Your grout is cracking for one reason and one reason only: your tile is moving. That’s it. Okay, that’s not it – Unless your grout is non-sanded and was installed in the last 28 days – your tile is moving. That’s it. Yes, 28 days has significance, it is the amount of time it took my teenage son to clean his room. It is also the amount of time it takes for grout to fully cure.

So let’s figure out why your grout is cracking:

Your grout is newly installed – incorrectly

If you do have grout that was installed within the last 28 days then your grout is not actually cracking – it is shrinking. Either your grout lines are too large for non-sanded grout (smaller than 1/8″)  or it was incorrectly mixed. NO! You cannot simply mix up more and fill it in. Read this post about adding more grout to your grout lines.

If your grout is not fresh, well, you need to repair the reason your tile is moving. And stop using your pogo stick in the house. Diagnosing the reason your tile is moving is extremely varied. It could be anything from inadequate deflection in your flooring for the type of tile all the way up to and including the aforementioned pogo stick.

The most likely reasons your tile is moving:

Your tile does not have proper thinset coverage

The most common reason I run into is improper coverage. This simply means that there is not enough thinset beneath your tile to properly adhere it to your substrate and support it. If there are any unsupported areas beneath your tile along the edge or in the corner of the tile, walking on it will eventually work what little support it may have loose and the tile will move down and up every time you step on it. The tile moves, the grout does not. The grout loses the battle and starts to crack out. By ‘crack out’ I don’t mean like that ridiculous Intervention show on cable, I mean it will start to crack and come loose.

To fix this you need to remove and properly reinstall the tile. If it is only one tile it may be an isolated incident in your installation and you will be fine. If you have cracked grout all over your tile installation it was either improperly installed or . . .

Your subfloor is moving

If you have a wooden subfloor and your tile is directly installed to it – go pick out new tile. That is more than likely an improper installation. While tile can be installed directly to plywood it requires a VERY specific method. And I do mean very specific. More than likely it is simply installed improperly probably by someone that did not know any better. If it was properly installed over plywood, well, your grout wouldn’t be cracking. Start reading this paragraph all over. Or . . .

Your backerboard was improperly installed

If you have Hardiebacker, Durock, or any other type of cementious backerboard beneath your tile it should have been installed in the proper manner. It needs to have thinset beneath it, it needs to be screwed down (properly), it needs proper spacing, etc., etc. Read How to Install Backerboards for Floor Tile to see all the things that should have been done.

More than likely there is no thinset beneath your backerboard. Thinset is not used to adhere the backerboards in any way – it is used simply to fill voids beneath the backerboard. It is placed there specifically to prevent your tile from moving. Moving tile leads to cracking grout. But you knew that – or you should start reading this page all over. This would be another time to start shopping for new tile.

Other reasons your tile is moving

You do not have expansion space around the perimeter of your tiled room. No, the tile will not expand – but your walls do. If there is no space between your tile and walls it will force all the pressure into your tile. This will cause cracking grout and, eventually, ‘tenting’ of your tile.

You do not have expansion joints in your tile. For every application there are specific spans of tile which can be installed before a ‘soft joint’ is required. This is simply a grout joint filled with a matching caulk or silicone to allow for movement without cracking your grout or tenting your tile. Most of these measurements are over 25 feet. So in English: if your room is not 25 feet long or wide this is not the reason your grout is cracking.

If your tile is on concrete – directly on concrete – your slab may not have proper expansion joints or the tile installation did not honor those. If installing tile directly to concrete (and you should not) there needs to be a soft joint directly above, or two inches on either side, of the slabs expansion joints. If not your slab will move differently than your tile.

And there could be a host of other, less apparent or less common problems. However, if your grout is cracking it is probably for one of the reasons above. The method of repairing it depends entirely on why it is cracking. Most of it, as with most tile installation problems, is due to improper installation.

Or your pogo stick.

If you have any questions about the proper way to repair your tile or grout just leave a comment. I answer every one of them – really, look around the site. I’m just super cool like that.

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  • Laura

    We installed 1 x3 porcelain tiles (connected in a mat with glue dot like things between tiles) on a shower floor 3 weeks ago but didn’t grout yet. The shower is not in use yet. The tiles seemed secure until I was preparing to grout today & several tiles came loose, no thinset on the tiles. We tapped the tile with a grout float and wiggled them around, the thinset oozed between the tile (which was really annoying), and checked the backs of the tiles randomly to assure good coverage. so we’re wondering why the thinset didn’t adhere to some of them. We used schluter all set. How should we repair this so the tiles won’t have lippage? We’ve done other tile projects & always had good adherence & coverage.

  • Tiffany

    Hi! I recently had a bathroom remodel, in which we used marble 8×20 tile. It is beautiful, but I have noticed after a couple of months the tile is starting to crack right at the grout joints. Slight at first & then the line cracks all the way through. I am noticing a lot of slight cracks at this stage & I’m afraid this is a disaster.

