A common misconception about tile and grout is that grout will somehow assist in stabilizing a tile installation. It does not. Unless you use epoxy grout it will add no significant structural elements at all.
So why should I use grout?
Grout is, structurally speaking typing, simply there to fill the spaces between tiles. That is an oversimplification, but it describes the grout’s function. More to the point, it is there to keep other things out of that space. Without grout the possibility of dirt, grime and all sorts of unruly, unwanted things may collect in the spaces between tiles. This may lead to not only unhealthy conditions, but also the chance of damaging your tile while trying to remove those things.
Does epoxy grout help stabilize tile?
If you’ve read any of my other posts regarding grout you have more than likely seen me state that epoxy is different. This subject is no exception.
Epoxy grout will actually add to the stability of your tile installation – to an extent. Epoxy will stabilize only the area between the tiles – the grout lines. It does not stabilize your tile enough to replace proper installation methods. This is not what epoxy grout is intended for.
A couple of reasons for using epoxy grout include the durability, ease of cleaning, and its ability to withstand staining. It is not intended as a product to make a sub-par installation correct.
How does epoxy help?
To the extent that it does stabilize your tile, it will only do so in the direction of the plane. If you think about tile on a floor epoxy grout will not (to any significant amount) stabilize your tile up and down. If you have a corner of your tile that does not have support beneath it, the tile will still crack eventually. It will take a bit longer because of the epoxy, but it will still crack.
If you have two tiles (not installed on anything) that are held together by epoxy grout between them you can grab each end and bust them over your knee like you would bust a baseball bat (if you were insane) and they would break apart. You can not pull them away from each other and pull them apart – ever. That is the direction of the plane.
So although epoxy grout does add some stabilizing features to your tile installation it should not be used in that capacity.
Grout is an integral part of a correct tile installation but not in a structural way. As you plan your installation keep that in mind and treat your grout simply as an aesthetic part of your overall project. It will not assist in stabilizing any part of your tile. You should only be concerned about the color.
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Hi Roger,
I’ve been lurking on your site for a while now. LOVE it! Here’s my question:
I laid mosaics in the bathroom and they are not sticking to the flex bond. I have not grouted yet. There is 1/4″ hardibacker thinsetted to a super solid plywood sub, then flex bond thinset on the hardibacker, then the tile. I’ve been working in the bathroom, stepping on the tiles and some of them are coming loose. I’m hoping I can grout, and they will stick, but I’m afraid you going to tell me to tear up all of the tiles. As to why they didn’t stick, was my thinset too dry? Thanks for your input.
Hey Bill,
It sounds like you may not have gotten full coverage under your mosaics. You’ll get better coverage if you comb out the thinset then flip your trowel over to the flat side and knock down the ridges. Then you’ll be laying them into a flat bed of thinset. Use your grout float to pound them down into the thinset a bit to make full contact. Your thinset very well could have been too dry – that will definitely cause that.
You should take them up – if ‘some’ of them are coming up now – how many are gonna come up later?
Thanks for your input. Really smart sounding advice. I’ve started taking up some of them. Scraping the combs of thinset is ridiculously difficult. I’ve gotten myself into a real mess here. I don’t even know how I’d start over if I were so inclined. I’ll keep at it.
Once again, thank you.
So, I just realized that some thinset squished up in between a few of my tiles and cured there. How much of that do I need to scrape down before grouting??
Hi Charles,
You want to go down to at least 2/3 the depth of the tile.
Are you familiar with a product called Grout Boost. You add this to your grout instead of water and it’s supposed to seal it so you don’t have to apply a sealer over your grout. It’s about $80 a gallon and a tile store I went to put this in my estimate of ‘things I needed for the job.’ What is your experience and/or recommendation for such a product?
Is it world of tile?
I can’t stand the stuff, it makes my grout feel weird. That, however, is mostly a personal thing. I have been using the same, or similar, grout for almost 20 years, when something changes the way it works (how workable it is, how it cleans up, etc.) I don’t like it. That’s all it is. The pros that do use it swear by it, and it works. It does what it says it does. But you don’t ‘need’ it, don’t let them tell you that.
Yep! World of Tile! Their mortar and everything else put my estimate at $800 just for the tile. Tile is the cheap part, we’re getting everything else at HD/Lowe’s and saving hundreds of dollars.
