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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Hello Roger,
We have a new build. We selected large rectified porcelain tiles (12x 24 for bathrooms and 18x 18 for kitchen. Right from the beginning the grout has been cracking and the tiles creak when we moved over it. The tile layer came back and pried out some tiles and regrouted them. I know he used backerboard and thin set during installtion. When he came back to reset it he used a different thinset and grout because he thought it would work better. it did not solve th problem and continues to crack and move. We have a laundry room on the first floor that has LG washer that vibrates during the spin cycle. The whole house feels the vibration and you can feel it in the floor joists. Do you think this could be making the floor or tiles move and causing the problem? Please advice.
Hey Joey,
The particular type of thinset and grout rarely have anything to do with it – it is all due to the installation method. When properly installed you can (literally) drive a forklift – or a Boeing 747 over it and it won’t crack. The washer is not to blame.
It really sounds to me as if he did not install thinset beneath the backerboard. If that’s the case then yes, the washer can work the floor loose enough to cause movement. The movement is causing the cracking grout, unbonded tile is causing the creaking (assuming it’s actually more of a ‘crunching’). If there is not thinset beneath the backerboard that floor will not remain bonded over the long-term, no matter what type of thinset and grout he uses under the tile. An installation is dependent upon the substrate – that begins at the plywood under the backer.
Hello Roger,
My neighbor and I installed a porcelin floor in my kitchen last October. I do have a few spots where the grout has cracked and come up. I do think that I have to pop up a few tiles to add more thinset. I also am wondering if a relatively dry grout mixture can be compounding my problem? I remember that this particular area was grouted with a pretty dry mixture. I was corrected quickly, but nontheless, it could be adding to my issue. I’m also wondering if there is any tricks to popping up the tiles? I’d like to try and reuse the exisitng tiles if possible.
Thanks.
Hey Jim,
Dry grout may be the cause, but it’s rare. More often than not it is either improperly bonded tile or a substrate which is not properly supported (no thinset beneath the backer). There is no way to remove tile which is properly bonded – it’ll come up in pieces. If it is not bonded well you may be able to pry it up with a screwdriver. You’ll likely need to replace the tile.
I am adding 1/2″ plywood over 5/8″ plywood and my screws are stripping before the heads pull down flush. Do I need a different screw ( I am using 1-1/4″ coarse thread drywall screws) or do I need to countersink. I would like to see more “bite”.
Hey Daniel,
You need a different screw – deck screws work well. The reason your drywall screws aren’t working is because they’re made for drywall.
Hello Roger,
Firstly, I would like to thank you for the information given re: grout cracking. Unfortunatley our floor has crack all over (grout I mean), well half of the house to be exact. At first it looked like it was just drying(the grout has a lot of rough look to it, bubble etc) I know that sounds weird but it’s true. We just thoght it was due to drying time etc. but recently one of the tile – the grout literally came off and in the kitchen area we hear alot of creaking sound when we walk … I am not sure whether that is normal at all. I am hoping it is just the improper grout mixing etc.
The contractor who we hired literallly disappeared! took all our money and did not finish the job that we paid him to do so frustrating, so we are left with a flooring that is now hanging on a balance whether we just take it all up and start all over. The contractor we hired then stated that our flooring (I think it was wood underneath if I am not mistaken) does not need a subfloor etc so he tiled straight onto the wood – I don’t know what kind sorry. The floor before the tile was a laminate flooring. So my question is, each time we walk around our kitchen area it creaks, what does that mean? does that have any relation to our grout cracking? In your professiona opinion … do we need to have the tiles taken up and start all over? I know it is hard to say but just your opinion would help. As for the contractor, he was long gone unfortunately. what ever repair we need to do we have to fork out the money ourselves and rectify the damage done.
Thank you so much
Maria
Hi Maria,
Unfortunately bonding the tile directly to wood is likely the cause of every problem you’re having with your installation. There is a method to tile over wood but it requires VERY specific methods, type of wood, spacing, etc. Nowhere in that specification are the words ‘existing wood’.
It sounded as if he just did the absolute minimum to make the floor look tiled and vanished.
The creaking, as well as the cracking grout, are a result of movement. the movement is because the tile was not initially bonded correctly or has become unbonded. Wood moves – always. Tiling directly to it without compensating for that movement it will break the bond between the thinset and substrate (wood). The only thing that will fix that is removing it and installing a proper substrate then tiling.
Hello Roger, I want to tile my floors, but I was wondering if I can do the tiling separately? I am going to use a decorative micro pebble around my spiral staircase and then a large tile on the floor. can I lay the decorative tile one week and grout, and then do the other tile later? I wanted to use the same grout. Will the edges of each section adhere to each other properly? I cant do it all at once I just dont have that much time.
Hi Melanie,
Yes, you can split up the installation however you need to. As long as you don’t walk on the tile until it cures for about a day then you’ll be fine. I would wait until you have all the tile set before grouting any of it. Some grout will blend well and some won’t. There are a lot of conditions that go into it.
