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.

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.

 

6 thoughts on “Sanded vs Non-sanded Grout

  1. 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.

    Reply
  2. baselle

    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.

    Reply
    1. Joe Moorman Post author

      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.

      Reply
  3. 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,
    and
    ● 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.

    Reply
    1. Joe Moorman Post author

      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.

      Reply

Leave a Reply

Your email address will not be published.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

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>