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.
My house is six years old. I have had tile cracking from the first months I lived here. The builder replaced those tiles. A year ago my bathroom tiles cracked (3in a straight line). I had the builder come back. He said the house is settling. There is nothing he can do. I have no settling cracks on any Amy walls or ceilings. Now I find more cracks in my kitchen, again in a straight line. Is this normal? I’m 63 years old and have lived in several homes and never have come across this. Any advice?
Hi Helen,
It has absolutely nothing to do with your house ‘settling’. The cracking is normal if the substrate boards beneath your tile (cement backerboards if you’re lucky, and not simply plywood) are not fully supported or are improperly fastened. Cracks in a straight line are normally about three, four or five feet apart – that is the length and width of most backerboards. It is, simply, improper installation. It should be removed and properly installed, by your builder, since he’s responsible for the initial installation.
I apologize for the delayed response, you go shoved into the spam folder for some reason. Sorry about that, the elves who run the site are normally at least a little bit drunk when they do so.
I have one single 8″ long grout crack on a ceramic tile floor I installed about 1 year ago. I first noticed the crack a few months after the install. I removed a little bit of the cracked grout back then and re-grouted. The crack has returned. The tile floor is in the kitchen, about 12′ X 12′, 12″ ceramic tile with 3/16″ sanded grout. Subfloor is 3/4 plywood and I used Ditra as the underlayment. I followed installation directions carefully. I have a 3/8″ space along all walls. I used a Schluter transition strip in the doorway to the dining room. The dining rm floor is a floating wood laminate and there is 1/4 space between the two floors. The crack is in the middle of the door way, between the first and second tile. The crack runs parallel to the walls. There are NO other cracks. There are NO cracks at the Schluter transition strip. I did on occasion hear a “creak” noise when stepping on tiles near the crack. Wondering why I have a crack at this spot. Not sure if I may have stepped on the tiles too soon after the install. How do I go about repairing the crack? Should I take up all 4 tiles adjacent to the crack. Not sure which of the 4 tiles might be moving. Since I used ditra, do I also replace the ditra under the removed tiles. I checked the plywood subfloor seams and 16″ joist spacing in relation to the grout crack. The crack does lay close to a subfloor seam and is between the joists. Thanks for guidance on this issue.
Hi Jim,
It could be a number of things. My guess is that something has debonded the ditra from the tile under the crack, it may be the ditra debonded from the subfloor beneath the crack as well. Either way, something’s moving and we don’t want it doing that.
I would remove the four tiles you describe, as well as the ditra beneath them. Remove all the grout around the four tiles and use a razor knife to cut the ditra all the way through before removing the tiles. This essentially separates it from the rest of the floor so nothing else is damages or compromised while you do this.
As you remove the tile check each one (or the pieces of each) to see whether or not there was good adhesion to the underside of it. As you remove the ditra make sure there weren’t any hollow areas or spots that came up at some point which were not bonded completely to the subfloor. Once that’s removed walk around a bit and see if you can create that squeak again. If so then just drive some more screws through the subfloor to ensure it’s fully attached. Then install new ditra and replace your tiles. Doing all of that should take care of the problem no matter what was causing it. Keep an eye on it for a while, but it should be good at that point.
Roger, I pull up the 4 tiles adjacent to the grout crack. I found my problem. The plywood subfloor is weak at the area of the crack. It’s right at the corner of a section of the subfloor. Stepping on the subfloor in that area, I can see the plywood compress much more than it should. Lucky for me, I have good access under the subfloor from my basement. Was planning on stiffing up that spot with some 2″ X 8″ flat against the underside, wedged and fasten between the joists, with several deck screws through the subfloor into the 2″ X 8″. Do you have other suggestions for fixing a weak subfloor section from the underside?
Hey Jim,
Nope, you got it. Just make sure the 2×8 is snugged up really well and screw the piss out of the plywood.
Glad it was a fairly obvious solution.
There is one main crack that runs the length of the kitchen that is 20 plus feet long and then two short cracks that cross the hallway. One of them is probably 10 feet from the big crack and perpendicular to it and the othe one is probably 25 feet to the other side of the big crack and is parallel to the big crack. Most puzzling. I tapped on the tiles near the cracks and one or two sound like there is a void just under the corner nearest the crack. maybe it’s laid directly on the concrete slab and that is cracking?
Hi Meredith,
I would guess that those areas are tiled directly over a control (expansion) joint. Over control joints there should be a soft joint installed in the tile.
