There are three basic types of grout available for your tile installation. They are:

  • Non-Sanded (also known as Unsanded)
  • Sanded
  • Epoxy

Choosing the correct grout for your particular installation will not only complete the job correctly, it will also cut down on maintenance. Properly installed and sealed grout will last for the life of your tile. So which to use and when?

Non-Sanded (or Unsanded) Grout

Unsanded grout is made specifically for grout lines smaller than 1/8 inch wide.  This is a general rule. I use unsanded grout only in tile with grout lines smaller than 1/16″. Unsanded grout (all grout to different degrees) will shrink as it cures. The reason for only using it in smaller grout lines is the wider the grout lines, the more grout must be used to fill them. The more grout you have, the more it will shrink. If you try to fill grout lines that are too large the grout will shrink enough to pull away from the sides of the tile.

Unsanded grout is easier to work with, especially on vertical surfaces such as a shower wall, because  it is “stickier” than the sanded variety. You can spread it onto the wall and it will stick there while you force it into the grout lines. It is also much easier on the hands than sanded.  Although it is easier to work with, you need to make sure that the application for which you are using it is correct.

Sanded Grout

Sanded Grout is used for any size grout lines 1/8″ and wider. Although the specifications state unsanded grout be used in grout lines that are exactly 1/8″, you really should use sanded for them. It will ensure proper adhesion to your tile and guard against too much shrinkage. No, not Seinfeld shrinkage, grout shrinkage.

Sanded grout has fine sand added to it. This prevents the grout from shrinking too much as it cures. That’s why it is used for larger grout lines and should be used for the majority of tile installations.

If you have a polished stone such as granite, marble, limestone, and some polished travertine, you should be careful about using sanded grout. While sanded may be the correct choice for the size of grout lines, it may not be the best choice. Depending upon the polish of the stone the sand in the grout may actually scratch it. If you decide to use sanded make sure you test it in an inconspicuous area first to ensure it will not scratch your finish. Or use epoxy which would be a better choice anyway.

Epoxy Grout

Epoxy grout is the top of the line and best choice for any tile application. It can be substituted for sanded or unsanded grout.  It is more sturdy than both as well as being waterproof and stain resistant.

Epoxy is a two or three part chemical consisting of the base and the activator. With some brands the color is an additional part that must be added. Once the parts are mixed a chemical reaction begins. From that point, depending on the brand of epoxy, you have only a limited amount of time to get everything grouted before the grout becomes stiff enough to be unworkable. When it reaches that point, if you do not have everything grouted you are SOL.

To help slow the cure time you can mix your epoxy then put half of it in the freezer. The cold air will slow the chemical reaction and lengthen the working time. You can then work with the other half until it is all used. Clean it up, wipe everything down, then grab the second half out of the freezer and finish up. When you first pull it out of the freezer it will be, well, frozen. It thaws quickly, though, so should be workable within a few minutes. This essentially doubles the working time of your grout and ensures you don’t have to rush through it.

Since most epoxy grouts do not contain sand (or at least not in the classic sense of sand) it will normally not scratch your tile. If you have highly polished granite or marble that’s important. Be sure to test first anyway!

Different brands of epoxy have different working times as well as some being more difficult to work with than others. The brand with which I have had the most luck and the only brand I ever use is SpectraLOCK from Laticrete. It has a longer working time than any other epoxy grout (at least any I’ve ever used) and is virtually stain proof. Please don’t take that to mean the you can grout a jacuzzi with it, fill it with cherry kool-aid, and expect it not to be pink (Don’t do that). It just means that for all intents and purposes it will not stain without concerted effort. In my opinion it is the best on the market.

The only drawback of epoxy grout would be the price. It is fairly expensive. When weighed against the upside, however, it is well worth it. Low maintenance demands and high durability of epoxy grout make it well worth the money.

Picking the correct grout for your application is a key part of a proper tile installation. If you choose incorrectly you could end up with a multitude of problems and headaches. Grout, chosen and installed correctly, will complete your tile installation and push it from a good tile job to a great one. Do not underestimate the power of the grout.

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  • David Choate

    Hi Roger. I am tiling a sunroom floor with 6×24 inch tiles that look like wood flooring. The joints are 1/8 inch and I was told that unsanded would work and I like the smoother feel also. But the more I read I’m concerned that I should use sanded for the durability and less shrinkage. We live in a colder climate and when the temperatures get below freezing will probably not heat the room so there will be pretty severe temperature fluctuations over the year. Does the shrinkage referred to in unsanded grout only concern drying shrinkage or temperature shrinkage as well? Any recommendations? Also this is a recently enclosed deck so it will be exposed to more moisture and humidity does that influence my choice? Thank you.

    • Roger

      Hi David,

      The shrinkage only refers to the time until cured. Once cured it will not shrink any more (significantly so, anyway). You can use either, one will be just as durable as the other once cured. I would use sanded, but the unsanded will work fine although you may need to go over it again once it gets an initial cure and shrinks. Remember, although the grout lines are only 1/8″ wide – they are still as deep as the tile is thick. So you’re still filling 1/2″ or so deep grout line, that’s a lot of room for it to shrink.