Hi Roger,
We bought a new build about a year ago and have noticed over the past year that the grout in the hallway tiles is cracking and even some tiles have come completely loose. We initially thought it was the house settling. We had an inspector in last week who noticed that the joists under the hallway are 16″ centers, rather than the 12″ centers under the tiled kitchen floor and entryway. I have no idea what the builder has used under the tile, but I do know we have 1/2″ particle board subfloors screwed down, but not glued. We are trying to gather information so we are informed when they come to us with their fix options, so we know we are not accepting a “patch” rather than a real fix. Any information or suggestions you can provide would be very much appreciated.
Hi Kelly,
16″ centers are fine. If it is really particle board, and really 1/2″, those two factors right there are a very large part of the problem.
Particle board has no business anywhere near a tile installation at all, let alone beneath it. It is simply not structurally stable enough to support a tile installation. A properly build floor will have a 1 1/8″ double-layer PLYWOOD over the joists, then your tile substrate (backerboard, ditra, etc.). 1/2″ is nowhere near where it needs to be.
Unless there is, at the very minimum, an additional layer of real plywood over the particle board in addition to a proper tile substrate, it doesn’t matter what the joist structure is, that floor is simply improperly constructed. To tell you exactly what needs to be done, however, I would need to know exactly what layers you have beneath the tile. 16″ o.c. joists are what most structures (around here) have throughout – that is NOT the problem.
Do you have a heater vent in your floor you can pull out to see what layers you actually have beneath the tile?
Roger I looked closer and saw that the subfloor measurement is 5/8″ (15mm), but it doesn’t say on it what the material is, as I’ve just read about a material called OSB that looks a lot like particle board. So I could be mistaken on the material, although I have no way of checking.
I don’t know what happened to my previous reply, but its not there now. I looked in the vents in two areas and it seems only to be the subfloor (5/8″ either particle board or possibly OSB, not sure which as I just learned of this OSB material which apparently looks very like particle board), thinset, and tile. So there is definitely no plywood or backerboard under the tiles. Any suggestions you have would be very appreciated
Thank you for your time.
I switched servers this weekend so you were caught in the internet ether for a bit – it’s there now.
Sorry.
Oh.
OSB is ‘oriented strand board’. It is suitable for the first layer beneath your floor. It is a completely different product. Particle board is sawdust and small wood chips mixed with glue and pressed into a board. OSB is a layered, laminated board, still made of smaller pieces, but more like strands – in fact just like strands.
If you can get a look at the underside or maybe beneath a cabinet or somewhere a portion of one side of the board is exposed, the particle board will is a smooth, consistent appearance and the osb will vary in colors and shades of wood and you’ll likely see areas of football-shaped plugs.
If it is the osb then you can definitely leave that in place and just go over it with an additional layer of plywood, your substrate, then tile. As I stated above if it is actually particle board it will need to be removed.
Hi Roger,
We have underfloor heating and 60 sq metres of 60×60 tiles in our newly built extension, on plywood then under that weyrock new flooring. Tiling done in October last year, progressive cracking and lifting of grout, loosening of tiles and then one day an almighty crack, with a 2-3 metre length of tiles tenting up. Our builders have looked under the floor, all stable, and no signs of anything sinister happening in terms of construction/stability of the underlying joists etc. They are going to take up all the tiles, then relay using same cement, but this time with silicone perimeter and at least on line of silicone to allow for better expansion. Should this do the trick? Help!!
It should, because the reason for the first failure was likely lack of both soft joints and perimeter joints – both of which are required.
Hi Roger, thanks for the information about why the tiles seem to be cracking. Our kitchen tile floor seems to have certain spots where the cracking is most prevalent. There are some tiles that I can see moving in certain parts and hear the grout actually crunching underneath the pressure from walking. On the floor are about 150 – 180 13-inch tiles, and of those about 25 tiles have this grout cracking problem. The cracking has not spread to any other tiles but these, even after about 10 months with no grout between them. Since it does not seem to be a problem throughout the entire floor, but seems to be isolated to these 25 tiles (most of which are next to each other) which of these problems do you think it might be? If it is something that can be fixed at each tile, do you have any suggestions, or do you think that it is time to start shopping for new tiles? Thank you for any advice you can provide.
Hey Alex,
If it is in areas with grouped tiles it is either weak spots of some sort in the substrate or, more likely, areas where the installer was getting toward the end of a bucket of thinset and did not get a good bond. Take up one of those tiles and if it comes out whole and most of the thinset is only bonded to either just the tile or just the substrate then that is your problem. If so you can likely take up those tiles and reset them properly. If it is the substrate issue then you’ll need to replace the floor over a properly build substrate.
We had an addition done by a local contractor (who we cannot locate now) who installed tile in three rooms (2 baths and a sunroom). The grout in the bathrooms are crumbling away. After reading all your posts, I see that the correction will probably require a total re-do of the tile flooring in these rooms. I have no recourse with the contractor, it seems. Any suggestions besides suck it up and remove and re-tile the floors, completed by an expert in the field of tile installation? By the way, except for the sunroom (the tile is applied directly to a cement slab) all the grout is chipping away and has from the first weeks of installation.