You nailed it exactly. I just had carpet removed in another room and there is a high spot that runs the width of the room along an expansion joint in the concrete. The installer dude is in there grinding it down to level right now. So two follow up questions:
1. Can I saw the grout out of the tile cracks and replace it with silicone grout caulk to make a functional soft joint?
2. I am having bamboo flooring installed in the other room and it was slated to be a glue-down application with the boards running perpendicular to the concrete expansion joint. The room is 16′ by 17′. Will this installation be okay?
1. Yes
2. Provided there is a crack-suppression membrane (like redgard) installed over the expansion joint it should be fine (I think, I’m not a wood guy – you may want to find a wood flooring forum for that particular question to get a more detailed or correct answer).
3. There is no number three…
Thanks Roger!
I was so bummed out about the cracks in my tile grout when I first saw them…it is a great relief to know that it can be fixed in a way that will last longer than the next change in weather. You rock!
There was a question #3, I just didn’t think of it until now. What’s the best tool to remove the old grout without damaging the tiles?
A grout saw. It’s a little hand tool that scrapes away the grout. You can find it at Home Depot.
Hi Roger,
Great site, great info! I just bought a house with a large expanse of floor tile. Kitchen plus hallway is 36 feet x 16 feet of uninterrupted tile, for example. The house is 11 years old and the tile and grout were perfect when we bought it. I had the tile floors and carpets professionally cleaned before we moved in, and immediately afterwards, I noticed grout cracks zigzaging along what would be a straight line if the tile weren’t set diagonally. Did the cleaning cause the cracks or just reveal a hidden fault line that would have cracked anyway?
Hi meredith,
It likely pulled either dirt or powdered (ground away) grout out of existing cracks. Are these zig-zagging straight cracks exactly (relatively) three or four feet apart? If so it’s likely cracking over the seams of the backerboards, if there are backerboards beneath it.
We recently had water damage from an overflowed sink in our bathroom which had 3 levels of water damage down to our basement. Two weeks later we have noticed cracked grout in the kitchen floor. There was standing water on this floor for hours and the basement ceiling beams was “raining”. Could this cracking be a result of the water damage? If so what could be causing it?
Hi Hayley,
It could be the beams drying out and warping which would cause movement in the floor above it. Essentially the underlying structure completely drying out and returning to it’s original form. Yes, it could cause cracking grout.
Hey Roger,
I have a house built in the late 1940’s it still has original tiles (wall and floo)
The floor tiles (approx. 1″ x 2″) are coming loose between the toilet and the tub. (The bathroom is only about 10×12′). The toilet was replaced a few years ago. I can fix this…right?
Hey Jay,
Yes, you should be able to remove the tiles and reset them with a good modified thinset. You likely have a mud deck beneath your tile – they are nearly bulletproof and last forever. The tile can be (and should be) bonded directly to it.
What if only some tiles are moving and causing grout to come up? Is there a way to fix that without replacing whole floor?
Hi Kate,
Sorry, you got shuffled into the spam folder for some reason. You aren’t a Nigerian prince wanting my bank information to deposit untold millions, are you?
It could be movement beneath your substrate due to not having thinset beneath your backerboard. That is the most common reason. You can remove those tiles, remove the backerboard under that area, install thinset beneath it and replace the backerboard and tile. It’s normally just an area which doesn’t have full support beneath the substrate.
I have a condo that was built in 2009 and the grout is cracking. The condo did sit empty for about 6 months. I had a repair person come out and say that it was because of the sub floor and I’d need to have all the tile pulled up and re-layed. I contacted the builder who had me talk to the company who installed the floor. They’re saying that it’s due to the time it sat without air conditioning/heating. They said they can re-grout but there’s no guarantee. Can going without air/heat cause the problem or was it more likely installed improperly? Thanks so much for your help!
Hi Jen,
It was installed improperly. A correctly installed installation can sit forever without heating or air conditioning. Tiled balconies and porches don’t have heat, right?
That’s why they told you ‘no guarantees’ – they know better.
I had a friend’s husband install tile in a small bathroom about two years ago. He put it directly onto the linoleum that was there before. Two years later there is one area of the tile where the grout is cracking big time. This area is between the toilet and the tub, which are very close together. That space gets more than its fair share of water drippage from the shower curtain and because I have a four year old boy who has been, uh, christening it on a daily basis as he learns to aim properly when using the toilet. The subfloor beneath the linoleum the tile was installed on is concrete.
Since the cracking is only happening in that one area, Is it possible the moisture from my shower and my son’s bad aim is causing it, or was it improperly installed to begin with?
Hi Ann,
Very possible. Most glues that bond linoleum are water soluble. Once water gets under the linoleum (or any ‘liquid’
) it will debond the linoleum and cause your tile and grout to move.