I tiled my sons 30 foot hallway and it seems that there are 4 tiles that keep coming loose and I am not sure why. I put down backer board, mixed the thinset and laid the tile. The house has other tiled floors which are fine, it is just the hallway. The hallway is level so I’m not sure why the tiles keep coming up. I have taken them off, cleaned the floor and put new ones down, but some of them are still popping up. I don’t believe the house is settling, since no other floors are doing this. Any ideas?
Hi Tina,
Do you have thinset UNDER the backerboard as well?
No, I didn’t use thinset under the backboard. The house is only 8 years old. I have only recently heard about using thinset under the backboard. Must I take out the tile and cut out that area of backboard and then thinset it?
I think that may be the problem. If there is not thinset beneath your backer it can create unsupported areas of your substrate where the backer is not fully supported and there may be a hollow area. You can try to thinset under that area and it will likely stop cracking there. Don’t be surprised if it begins cracking in a different area down the road, though.
Heavily travelled areas such as hallways and in front of counters tend to move the substrate more than other areas. The constant press and release of weight on those areas may eventually work loose fasteners or cause areas to sag. If not fully supported it may cause movement and, as you’ve seen, crack grout.
Funny, I have never had this happen before. I’ve tiled a couple of hallways and a bathroom without ever putting thinset beneath the backer board. Is this due to poor construction in a newer home?
Technically it’s due to specific point-load distribution in a given area. It may or may not happen, can’t guarantee failure, we can only guarantee success.
This is why standards call for a double-layer, 1 1/4″ minimum plywood substrate beneath your backer beneath a tile installation. Deflection ratio standards for residential structures normally do not meet minimum requirements for a successful tile installation. In short they are constructed to support vinyl or carpet.
Thanks so much for you advice!
Hello Roger,
I am concerned that I may have mixed my grout (unsanded, cementious) to thin. My grout only comes in a 10lb bags and I only needed a fourth of it. I did my best to guestimate that amount of powder and added it to the recomended amound of water. Can you describe the appropriate consistency? Mine was slightly less firm than peanut butter. Where the porcelan 18×18 tiles are perfectly even, the grout does not quite come to the top of the tiles. My grout lines are 1/16 in most, slightly more in a few. There is also some lippage in a few spots. (My husband insisted that once tiles are down, they can’t be taken back up…..grrr!) In these areas the grout appears to not be curing as quickly (looks darker). Fortunately, the grout is almost identical to the tile color. This is our first trial effort, a laundry room before doing the MBR floor only, I think. I grouted 22 hours ago. Can or should I re-grout it, and what is my time window?
I have thoroughly enjoyed reading your blog! So much very useful information. Thank you!
Cheers!
Colleen
Hi Colleen,
Grout should be about the consistency of peanut butter – so yours may have been a bit thin, which will cause it to shrink some. You should be able to go over it again with some unsanded to level it out, just make sure to dampen the existing grout first. The different color areas could be due to light and shadow because of lippage.
Hi Roger, I value your opinion, so I want to ask you: how do you feel about 1/16th spacing on large format glazed porcelain tiles with either a stacked or 1/3 running bond? I’ve had different opinions- some say they could recommend it with epoxy grout no problem, while some say that it will look and be terrible with 1/16 epoxy (lippage, bridges) and will only do 1/8 lines with regular grout plus epoxy-acrylic grout sealer for durability. I know that some really stick to their guns with the 1/16th, but if it will not look straight, I don’t want to do it. What are your thoughts?
Hey Maleka,
It’s fine so long as the tile will allow it. ALL large format tile is cupped to an extent. The good ones have a minimum of cupping and are more forgiving with smaller grout lines. That is one reasons the standards have been changed to recommend a 1/3 running bond rather than 1/2 on large format (any side over 15″) tiles. Epoxy grout, or any other type of grout, has absolutely nothing to do with whether or not a certain size should be used, it’s dependent upon the particular tile. If they’re fairly flat you can get away with 1/16″ on a 1/3 running bond. It’s all due to the amount of lippage you deem acceptable. Once installed you can use any type of grout you want. The grout line size has nothing to do with the durability of the grout in most cases. Sealer only makes grout stain-proof, that’s all it does.
Thanks, Roger. In your opinion, though, have you seen epoxy grout fail over the course of several years? The guy pushing regular sanded + grout sealer said he’d seen lots of Spectralock failures, that it’s overrated, etc.. Says his will outlast Spectralock by decades. Just wanted your opinion since I was set to go with Spectrlock until I heard this. He implied that his grout sealer contained a bit of epoxy but was water-based and thus protected it from stains and sealed it more effectively. Have you seen any bath work with epoxy grout that hasn’t lasted? Thanks for your help.
