Grout Does Not Stabilize Tile

by Roger

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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Linda

We installed small mosaic tiles on our shower floor – there is thinset that has come up between some of the tiles that didn’t get cleaned out and has now dried. Do we need to get this thinset out from between the lines or can we just cover it with grout? Both thinset and grout are while. If we need to removed the thinset, is there a good/easy way to do it?

I’d really rather just leave it, if possible… I’m awfully tired of this project!! :censored:

Thanks!

Reply

Roger

Hi Linda,

Unfortunately it will need to be removed. Although they are both white, it will never match. White is actually the most difficult color to match. You can get a grout saw and that would be the easiest way to scrape the thinset out of there.

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Susan

Hello Roger,
I have purchased a mosaic tile with very small pieces of marble as a design feature for the floor of a master bathroom. Many of the tile pieces are so close together that it will not allow for grout to get in between them. I am concerned that without enough grout between the small pieces that dirt and or moisture will get in between these small cracks and eventually mold would begin to grow.

Should I return the tile and redesign my floor? Thanks again for your help :)

Reply

Roger

Hi Susan,

If dirt can get it, grout can get in. :D If you want use your regular sanded grout and, once cured, go over the mosaic with the same color unsanded grout, that will fill in any really tiny gaps the sanded did not get.

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Susan

Thanks! The mosaic tile is polished marble – is it okay to use the sanded grout on it?

Also, on a somewhat unrelated note; I went to a tile laying class where they explained the prep for laying tile on the floor. They suggested the following in this order (up from the subfloor):
– vapor barrier (will use redgard)
– self leveling compound if necessary to level floor
– thin set
– hardie backer board installed while thin set is still wet
– thin set
– schluter ditra
– thin set
– tile
Are all these steps necessary to insure proper installation? What steps do you use to prep for a tile floor?

Again – ever so grateful for your elfish wisdom!

Reply

Roger

Hi Susan,

Good lord! Are the people running the tiling class trying to sell you product too? (Don’t answer, I already know. :D )

If you have a wooden subfloor you need a total of 1 1/8″ of ply above the joists. This usually is just an additional layer of 1/2″ over your existing 5/8″ or 3/4″. After that, if you have a crawlspace or other area below from which you need to control vapor entering the structure, then yes, you should use a vapor barrier. But that’s rare (around here, anyway). If, at that point, your floor is out of level MORE THAN 1/2″ you should use slc. If is it not you don’t need to use slc. You DO NOT need hardi beneath ditra, it can be installed directly to your second layer of plywood. Then thinset, then tile.

So, from the subfloor:
1/2″ ply
thinset
ditra
thinset
tile.

Beer.

Don’t forget the beer.

Reply

Dave

If you have joists and 5/8 plywood and then deck mix for a shower pan is that okay?

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Roger

Hi Dave.

Yes.

Shortest. Answer. Ever. :dance:

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joseph

Hey devil dog,

I am going to use spectralock. I have read horror stories about using though. The guy at the local tile supply told me how many SC tile guys dont use it cause its a pain. But I want it for the durability and stain prevention. Can you tell me how to avoid common pitfalls using it such as glazing? Do i wait to wipe with sponge or wipe immediately? Whatever info you can give me, I appreciate.

Reply

Roger

Hi Joseph,

Sure, here you go: Working with spectralock :D

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Angelique

This is interesting! I was just reading questions from people who were asking if they could use clear silicone instead of grout for their glass mosaic tiles. (They weren’t happy with their grout color options.) The people answering the questions all said, “No way! You need grout to stabilize the tiles!” From what you’re saying, that’s not true, BUT I have to worry about moisture getting behind the silicone.

I’m interested in what you have to say about using 100% clear silicone instead of grout for glass mosaic tiles because I’m planning a bathroom right now, and I’ve found tiles I love, and it would be great if I didn’t have to worry about the way grout will change its look.

Reply

Roger

Hi Angelique,

Grout will, TO A VERY SMALL EXTENT, stabilize the tile. But not in the manner that everyone thinks it will, that’s why I stated that. You DO NOT want to use silicone as grout, especially in glass tile. When water gets behind it, and it will, the silicone will trap it behind there and it will fester. Not only will the tile look funny with random water pools behind it, once the mold begins to grow you’re gonna have a tie-dye looking shower.

Gross, huh? :D And silicone is not made to be a permanent product, it is made to be removed and replaced as needed. Ever see the bead of silicone in a shower that has begun to pull away from the tub or tile? It does that because over time it will lose elasticity and begin to shrink. So…another reason not to use it.

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jLo

Oops! While setting 12×24 tile in a shower, one of the tiles slid down and dried severely out of alignment. Is there any way to remove and replace this tile without compromising the Kerdi Board? …or should I just keep drinking?

Reply

Roger

Hi jLo,

Keep drinking. :D The quicker you get to it the better. You don’t want to pull or pry the tile off, you want to ‘sheer’ it off. Use a drywall or putty knife and a hammer to get it between the tile and board. Sometimes you can save the board, sometimes you need to patch it. But that’s the best way to get it off of there.

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Mark

Hi Roger.

I am having a new bathroom installed at the end of next month.