Hi Belinda,
Unfortunately the tile in the bathrooms is likely having problems due to movement – which is due to improper installation. The only thing that will solve that is to retile them. Let me know where in the country you are and I’ll see if I know anyone in your area who can fix it properly for you.
Is the backer mat good I have used it and my grout is cracking out is that the reason
Hi Wayne,
Which specific backer mat are you speaking of? There are about twelve different ones.
What is the specific method of installing tile on wood sunfloor?
Hi Sara,
Do you mean wood subfloor? (you typed sunfloor) Specifically – don’t. Use a proper substrate to bond your tile, plywood isn’t it unless you’ve had a lot of experience with structures, framing, tile and a fair knowledge of how temperature, humidity and structural differentials affect a tile lamination.
If you want to I’m not disillusioned enough to think that will stop you, so use ab exterior grade plywood, leave 1/8″ gap between sheets, orient them perpendicular to the floor joists, offset them by 1/3 from the floor sheathing, fill the expansion gaps with silicone, leave 1/8″ to 1/4″ around the perimeter, use a highly modified, flexible thinset approved by the manufacturer for wood installation, backbutter every piece and wait a full 48 hours before walking on it. This is all, of course, providing that your floor structure meets the proper deflection requirements and has a 3/4″ sheathing layer properly fastened over the joists.
Then cross your fingers. Because those are just the BASICS, it is much more involved and intricate and EVERY installation is different and may require specific techniques I cannot begin to cover.
Ok thank you – as you can tell, I am trying to find ways around having all the tiles taken up. Sorry
No need to be sorry at all Ella, it’s completely understandable.
Hiya. Sorry to be a nuisance.
I was wondering, as they were put down only 14 days ago, could it just be shrinkage?
Hoping….E
If your tile is moving and clicking then no – it isn’t your grout shrinking.
We moved into our newly constructed home Oct 2010. We’ve so far had two tiles replaced with hairline cracks…just found the third. How common is this? Builder is coming back on March 19 to look at crack that just popped up on outer corner of foundation…having bit of a freak out moment after reading some posts online re tile cracking!!! What questions / concerns should we bring up with builder?
Hi Kristy,
Unfortunately it is extremely common. That, however, does not mean that it isn’t installed incorrectly. I would ask how (specifically) the floor was constructed, what layers of materials were used and, if cement backerboard was used, whether or not thinset was installed beneath it. It is usually a sign of movement indicative of an improper substrate.
Hi there.
We have just had our kitchen renovated. We had a wooden floor, varnished, in one part of it and a more hollow underneath wooden floor but solid wood, varnished , if that makes sense.
We had two different tilers look at it and both agreed it could be tiled over.
This was done a week ago using grey slate floor tiles.
We were told to brush and mop it to get up the dust, which we have. The tiles still are very dusty (well, it’s more stuck) and now we have noticed some of the grouting is shrinking (cracked?)
Help
Oh and today we noticed they “click” when walked on
Hi Ella,
Did they install the tile right to the wood? The ‘dust’ you are seeing is likely grout haze, it needs to be scrubbed off. The grout may be shrinking – did they use sanded or unsanded? If they installed the slate directly to the wood is it probably cracking due to movement rather than shrinking.
Hi there, not sure if my message sent earlier.
Two people agreed it could be put onto the wood floor, nothing was mentioned about it moving. What needs to be done? It cost a lot of money to have it tiled, so it should be right.
Thank you for your guidance
It it’s ‘clicking’ then your tile has become unbonded. Sticking the slate directly to the wood, especially two different wooden substrates, is not a proper procedure and will lead to exactly what you are experiencing right now. The only real way to fix it is to take it out, install a proper substrate such as cement backerboard or a sheet membrane such as ditra, and reinstall it with the proper bonding material. Sorry.
Your floor is going to continue to get worse if left as it is.
Oh bugger!
Thank you though
Sorry to be niaive but isn’t this something a builder should know? We had no idea and trusted what they said. It was only done a week ago, do you think he should come back and re do the floor. Thank you
You aren’t naive at all. Yes, your builder or contractor should absolutely know this! There are, however, way to many ‘professionals’ out there that don’t. Most cities and counties require a one year guarantee on contractor workmanship. If your work was done improperly (which it was) or there is a problem (which there is) they are required, by law, to take care of it. Call your local building department and find out what the particular laws are in your area, explain the situation and find out where to go from here. They can give you those answers.
Hi Roger,
How do we know for sure what he did or didn’t do? He put something on the floor first. I was out at work and when I got home was asked not to walk on them until the morning….fed up, as we paid a lot of money and feel let down and fed up of all the upheaval and mess. Even the tap isn’t straight and wobbles ( know that nothing to do with tiles – sorry)
You really don’t until it’s taken up and replaced. Unless you were there while they did it you’ll need to take his word for it. Whether or not the correct materials were used if the grout is cracking and the tile is clicking then something was done incorrectly.
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