    The contractor is looking into the issue this week. Any tips?

  • Jenny Grant

    Hi :) I own a mobile home. Had a flood in hall ball. It was gutted. Walls and floor all got new materials. Shower walls new hardie board and a coat of red guard. Tile was added directly to that. It was grouted 26 days ago. There are a lot of cracks in the grout and it happened right away. The guy who installed it has been installing for 20 years, I would hope you knows how to mix the grout. It’s a no sand grout. Could the cracking happen because it’s a mobile home and the foundation is not as solid as a home on the ground? Im also in southern California (small earthquakes occasionally) and I’m near an airforce base. We get a lot of sonic booms that shake our home. Thank you in advance.

  • Ken Sosne

    we have a white tile floor using 16″ tiles basic white done by a subcontractor for a rotten builder. I have one area where the grout seam has pulled away from the tile itself leaving a spaec of 1/8″ about 6″ long. The rest of the tile and grout seems fine. The company that installed the tile also sealed it for us. Can we leave it or is there a way to do a minor repair and watch the rest of the floor to see what happens. I know caulk is not great but can white caulk be pushed down to seal for the momemtn.

  • B Glass

    Tile in shower area is cracking. Do you have any suggestions as to why and how to fix it? It’s installed over concrete and liner.

  • Kathleen

    Is it usual to have tiles laid AFTER the kitchen is installed? My first floor flat built 13 years ago, bought from plans, has the grout in the kitchen almost non-existant. I have had all kinds of problems with settlement and all kinds of problems with builders of the flats. I got no solutions from any of them. However I can feel the floor moving under my feet, would I be better just giving up and getting some other type of flooring laid. I live alone and too old to do any DIY work myself now?

  • Alli

    We did a whole bathroom reno and replaced the floor with new plywood, had a contractor install schluter heating and put in porcelain tile, 24×24, a few months later the tile is clicking and grout cracking. the heated floor was not turned as it was summer when installed. it wasn’t turned on till months later, The contractor is upholding his agreement and replacing the floor. He does not want to reinstall the porcelain has fears will happen again. wants me to pick vinyl. What would be the reasoning behind this? He thinks the floor is the problem. From what i’m reading, installation… is there something I’m missing? can the fluctuation of heat affect the adhesive used on the tile? the affected tiles are the traffic area. I eagerly await your opinion

    • Douglas

      I meant to respond to you, but accidentally responded to Kat down below. I also responded to Elissa. I don’t think you want vinyl. Who wants a new bathroom with heated VINYL floors? It wasn’t the tile. It was the installation. Scroll down and read some of the other answers and you will understand. I am glad he is going to make this right, but it will still be a battle. For what it is worth, our installation was bad enough that they popped all the tiles right up and were able to reuse them – nothing stuck to the back because of the poor installation.

  • Denise Russo

    Hey how are you. In 2016 we had ceramic tile put in and over that time the grout had started coming up and one of the tiles cracked. They also replaced the subfloor at that time. We just had the tiles completely redone and they used wonderboard between the subfloor and tile. In a couple of areas the grout has come out slightly and on one of the tiles it makes a crunchy noise when you step on it. Any ideas?! Thank you

  • Jean Hartke

    I have a kitchen tile floor installed 5 years ago. The grout in major walkways has continuly cracked out. This has been dug out and replaced once and needs to be done again.The porevious flooring was also tile and lasted 15 years with no problems. I am wondering if this orange webbing has something to do with problem?

    • Roger

      Hi Jean,

      I have absolutely no idea what ‘orange webbing’ you may be speaking of. The problem with it is obviously improper installation, there is excess movement under your tile due to something. May be the substrate, may be the mortar mixed improperly, may be an improper substrate…it may be a LOT of things. To narrow it down I need to know what your tile is actually bonded to or over.

      • Neil

        Orange webbing probably refers to Schluter Ditra

  • Paula

    Hi, had bathroom redone about 7 yrs ago. After first year tile start to move and grout cracked in high traffic area. Basically in front of the sinks. I had the contractor come back and he said it must be MY subfloor that was causing the problem even though he was the contractor that had it installed. I argued the fact that it should have been fixed before floor laid but I got nowhere and decided to live with it until now. I got my hammer and siding bar and started uprooting tiles. The ones that were already loose came up easy. Ones closer to walls and tub took a little more effort to remove. From reading other posts and comments I was thinking maybe the mortar was too dry before they placed tiles or maybe it really is the subfloor? I still need to remove the mortar or whatever that white stuff is to see what that is on top of.

    • Roger

      Hi Paula,

      The number one cause of movement like that is actually inadequate prep. It may very well be YOUR subfloor, but the thing about that is it was HIS job to prepare your subfloor for a successful tile installation. If YOUR subfloor cause cracking grout, tiles, or any other issues, it means HE didn’t do HIS job.