  • Steve

    Hi Roger, I’ve learned a lot reading your posts so first off, thanks for the informative site.
    I have a question about grouting with two different colors. The field tile grout will be a gray and the liner white.
    Liner is a single band of 4 x 12 faux marble which will also be the tile for the niche.
    Grout all the field tile with the darker color first, then tape off the field tile and grout the liner? We’re using spectralock pro.
    Many Thanks

    • Roger

      Hi Steve,

      Yes, always grout with the darker grout first. You can get white grout off of black grout, you cannot get black grout off of white grout.

  • Jeff

    Hi Mr. Elf,
    My bathroom tile (floor and shower walls) is 4.25 x 4.25 inches, glazed white ceramic. It’s fairly old. The lines are 1/4-inch wide, cement-like, and rather dark. Parts of the floor around the toilet smell (mildew, or old urine type of smell) when they get wet. Not an overwhelming stink, but a lingering smell that once you notice is hard to ignore. In various places on the floor and shower, a wet toothbrush will seem to corrode the grout (dark color water runs down, with tiny specks of grout in it). Am I right in understanding these grout lines are large for the tile size, and thus might complicate efforts to redress the problems? And what would be the best way to address these problems? I’ve looked into epoxy grout, sanded grout, but gotten conflicting opinions. Thank you. I uploaded pictures it helps any diagnosis.

    • Roger

      Hi Jeff,

      Yes, those are huge grout lines for that tile. Grout is a porous product, which means it will soak in liquid (of any type). Urine is an acid, which will eventually corrode the salts in cementitious products. It should be sanded grout in those lines, but if it was not packed in properly in lines that large it would not have been stable enough to last. Another issue is movement in the tile, which would eventually erode the bond of the grout to the side of the tile and cause it to become unstable.

      The best first thing to do is see what is beneath your tile. This can be done easiest by looking at a spot like a heater vent or something similar where you have sight access to the entirety of the layers.

  • Dave

    Hey Floor Elf,
    I have learned a ton from your site. In your article on grout you recommend SpectraLocke from Lactricrete. Unfortunately I cannot locate a supplier of this brand within 250 miles of me. I have access to TEC Power Grout 550 from several retailers in the area. Have you had any experience with this? I have read some reviews talking about this not curing and washing out. Any thoughts? I look forward to your feedback.

    • Roger

      Hi Dave,

      Power grout is great stuff! When it was first introduced they had some issues with it, but they reformulated it about three years ago and I haven’t heard of any of those issues since then.

  • Brad

    Hey Roger, I am preparing to do a kitchen backsplash that will have white glass subway tile for the majority and a white honed marble herringbone over the stove. My current problem is finding out what type of grout to use for this. I followed your preference with the spectralock epoxy for a ceramic tile floor I did not to long ago and absolutely loved it. Now I want to use this on my kitchen backsplash. My only concern is the potential for the sand content in the spectralock to scratch the glass tile (I’m not too concerned about the marble since it will be honed and not polished). Have you ever used the spectralock epoxy grout on glass tile without scratching? I will test one tile out before using it to see if it scratches when I rub it with some grout. If it does scratch, could I protect the tile using clear packing tape?

    Thanks,
    Brad

    • Roger

      Hi Brad,

      I have used it SEVERAL times without an issue. You do need to test it out, but you’ll likely be just fine. If it does scratch there are other grout options that will work better for your application. A one-component acrylic-based grout may be an option.

  • Cathy Stahl

    I am only replacing the grout where the wall meets the floor in the shower. Caulk is a pain because it does not last. This epoxy sounds like the best stuff and it will not take much. Is this something that sounds like it will work well for that? I am going to do it myself and I am a stay at home mom that can be pretty handy.

    • Joe

      Hi Cathy, please whatever you do, don’t put any type of grout where your wall meets the floor. Thats a “change of plane,” meaning, where the wall and floor form the 90 degree angle, those are two different surface “planes”. There is always a tiny bit of movement between planes, however imperceptible it may seem. This movement will cause grout cracks and eventually water leaks and damage. Silicone can flex with this movement and still keep the water out. I recommend you repair any grout and/or silicone that had mildew growth in it, then keep a spray bottle in ur shower or bathroom. Put a half-cap of bleech in the bottle and the rest water. After every shower just lightly mist the walls. I can assure you this will keep the growth down.

    • Roger

      Hi Cathy,

      It does seem like the best stuff, but your walls are still going to expand and contract and the grout is still going to become unbonded – epoxy or not. Or, even worse, since epoxy is normally stronger than the tile, rather than the grout becoming unbonded from the tile – all that movement is built up and release with your tile cracking rather than the grout.

      It needs silicone, it compensates for that movement. Grout can not, it should never have been grouted to begin with. :)