Using the Correct Type of Grout

by Roger

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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Chuck

I used unsanded grout in a 1/4 inch grout line. It has cracks and does not fill the grout line to the top of the tile. Can I use epoxy on top of the unsanded grout. Any suggestions?
Thanks,
Chuck

Reply

Roger

Hi Chuck,

You can not use epoxy over the unsanded, you can scrape the unsanded out and use the epoxy.

Reply

Greg

Hi Roger,
I need so grout advice and the more I read the more indecisive I get. 2″ x 2″ floor tiles, 13″ x 13″ wall tiles and a 12″ x 12″ mosaic that is comprised of 1/2″ square glass and stone. We are going to cut them into 4 inch strips and use as a horizintal inlay around the shower and in the niches. The grout lines for the field tile will be 1/8″. The inlay mosaic tile says to use unsanded grout so as not to scratch the glass. I’d rather use sanded. Another option would be something like Fusion Pro or Flexcolor CQ, but they are about $55 per gallon and I think I would need slightly more than 1 gallon. That is a whole lot of difference in money. Is there a way to grout with sanded and not scratch the glass or should I go with something like flexcolor CQ?

Thanks,
Greg

Reply

Roger

Hi Greg,

Unfortunately the flexcolor would likely be your best bet. You can always test the sanded grout on the glass to see if it scratches. It may be just fine.

Reply

Gretchen

Hi Roger,
We are about to have a contractor come to install honed marble mosaic tiles (12X12 sheets of 2″octagon with small grey diamonds at each corner). They are very tight lines, probably about 1/16″ but a few look a little larger. I am a little nervous after reading about so many problems. From what I understand, we should probably seal them prior to install, and again after. From what you are saying epoxy might be our best option for grout? (Particularly since I am considering white grout). We are supplying the materials and I have not had much feedback from the contractor on what he thinks we should be purchasing (a red flag?). Any thoughts you have about the grout and/or sealer are truly appreciated.
Thanks!!!!
Gretchen

Reply

Roger

Hi Gretchen,

With white grout I would HIGHLY recommend an epoxy grout, it is your best option. Did you ask him what he recommends? I know I normally don’t suggest a lot of products, especially ones with higher price points like epoxy grout, without being asked for an opinion on the matter. So no, it probably isn’t a red flag if you haven’t asked him. :D With white grout you will not need to seal them before grouting. However, if you use epoxy you can seal them before (easier) or after. If using regular cementitious grout seal everything after.

Reply

Judith

Hi Roger,

We’re in the middle of a kitchen expansion and tile company did not order the right shade of grout. What are your thoughts on Power Grout versus other grouts? What do you think of grout additives? We have 12X24″ porcelain tile with a 1/8″ grout line. What is the best grout or combination that will keep it’s ‘coffee’ color, resist staining etc.?
Thanks!

Reply

Roger

Hi Judith,

Power grout would likely be your best option. I hate grout additives. :D

Reply

Steve

Hi Roger,
I am installing tumbled marble mosaics (12″ x 12″ mesh) for my shower floor. The substrate consists of Wedi Fundo shower pan attached to Advantech using Bostik PM premium modified thinset. After install, I read where I should have scarred the Advantech…arghh! Wedi instructs to attach using epoxy grout. My concern is the potential for movement between the Wedi and Advantech since I did not scar. Would you recommend proceeding with SpectraLock or should I consider a Fusion Pro or urethane type grout?
Thanks much.

Reply

Steve

Sorry…The sentence should have read “Wedi instructs to GROUT using epoxy grout”.

Reply

Roger

Hi Steve,

You should be fine. You can use any of those grouts without problem.

Reply

Eve

Hello the floor elf. This past Spring, my contractor finished my complete bathroom remodel (moved around the plumbing, the door and recreated the whole thing). The shower is a VERY large stall with subway tiles on the walls, with 2 lines running thru it of the matching tile from the floor which is; frosted glass penny rounds I got from a wearhouse sale of a prestigious Tile manufacturer near me and concrete slabs on the inset shelves, step into stall, tops of knee walls and the bench. The grout on walls and shower floor is Sanded TEC.
My issue is on the floor a super fine visual crack has emerged in the grout and I’m not sure if it’s surface only or not. ALSO, directly under the lip of the concrete slab step into the stall where there are glass tiles and sanded grout on the 1.5″ wall between that step and the floor, a chunk of grout has come out. a chunk the size of my upper part of pointer finger (from the middle joint of my finger to the tip of it). I bought sanded TEC epoxy of the same colors as the grouts (charcoal & natural white).
Should I just fill that hole myself as planned and also run the epoxy grout over that super fine crack and call it a day? :rockon:
thanks in advance for your help. (I’m not even sure this website is active. there are no dates I can find) :whistle:
:corn:

Reply

Roger

Hi Eve,

Of course the website is active! My wife makes me do stuff to leave her alone. :D

The cracking could be a NUMBER of things. I would begin by using that epoxy and go over the hairline crack and fill the other area as well. If nothing else cracks or comes out you’re fine. If it begins to have problems in other areas of the shower we can figure out at that time what the problem may be.

