a lot scraping with a rubber edge (one of those 2$ jobbies), then I wait for about 45 minutes and carefully wipe with rags. Then I spritz a towel, wrap the piece in it, and wrap that in a kitchen garbage bag, and I store that in a 60F room. Then I don’t even look at it for a week.

    And finally none of my pieces are all that big which really helps.

    1. Joe Moorman Avatar

      The points you mention should help grout cure much harder than if it is allowed to dry out or if it is contaminated by water from an over damp rag. However, I have had to break up cement products of all types in my workshop for disposal reasons, and I have done some intentional destructive testing, and I can say definitively that a traditional portland cement product (such as grout) can only be so strong without an aggregate of some sort such as sand. The reason is that cement per se has excellent compressive strength but extremely poor tensile strength. Even if optimally cured, a portland cement product without sand is drastically weaker than it would have been sanded. This is a textbook example of materials properties often discussed in engineering schools.

      One of the problems I have noticed in all the online discussions of sanded versus unsanded grout is that hardly anyone specifies whether or not they are talking about traditional grout (portland cement) or one of the new epoxy-based products. I’m thinking many of the people taking part in these discussions might have one of the newer products and not realize it, although I don’t think that is true in Baselle’s case.

    2. Barbara Avatar

      Could you clarify what the “rubber edge $2 jobbie” is? Thank you so much!

      1. Joe Moorman Avatar
        Joe Moorman

        I suppose someone was referring to a cheap plastic grout spreader from the building material store.

  4. Paula Angel-Nielsen Avatar
    Paula Angel-Nielsen

    I just “discovered” this site and find it to be very informative and reader friendly. You cover just about every topic a mosaic DIYer could possibly need, that is, except for one. I’ve yet to be able to find someone who can answer a few questions about sanded grout:
    ● What kind of sand is used to make sanded grout,
    ● Is it possible to make sanded grout myself?
    I’m a senior on a fixed income and can’t afford to buy large quantities of grouts and glues and have trouble finding sanded grout. I’d like to be able to make my own if possible. I have a bag of sand used to weigh down and outdoor bird bath, however, I doubt very seriously that it’s the kind used in grout and even if it was, I wouldn’t know the equation for mixing it. I’ve even asked people in craft stores and they look at me like I’m from another planet! Even books don’t cover this subject. Can you help me?
    Thanks in advance.

    1. Joe Moorman Avatar

      Thanks Paula!
      You need ordinary sand that has been rinsed to remove dirt.
      Sanded grout is sold cheaply in large bags at building material stores.
      Unsanded grout is only used for sealing hairline cracks (or mixing with sand).
      Never buy at a craft store what can be bought cheaply at a building material store.

  5. Felicia Macheske Avatar
    Felicia Macheske

    Hi Joe

    I am curious. Do you find that sanded grout leaves stained glass tesserae cleaner and brighter? I have been playing with grouting tests of various colors and brands of unsanded grout and have found that the lighter colored tesserae (tans and pale pinks and pale yellows) seem dull and gray once grouted and it seems hard to clean off. I am convinced after reading your page and doing some other research that I need to play with sanded grout instead, but I am curious if this is something you any insight on. I hope to achieve a clarity of color of the tesserae that I am not seeing with my samples right now.

    Thanks for your help.


    1. Joe Moorman Avatar


      I don’t think sanded vs. non-sanded makes a difference (if both are traditional portland cement products). I think the issue is that you have some grout residue left on the glass. An old toothbrush and some water could be used to clean this off. Sometimes a little vinegar can help, but you have to rinse it off fairly quickly because it dissolves the calcium carbonate of the grout and can damage your grout lines.

      I hope this helps,

  6. GarrettA Avatar

    great…great… and great. thanks for the gritty info.

  7. Gabriela Hirt Avatar
    Gabriela Hirt

    Thank you for the information. I have done a mosaic on an outside wall (4feet by 18″) and am wondering if there is anything I have to pay attention to in terms of grouting (I was going to use sanded grout) for outside. I live in Victoria, BC, were frost is not so much an issue, but wetness is – lots and lots of rain here. Do you have some advice?

    1. Joe Moorman Avatar
      Joe Moorman

      Whenever you live in extreme climate (rain or heat or cold), you should always find out what contractors are using in your area. The easiest way to to do that is to go to a building material store and talk to the people working there and the customers. Often you can ask people who tile everyday (IN YOUR AREA) why they are buying a particular brand. This is particularly important for sealers and paints and adhesives and that sort of thing.

      You should definitely seal the finished grouted mosaic with multiple applications of a tile and grout sealer.

      1. Gabriela Avatar

        Thanks, Joe. That is very helpful. Will do.

  8. Lisa Valdez Avatar
    Lisa Valdez

    Hi Joe,
    We’re working on an 9 ft. high by 20 ft wide wall using 1/4 inch broken mirror pieces (i.e., mirrored glass). It has an artistic design to it in the middle of the wall, consisting of medium (2 to 5 inches) to some very tiny pieces in that portion, and then larger pieces all around the design (some up to 1 ft in size) all the way to the 4 perimeters of the wall. All the pieces have been attached with contact cement glue. I’ve been trying to find info online on whether it’s ok to use sanded grout specifically on mirrored glass pieces or not. Only found info on grouting glass tiles. We want it to hold strongly with tensile as it is on an entire wall, but not sure if sanded grout will scratch the face of the mirrored glass. If sanded is ok, is there a specific sand grain size or anything that we should purchase? Thanks much!

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Lisa,

      Clear glass such as mirrors are made from is fairly soft, and grout can scratch it. However, a few scratches are better than unsanded grout that with crack and crumble if the gaps are any size at all. You could investigate one of the new epoxy based grouts at the building material store.

      I hope this helps,

  9. Virginia Avatar

    I just had my shower tiled he used unsanded grout
    Will that be a problem down the road

    1. Joe Moorman Avatar
      Joe Moorman

      Not sure. Was it traditional grout or one of the new epoxy or acrylic grouts? Those newer materials might not have sand. We only use traditional grouts and thinset mortars.

  10. Dana Carnazzo Avatar

    Hello Friends, Of course for my first mosaic I am making a 2’x5′ wall piece with glass tile, cut glass annnd some found objects such as Anazazi pottery and sea urchin spines and tiny polished cowry shells….I’m ready for grout. Is there something I should coat the porous pieces with so that I can get the grout off of them when I do that? Also, I went from sanded tile cement to poly urethane glue when it seemed like the tile cement was too bulky under the little glass pieces. At first I used a little too much glue and it bubbled up around the tile…I’d have to use a dremel to cut it back…I don’t mind the look of it, and hope that enough grout will stick so that it looks uniform. I am obsessed and soon my house will look like the Watts Towers!

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Dana,

      In my experience, soft porous artifacts such as unglazed pottery and shells cannot be grouted, at least not in the traditional wipe on/wipe off method.

      The bottom of this page about thinset explains how I used a modified grouting bag and palette knife to carefully apply grout between artifacts:

      Here are our mosaic tools.

      I hope this helps.

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