Need to know quick! Sanded vs unsanded grout - what to use?

elizpizOctober 1, 2008

Hi all - I may get responses too late to make a difference, but in the interest of others who might need to know - what's the difference between sanded vs unsanded grout? Our floors are being grouted today and our GC tells us that we should get sanded grout. The place where we bought our floor tiles (which are honed limestone), suggested unsanded. GC says that because the floors are heated, sanded is best (stronger) and that he never uses unsanded.

What's the difference and more importantly what's the difference in the end result (look?).



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I've learned from this forum (thank bill v.!) that unsanded grout is used for narrow grout lines like 1/16 and sanded for larger. I don't know how the fact that the stone is limestone factors in. Is it honed and filled? Hopefully, Bill or another expert will chime in.

    Bookmark   October 1, 2008 at 7:55AM
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Hopefully Bill or some of the other experts will see this. I am not an expert, but I do know that sanded is much stronger and hold up better. I think it is intended for 1/8" or wider grout lines. For teeny grout lines, you have no choice but to use unsanded.

    Bookmark   October 1, 2008 at 7:57AM
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Thanks so much for the quick responses - I love this forum!


    Bookmark   October 1, 2008 at 8:19AM
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Hi Eliz:

Post your question in the John Bridge tile forum. They are a HUGE help when it comes to all types of tiling questions. They were great help when we were doing our backsplash project. Good Luck!

Here is a link that might be useful: John Bridge tile forum

    Bookmark   October 1, 2008 at 2:11PM
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There's a difference in look because sanded grout has, surprise, sand in it that is visible. The texture is rougher and gives more dimension. Unsanded is pretty smooth and probably better used where the grout lines are thin.

As for strength, I'm a bit puzzled just because grout isn't going to add strength of any sort either way. The tiles better be set well in mortar to stand up. The grout is just to seal the gaps. If it cracks it's because there's movement in the tiles or subfloor, which is a problem with that, not the grout.

    Bookmark   October 1, 2008 at 4:58PM
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I'm curious about this as well. Eliz, please post your findings, thanks!

    Bookmark   October 1, 2008 at 5:01PM
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Non sanded grout for 1/8'' & smaller grout lines. Sanded for larger. Sanded grout is stronger and there's less shrinkage w/ sanded grout. (That's because the sand doesn't absorb any water that will then evaporate and shrink the grout.)

    Bookmark   October 1, 2008 at 6:00PM
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Thanks all. GC ended up using sanded (grout lines are 1/8") and the floor looks great. Will post pics in the next day or so when it's cleaned up.


    Bookmark   October 1, 2008 at 7:27PM
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but I do know that sanded is much stronger and hold up better. I think it is intended for 1/8" or wider grout lines.

It's not that it's stronger. It's that it doesn't shrink as much, because of the fact that most of its bulk is the sand.

As for the explanation of the different grouts, I just posted this in an FAQ thread on the gallery side of the bathrooms forum. Here it is, copied and pasted:

Although there are others, for all intents and purposes, there are two kinds of grout-- portland cement based, and epoxy. The portland cement based grouts are the conventional grouts that have been around for millenniums. Although in the last few decades, they've been modified with latex and other polymers to make them stronger and more resistant to mold and mildew, they're basically the very same grouts that have been used since Greek and Roman days. There are two kinds of portland cement based grouts. One is sanded, and the other unsanded. The only difference between the two is, as their names imply, the sand. The ONLY thing that determines which grout should be used is the joint size. NOT the glaze, NOT aesthetics, NOT the material (ceramic vs. glass or polished marble), NONE of those. I'll repeat-- the ONLY thing that determines which is used, is the joint size. Anything under an 1/8" takes unsanded grout. Anything 1/8" or bigger, you use sanded grout. If you use unsanded grout in larger joints, the cement in the grout will shrink way too much as the water evaporates out of it, and the joints will end up shrinking and cracking bigtime. If you try using sanded grout in smaller joints, the grains of sand will literally clog the top of the joint, and not allow the grout to get down INTO the joint, and the grout will flake off in a matter of days.

As for the Epoxy, most epoxy grouts use a much finer "sand", and therefore can be used in any size grout joint. Further, epoxy grouts are everything people say they are. They're much easier to clean, practically stainproof, and also extremely expensive. Most epoxies will cost atleast 4 times the cost of conventional grouts, and the installer will also usually charge a premium of between 1.50- 2.50 a foot for the use of epoxy grout. There are alot of people who will disagree with me, but my own opinion is that for most residential installations, epoxy grout is bigtime overkill. The ONLY times I'll recommend epoxy grout is first, if you're installing a tile countertop, and two, if you have animals in the house that either aren't housebroken, or are prone to accidents. In either of those cases, epoxy might be worth the money. For anything else, though, conventional grout is more than good enough.

    Bookmark   October 1, 2008 at 9:44PM
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Great description Bill! Interesting that our grout lines for the backsplash will fall at the 1/8th mark like Elizpiz. Bill, you mention 1/8" or bigger use sanded. I noticed Cilantro mentioned 1/8" or smaller use unsanded. Our GC recommended unsanded. What do you recommend at exactly the 1/8 mark?

    Bookmark   October 1, 2008 at 10:12PM
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I'm guessing you'll say 1/8" should go with sanded...your instructions were very clear above. (Please don't yell!) Just want to double check. =)

    Bookmark   October 1, 2008 at 10:14PM
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We have large grout lines (about 1/4") on our shower floors and our installer used unsanded grout. Of course, it's cracking (and it's only been about 2 months). How should we fix this? Regrout sanded over the existing cracks? Or do we have to remove all of the unsanded grout and have the whole thing regrouted?

Thank you!

    Bookmark   May 25, 2009 at 2:10PM
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Hi Keri,

Sorry to hear about your installer not choosing the appropriate grout for your shower. Unfortunately, my recommendation would be to remove the unsanded grout before you re-grout with the correct sanded grout. The reason is more then likely there is not enough area that the sanded grout will stay in the joints properly. There needs to be at least 1/8 inch layer of new grout in the space to stay put and not flake or crack. It would be helpful to use an acrylic mortar admix liquid to the sanded grout which will make it adhere better.

Good luck!

This post was edited by TileExcellence on Sun, Jan 19, 14 at 22:11

    Bookmark   January 19, 2014 at 10:06PM
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