Reply

Eve

cool, Roger Elf. I will apply the epoxy grout soon. thanks and I’ll let you know what happens. :whistle: :corn:

Reply

Mevi

I have a 1992 motorcoach with a beautiful granite tile floor in the bathroom and kitchen. The grout has cracked and chipped over time, and I would like to clean it all out and replace it. Considering the flexing of the coach on our less than perfect US highways, should I use epoxy grout or just stay with the original sanded type? The finish of the tile has aged to more of a satin finish, so scratching is not an issue. Thank you for your help.

Reply

Roger

Hi Mevi,

Epoxy is actually brittle. Bulletproof, but if flexed enough it will likely chip. You would be better off with a urethane-based grout.

Reply

Archie

Help please. I just finished putting up a mosaic tile backsplash ( glass, travertine, and stainless steel ) grout lines are less than 1/4 inch. Maybe 1/8. Can I , should I use epoxy grout ?

Reply

Roger

Hi Archie,

You can if you want to. No reason at all that you can’t.

Reply

Wilma

Doing a bathroom remodel and will be laying tile on the floor and in a newly installed shower stall. As inexperienced tilers, we’re scared to death of epoxy grouts. Picked up my tile today from the shop and they recommend using Power Grout by TEC. Been reading some reviews and there have been some complaints about using this in showers. Grout seems to be washing away. Others report no problems. Value your thoughts!

Reply

Roger

Hi Wilma,

Power grout has been updated and they are no longer having the problems they had with it at first (washing out). It’s good stuff.

Reply

CliffStoll

Very wide grout lines … Like half an inch or more ?

We’re installing flower tiles in the shower – these are not rectangular, but in the very shape of flowers and leaves. In fact, they are exact pressings of flowers and leaves from our garden (handmade tiles – yep, they are vitreous, completely impervious, and quite strong).

Some of the tiles are long, curvy stems (3/8″ wide and about 4 to 8 inches long). Other tiles are flower and leaves — about 2 to 4 inches across. They have edges that curve all over the place, just like flowers and leaves. (Think of life-sized cat-tails and lilies) Thickness is uniformly 1/4 inch.

It’s almost impossible to cut rectangular tiles to fit between these curvy shapes. So we’re resigned to having 1/2 inch to 1 inch wide grout between the field tiles and the flower stems and leafs, and between the flowers and the leaves.

I’m thinking that an epoxy grout is the way to go. (it’s over pink Kerdi, on the shower wall). Or, we could use little mosaics to fill in spaces, but this will detract from the very elegantly curved flower tiles.

Ideas? Thoughts? Suggestions (alcoholic or otherwise)?

Reply

Roger

Hi Cliff,

Epoxy grout will fill areas that large if you need it to. No problems there.

And what the hell is pink kerdi? :D

Reply

CliffStoll

Aha! Many thanks — any suggestions for getting smooth areas on vertical walls with epoxy grout?

Oh – my Kerdi looks orange now — got rid of that red light in the ceiling…

Smiles all around!

Reply

Roger

Let it set up a bit longer than normal, and use a micro-fiber towel to wipe rather than a sponge for your final cleaning.

Reply

CliffStoll

Happy thanks to you, oh Roger-Elf …

You’re a benefactor to humanity!

Reply

Karen

Roger, you told Mr. 1500 that he could still use Laticrete’s SpectraLOCK epoxy mix with non-sanded grout. To be clear, are you saying I can use Latricrete’s Parts A and B with another company’s non-sanded grout? My spacing is less than 1/8″ I definitely do not want to use sanded grout! I also definitely do not want to have to do a second application of a sealer. (This is for shower walls. I will use sanded on the shower floor.)

Have you had any luck with the StainBlocker product? What do you think are the best for use with non-sanded grout when looking for stain and water sealing walls?

Thanks

Reply

Roger

Hi Karen,

I did not tell him that. He can use epoxy OR unsanded, if he uses the unsanded he needs to seal it. You CAN NOT use the A and B with any other colorant or grout other than spectralock part C. Never used stainblocker.