I think I’ll go with 1/3 or stacked bond!
Hey Maleka,
Forgive my bluntness, but…
He’s full of shit.
I have never, ever seen epoxy grout fail. What I have seen is epoxy grout used in incorrect applications such as a cast-glass installation, however, in situations like that the tile gives out before the grout. In other words, being that movement accommodation was not factored into the installation the expansion in the substrate cause the glass to break and crack. I’ve also seen that with certain ceramics that implicitly state NOT to use epoxy. I have also attempted to remove part of a shower floor when the homeowner decided to order a different vanity and the shower floor was too small. When I went to chip the tile out (grouted with spectralock) the tile busted before the grout even pulled away from the side. It’s durable. Very, very durable.
AND: whatever grout additive he plans on using I can nearly guarantee you it doesn’t have ‘epoxy’ in it. They do have polymers and latex’s in them, but epoxy is a two-part product which gets solid once the parts are mixed. If his grout additive indeed had epoxy in it, well, that would be a very chunky product.
Another person attempting to push a product by down-talking another one. That really, really pisses me off.
You can use whichever you like, of course, but I will tell you the epoxy is much more durable than any cementitious grout mixed with an additive. It will not fail.
Roger, I think he said the epoxy was in the grout sealer, not the grout itself. Maybe something like Aquamix’s grout colorant sealer with epoxy (although he would not tell me the brand name– which should make me suspicious, anyway. What harm is it to come out and tell me?).
In any case, you confirmed what I was feeling and reading online. At the very least, he’s so sold on his method that he’s not well-informed about other options. Either way, I will go with someone else and do the Spectralock. Thank you SO much for your confirmation about epoxy’s durability!
I am an avid rock picker and on a recent trip to Michigan picked up lots of rocks. My husband says I have to do something with them, so I decided I would make a bird bath. The rocks are all different sizes, and incredibly porous so spreading grout between them would be a nightmare. So the questions are can I spread the grout and then push the stones in, which grout should I use, and will it hold up to being constantly wet?
Hey Jocelyn,
I’m an avid square polished rock installation specialist!
Laticrete has what they call the ‘one-step method’ which is normally used for paper-faced glass mosaics. It can, however, be used with nearly any type of stone. Essentially you add laticrete grout (whichever color you’d like) to 254 platinum thinset (white) and set the tile or rocks with that. It’s setting and grouting in one. You can read about it on Henry’s blog here: http://laticrete.blogspot.com/2009/06/one-step-method-install-grout-glass.html That has pictures of the method and a link to a pdf with specific instructions. Should work well.
do you need to seal granite tile and if so should you seal it before you grout ?
Hey Charlie,
Technically you don’t ‘need’ to seal anything. Sealing assists with stain-resistance so if your granite is in a high traffic area such as an entryway or on a kitchen countertop, anywhere that is prone to staining then yes, sealing it will help you keep it clean. Granite is one of the few stones that don’t need to be sealed every time. It’s very dense and therefore very resistant to staining anyway. It’s entirely up to you whether to seal it or not.
If you are using regular cementitious grout then seal it after you grout. If you’re using epoxy or a urathane-based grout then seal it before you grout.
Just about to install epoxy grout on my recently self-installed porcelain 13×13 kitchen floor.
I already bought CEG-Lite. Yikes! I’m a-feared ’cause it isn’t spectralok. Tell me everything will be ok. And mean it.
Hey Anne,
Everything is gonna be okay. And I mean it.
CEG-lite is urethane-based. That simply means it’s a different type of grout than spectralock. I’ve heard it’s good stuff – I haven’t used it. You do need to allow a LOT of time for this stuff to cure – like 7 – 10 days! Also, as you install it stir the grout every time you pull it out of the bucket. And only grout about four square feet at a time and then wash it. It’s a whole different animal, nothing wrong with it at all, though.
You are too awesome for getting back to me that fast! My husband wimped out on me and decided to use unsanded grout (1/16″ uh – what are they called – spaces between the tiles) instead. Know what put him over the edge? We don’t have an epoxy float. Men. Gotta love ‘em.
Hey Anne,
They’re called grout lines.
Or, in your husband’s case, the origin of one of the most *ahem* creative excuses I’ve ever heard in my life! 