I have picked some stainless steel faced tiles for the splash-back behind the new bathroom sink, but due to budget constraints will have to do this bit myself- what started off as a £200 repair to a leaking pipe in the bathroom now requires that the whole room is gutted. The leak had rotted away much of the under floor joists, and so on and so on, and had clearly been leaking away for many years.
Even the “box” the hot water tank is in now unstable as the bottom of it is a mushroom farm. :shades:
Now I know why I have had a problem with condensation…… :roll:
As an aside the leak was not from a defective shower installation, but from a mains-pressure cold water pipe that had rubbed through on a pipe clamp under the floor in the 28+ years since a plumber failed to do the screw up all the way, leaving it to rub on the pipe, and eventually rub trough.

I am finding it hard to find a grout that is OK for the tiles. They suggest “un-sanded” (grout lines about 3mm) but in the UK grout never seems to say “sanded” or otherwise.
Tiles here.
http://www.ebay.co.uk/itm/Sheets-Of-Brushed-Silver-Stainless-Steel-Mosaic-Tiles-037-/331066771860?pt=UK_Wallpaper&hash=item4d151e0994
Any suggestions as to what to use that I can actually buy in the UK?

Reply

Roger

Hi Mark,

You can use either type of grout for those. I can’t really be more help as I don’t know what you have available over there. With those size grout lines you can use either type, though.

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Mark

Thanks. I Love your honesty, Better to say you aren’t sure than to give bad advice. The sign of a true professional.
I guess I will just dig a bit deeper into my pockets, and pay to get it done properly with the rest of the work.

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Joe Halpert

What is the best grout to use in a tiled swimming pool?

Reply

Roger

Hi Joe,

The guys I know who do swimming pools use epoxy.

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Megan

Hi Roger,

I installed a pebble/river rock tile for a shower pan. 85% of the little rocks were hand laid around the store bought “squares” filling in the gaps. I used Thinset morter to “glue” the rocks to my concrete shower pan (propperly pitched and layered, thanks to your other posts) My next step is to grout however I am seeing some of the rocks are loose and a few have completely popped off, Can I mix up some thinset stick it to the individual rocks and put them back into the pattern? Or do I have to remove all of them and the thinset and start over?

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Roger

Hi Megan,

You can just replace the ones that have come loose.

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Carly

Ok….I didn’t want to do this – but I have to. I have adhered 12 x 12 ceramic tiles to a linoleum kitchen floor….using hard as nails. Working very well….but my ceramic tiles were caught in the rain (storm) a few days before I laid them and must have still had enough water remaining in the ceramic to cause a problem. Tiles laid perfectly. Stuck nearly instantly. In the morning….knock knock…half of them hollow. I have popped the hollow ones up and let the dry…..and easily scraped the water affected hard as nails off the floor. Have cleaned etc and ready to go again….but before I do…I am open to hearing about the holes in my logic and wondering if I should pull them all up in the efforts to ensure they are all dry through.

My biggest question is: what grout will be the best? I don’t know if I require one with some flexibility – as I want to create the strongest bond possible between the tiles without cracking.

Any advice, comments, or scornful opinions welcome. Im not trying to reinvent the wheel or build a castle that will be here in 300 years – just want a floor that I dont need to fix every other day for a couple of years until this house is bulldozed.

Reply

Roger

Hi Carly,

You’re not going to get a grout that will not crack. Even flexibility won’t last in that application (and they are hard to find and expensive). You already know the flaw in the logic, that’s why you typed the first sentence. :D It is simply not a proper application nor correct products, an inferior, unstable substrate improper bonding products. I honestly don’t know what to tell you to use, nothing I’m aware of will last there.

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Carly

Thought so. I hate it when Im right about being wrong.

So, here’s what I’m going to do…..please bear with me. I have, in the meantime between my post and your’s – reglued the tiles that lifted. They’re not going anywhere for a loooong looong time. I know it’s not the right way to do it – but it’s working for now.

So, if just for a minute we pretend (give me a break, I’m a girl) that there are no holes in my theory – what would be the most effective grout to use? Also – here’s another thought to throw at you….would using a piping bag to get the grout in and around and little spaces around the tiles be of any benefit or greater ease at all? It seems like it may be a little less messy and more effective?

Thanks Roger!

Reply

Roger

Use a urethane grout. No, a bag would take more time, be more tedious and difficult, and actually lead to less grout in the small spaces.

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Carly

Hi Roger,

Thank you very much for your advice. Guess what we did….pulled them all up – and pulled the linoleum off the floor….sigh….and we now have a proper floor to adhere the tiles to….with real mortar….and will then use real grout. Why oh why can we send a man to the moon and not have an easier method to stick something to the floor?

Reply

Roger

It is easy, you just need to remove the existing flooring first. If that’s done there’s nothing terribly difficult about it at all.

If you have any more questions can you PLEASE post them as a reply to my answers? I have (literally) over 15,000 questions and answers here, when you start a comment like ‘guess what we did, pulled them all up…’ I need to go searching for your name and email address, find the comment, read it and my answer, then I can begin reading the second sentence because I know what the hell I’m reading about. :D Thanks.

Reply

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