Reply

david

roger,i am installing porcelain tile 1/4 thick. On a bathroom floor over hardiebacker board. Have polyblend sanded grout. Is that a good choice or should use a epoxy grout your talking about. If I use the poleblend does it need sealed

Reply

Roger

Hi David,

I hate polyblend. That said, regular sanded grout (like polyblend) will work fine, the spectralock is simply the next step up. If you use sanded yes, it should be sealed – the epoxy doesn’t need to be.

Reply

Clare

Mr Elf,

I have an epoxy grouted shower floor ,which I love, with flat topped pebbles.I have just started to notice tiny little mold type stains that do not come off the pebble surface. I want to take care of it before it gets out of hand. We have well water with deposits that we deal with also. Any suggestions?

Reply

Roger

Hi Clare,

Short of physically drying out your shower floor after every use, just regular cleaning with a good ph neutral stone cleaner is likely your best option. You may also want to try a product like oxy-clean, the oxygen bleach will remove any organic materials on the surface of your stone.

Reply

Kandy

I am having to re-grout our shower floor in a house we just purchased. The previous owner’s used sanded grout, but did not use a sealant. Around the drain, the water seems to puddle for a moment before draining. Should we continue with the sanded grout or use something else? The joints are super thin, as the tiles are probably one 2″x2″? Would appreciate any and all input.

Reply

Roger

Hi Kandy,

Use sanded grout. Sealant is not required for grout in a properly built installation, so I’m unsure where your reasoning derives? If the water ‘puddles’ for a moment before draining it’s likely not sloped correctly, which is a substrate issue, not a sealant issue. Perhaps I’m just not understanding?

Reply

Eric

Roger,

Wanted to thank you for the information and product tip for SpectraLOCK from Laticrete. The epoxy grout is really easy to keep clean – very little staining and virtually no mildew. Just based on the cleanliness factor I’m not sure why every tile shower and bathroom floor is not done using epoxy based grout.

Homeowners spend a lot of time scrubbing and sealing grout lines. My take is that the labor required to maintain non-epoxy grout products makes these products a far more expensive option.

Thanks again for the information.

Eric

Reply

Brian

I’m using a premium porcelain tile (1’X2′) also very Glossy, for an entire bathroom with shower. What kind of grout should be used? It’s also spaced ¼”. If I had to guess, the tiles are around ⅜ thick.

Reply

Roger

Hi Brian,

You need sanded grout for that.

Reply

Mr. 1500

Oh crap, it looks like I can’t the epoxy stuff. I just read this on their site:

“LATICRETE SpectraLOCK Grout is a sanded grout. Use of sanded grouts in joints less than 1/8″ (3 mm) will result in a coarser surface texture as compared to wider joints.”

So, if I use a non-epoxy unsanded grout, please recommend a sealer.

Thank you!

Reply

Roger

You can still use the epoxy. If you use unsanded Miracle sealant’s 511 impregnator pro is a very good sealer.

Reply

Mr. 1500

Greeeting fellow Coloradan.

Epoxy grout sounds like a great idea for the shower I’m working on. One question though; do you seal it?

Reply

Roger

Nope.

Reply

MJ

Roger,
Do you have any formulas or suggestions for calculating how much grout is needed? Personally, I am installing 2 x 4 x .5 inch marble tiles as a backsplash, and have calculated the square footage to be 23 square feet. I’ve seen grout calculators at manufacturer sites, but they give drastically different results. I’d also like to calculate how much mastic or thinset I’ll need. Thanks for any info. –Mike

Reply

Roger

Hi MJ,

DO NOT use mastic on marble!

You can get grout in 5 or 10lb (depends on manufacturer) or 25lb – the smaller should suffice for your backsplash.

Reply

Jaren

I am installing shower tile. The tile chosen is a natural stone mosaic with many different shapes. Some of the areas between the stone that need grout are 2/3 in. Most of the grout lines are smaller than that, as little as 1/8 in. I am also installing 1.5 foot wide glass tile vertical line in the center of the wall, with the stone on either side. I am installing over hardiebacker board. What is the best mortar and grout for this type of tile instillation? I am looking for long term water, mold, mildew resistance.

Reply

Jaren

I should mention that the stone mosaic is on a mesh backing.
Thanks!

Reply

Roger

Hi Jaren,

A sanded or epoxy grout needs to be used with the spacing you’ve mentioned. However, the long-term water, mold and mildew resistance you’ve mentioned lies almost entirely on the waterproofing method of your substrate, not your grout or thinset. Your best option there is a topical waterproofing method. Any good modified thinset will work just fine.

Reply

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