I have laid down ceramic tile with adhesive and have not grouted for the past 4 days because tiles keep coming loose. I have resealed them and they are still not dry…Not all pieces just a few here and there. Should I go ahead and grout, or get another type of adhesive?
Hi ‘T’,
Do not grout that tile – it’s not gonna last. What type of ‘adhesive’ did you use? If it’s the pre-mixed stuff in the bucket it never will fully cure – it’s the wrong stuff. You need powdered thinset sold in a bag which you mix with water. I’m also unsure about what you mean when you say you ‘sealed’ or ‘resealed’ them – why are you doing that?
Hey Roger,
Bob
I am at the point where i am ready to grout my 18″x18″ marble tile. I have done the entire shower, a 32″ wainscot on all walls & the floor. I was wondering about the epoxy grout. Would it be beneficial to use it, & if so, is there any disadvantages to using it & is there any tricks to using it? Also is it an additive or do you buy it already as epoxy grout? Thanks again for all your help.
Hey Bob,
Epoxy is beneficial in many ways – the largest being the stain-resistance and ease of cleaning. About the only disadvantage is that it is a bit difficult to install – you’re on a time limit. Spectralock is the easiest to work with, but even with that you have 80 minutes before it sets up too much. If you use epoxy pay very close attention to the instructions and time limits – follow them. Epoxy is normally a two or three part product – once you mix it up it activates the grout – that’s when your time starts. All of the parts are included when you buy it.
not to change the subject but:
When you are doing a layout with “en pointe” with the tiles all at a 45 degree angle. Let’s say you are going to do three rows of full 4″ tiles , with two rows between them and then cut half tiles top and bottom to fill it all in. The tiles are 6″ on the diagonal, so the whole shebang is about 18″ top to bottom, and it goes side to side as long as the wall. now for the question: Suppose you were going to do a small shower stall, two side walls and the back this way. How would you lay it out so it was 1. easiest to install 2. looked good. easy to install is avoiding little tiny pieces of diamonds or triangles at the corners. Looking good is having some symmetry on the back wall, and some thing besides randomness at the corners.
Hey Geoff,
I start by making my center line on the back wall and measuring from there to the corner. If your tile is indeed exactly 6″ point to point and your center line is 29 1/4″ from the corner then start with a full tile centered on your center line. This will give you a piece a bit under a full half at each corner and eliminate any small pieces. Just figure out which spot gives you the bigger piece at the corner – a tile centered on the center line or butted against the center line. This will also allow you to wrap the design around the corner (match grout lines in the pattern) without any little pieces on the side corners. It also makes the walls symmetrical.
Sounds like you know your stuff, thanks for the great tips!
Good article, very helpful!
Thank you Andrew.
Dan,
You are absolutely correct! Grout can stick tiles together. If you are removing 6 or 7 tiles stuck together by grout I can guarantee one of three things:
1) It is epoxy grout. or
2) The tile was installed and grouted prior to 1983 when lime was still mixed into the cementious grout. or
3) The contractor that installed the grout used the “old school” style of mixing your own grout using portland cement as a base.
These things do not make your tile more stable – they simply make them stick to one another using grout.
If your tile sounds hollow beneath it means there is not full coverage of your setting material and, in turn, not full support. It may very well last for years – as long as you do not step on the unsupported area between two supported areas. Just because something was not installed correctly and lasted for years does not mean people should take a chance doing it that way.
People spend large sums of money on products to re-tile their homes – I don’t want them wasting that money then improperly installing it. That is the entire reason for my site. Why take a chance that it may last for years when you can properly install it and guarantee that it will?
Here’s a quick example using your scenario above – I can take two pieces of paper and glue one end to another. When I pick one up – the other comes with it. The glue added absolutely no stability to the pieces of paper but it did stick them to one another. Take two pencils and lay them apart about a foot. Now place the paper on top of them. The center of the paper still bows down and touches the table, yes? Do the same with a tile then step repeatedly in the center of the tile – it won’t last because it is not fully supported. That’s what I mean by adding stability to a tile.
Roger,
You say that grout adds no support to the structural integrity of a tile installation. I think it does add some stability. Look at this example. I have removed many tile floors that were installed incorrectly, in this case having no bond to the substrate. The tiled floors can last years and have a hollow sound. When you remove the tile, you can remove large areas of maybe 6 or 7 tiles stuck together by only grout. This is the only thing that has kept this floor together for years.