      • Paula

        I agree, but I’m definitely not calling that guy back to fix it! I pulled up some then struck plywood so now going back and removing all down to the plywood. I’ll have to you tube how to go from there. Unless you can help me with that?

      • Paula

        I’m definitely not calling that guy back to fix it! I pulled up some then struck plywood so now going back and removing all down to the plywood. I’ll have to you tube how to go from there. Unless you can help me with that?

  • Elissa

    Hi, looking for some insight. We have a newly installed kitchen tile floor which has had issues with cracks in the grout since installation in July. We have tried different grout, reinstalled tiles but are still having issues. The current theory from our contractor is that the tiles are moving from The subfloor. We are desperately trying not too pull out the whole kitchen to replace the subfloor. Our contractor had recommended ceramic tile grout as this will allow for some flexibility. Is this a thing? Will this last? Thanks

    • Doug

      Elissa, in 2018 we had the same problem. New kitchen, new kitchen floor, grout cracking all over. Our problem, which might not be yours, was that none of the tiles actually adhered to the mortar. When they went to pop up a tile to see what was going on, it took 3 seconds to pry the entire 12×24 tile up. Eventually we decided to remove all the tiles and the mortar and redo (almost) everything. The cabinets were custom and the counters were stone and it was all too much trouble to take it all out, especially because no one has insurance against this sort of mistake. If they had left the water on and damaged everything, it might have been covered. So anyway, they removed the toe kicks from the cabinets and then pulled up all the tile, breaking some, but it was so loose that a lot actually slid out from underneath the cabinets. We had electric heat, and they had to chop that up and remove the mortar. The subfloor was fine, but they relaid concrete board down and then put all the tile back down. It is god-awful ugly under the cabinets and appliances, but you would never know from looking at it now. We still have no idea what they did wrong, though I suspect that the trainee mixing the stuff didn’t mix it correctly or, more likely, they should have back buttered all the tile to ensure that it adhered to the mortar.

      Ceramic grout came up, but it wasn’t the right solution, and it will mess up the tiles if you try to reuse them. It is more expensive too. They should try to pop up a tile – if it comes up easily, grout isn’t going to help at all!!

      • Roger

        Doug is correct, grout is not going to help at all.

        There are a few issues that could have cause the problem with the tile not bonding in this case.

        Improper mortar mixing, no backbutter, an excess of kiln-release on the back of the tile (the white streaks) or, most commonly, the mortar allowed to flash over before the tile was installed. This means that the mortar was spread, then allowed to sit too long before placing a tile over it causing the very top of the mortar to essentially ‘dry out’ before tile. This will hinder bond to the tile.
        If, when pulling a tile up, the mortar is bonded well to the substrate and not the tile – that is the issue 95% of the time.

    • Roger

      Hi Elissa,

      It sounds like it is an issue with the substrate. However(!) that is an issue that would have been dealt with during installation by using proper substrate materials and proper methods. If it’s an issue after the fact it indicates improper installation.
      Do you know how it was installed? Like what the tile substrate actually is – what he bonded the tile to?

  • Kat

    We have tile in our bathroom that was installed 2 years ago. It was a full bathroom reno and there is radiant heat under the tile on the floor. The grout is crumbling around the tiles and some tiles make a popping sounds when stepped on (clearly moving). Installer insists everything was done correctly but the image I have from before I left for work the day they did tile was that i believe plywood on the floor. Unless 1 man is able to do everything else with flooring im thinking they installed on top of plywood. It was 1 guy doing all the tile.
    They attempted to fix it by injecting something between the tile/under but it didn’t work. Now they are suggesting regrouping with silicone grout…..
    At a loss of what to do and what’s right to do

    • Roger

      Hi Kat,

      Do you have a heater vent or something in the floor that you can pull up and see if they did, indeed, install the tile directly to plywood? From what you’re describing that sounds like what happened, as that is exactly what will most likely happen by doing that. If they did, the only viable solution is tearing it out and starting over with a correct substrate. And yes – the installer is responsible for that, although the ability to recoup that cost will depend upon your local contractor laws.

    • Douglas Bank

      We had the same problem. New floor, electric heat mat, large porcelain tiles. None of the tiles stuck and grout was cracking within 6 months of installation. It probably would have cracked earlier if the rest of the kitchen had been finished earlier. It wasn’t the floor or the heat. It was a poor installation job where he didn’t back butter the tiles. He also used an older method of preparing the floor using a metal mesh and some kind of “concrete”. When they ripped it all out (which destroyed the heat mat and required a new one), he put down durarock instead, but I am sure that it was either the backbuttering or a better mixture of the mortar (and not using mortar to level the floor) that fixed the problem.