And yes, installing directly over linoleum is an improper installation.
Love your site! I have a quick question about cracks in my grout along a change of plane. The cracks are not wide, but are long- 4 to 6 inches in length and run where the floor meets the wall. What concerns me is that these cracks are continually wet. The shower has been dry now for at least 36 hours, and the crack is still very wet. When I dab it with a towel, the towel soaks up water, but more appears in the crack. It’s not enough water that it runs down to the drain, but it is enough to just sit… and sit… and (eek!) rot?!? whatever is underneath (lets hope its something waterproof- but at this point I’m guessing not. What do you suggest?
Hey Kenzie,
If it remains wet then your shower floor is likely waterproofed, it simply doesn’t have a proper preslope beneath the liner which allows water in the mud deck to drain to the weep holes. The grout should be removed and replaced with silicone, but ideally the shower floor should be replaced with a properly constructed mud deck.
Thanks so much for the quick reply! We’re going to remove the entire floor of the shower as you suggested. Seriously considering just going with a acrylic or some-other-type- shower floor so as not to run into the same problem again. I say that because the whole story is that the excessive moisture in the shower cracks has led to an infestation of drain fly larvae in my shower. It’s really beyond disgusting…
How long should I wait to seal my honed marble and grout? I want to seal it before the glass guys come in which puts me at about 2.5 days. My grout lines are just under 1/8″ and I used unsanded grout. Also, how long after grouting should I wait to take a shower? Thank you!
Hi Bobby,
24 hours for both.
I’ve got a problem with soft flakey grout. Builder has removed and regrouted twice after initial install. Grout was professionally tested and no problem. I’ve since had my own tile guy and do a test patch using non sanded grout. 72 hrs later it is still soft and can easily be scraped out without pressure. There are also Visible holes in areas. Because this has continued to happen, even with careful mixing, I’m thinking there could be a problem with the subfloor (?). Do you have any ideas? We also addressed the issue of old grout so purchased new each time.
Hi Melinda,
How large are your grout lines? Do you have hard water? Is the room in which it is being installed really humid? What type of grout are you using? If you are using polyblend – switch brands. If your grout lines are larger than 1/16″ switch to sanded grout. If you have hard water use distilled water. If it’s humid cover it with something like moving blankets after grouting.
We installed out tile over 8 months ago. We used all the proper measures when doing so. Over the past month Iv noticed our grout cracking and now when walking on some of the tiles a crunching sound. Wondering what it could possibly be as well as if this is something we just have to wait and see what could or could not be the issue
Hi Colleen,
I may be able to tell you why it’s cracking if you give me specific details of both HOW it’s cracking (in a straight line, in a specific area or all over, etc) and a detailed layer-by-layer of what you have beneath the tile from the joists up. Saying you used all the proper measures could honestly mean anything, there are over 40 ‘proper’ techniques of preparing a flooring substrate for tile. Also what type of thinset (specifically, brand and type) did you use.
Given that I could probably at least narrow down the possible causes for you.
So, we are preparing to lay tile on concrete. What do you recommend putting down first? We had our previous tile “tent up” and a portion even exploded loudly just like you described. I believe that there was no expansion at the edges as well as none in the middle of the 30 foot run from one end to the other. We are trying to avoid this tenting with our new tile.
There is a roll-on application. Would you use this?
Thanks
Hey Bryan,
It depends on what the roll on application is. If it’s an elastomeric membrane like redgard or hydroban then yes, I would use it. Ditra is also a good option. As long as you have perimeter joints and soft joints where required it won’t tent. That’s weird, though, isn’t it?
First time I heard one popped it scared the crap out of me.
Roger,
I have rental apartments. The kitchen ceilings always have leaks because
of the bathroom floor above. Which of your books would help me built
a bathroom that is as waterproof as possible?
Hi Butler,
No such thing as waterproof as possible, it’s either waterproof or it isn’t. As far as durability long-term and the ability of the shower to dry out faster (stays cleaner, lasts longer) you’ll want a topical membrane. I have two dealing with those, the liquid topical membranes like redgard and hydroban or the kerdi topical membrane. Of the two I prefer kerdi – it’s how I build 90% of my showers.
We have a terrible grout problem. It is falling apart! Here’s what we have: 2 layers of 5/8″ plywood, schluder ditra, 18 x 18″ porcelain tiles that are 3/8″ thick, and 1/16″ non-sanded grout lines. The floor joists were sistered with 3/4″ plywood which was glued and nailed. The floor has been down for 8 years now. It took a few years but then the grout started to break apart. It was slow at first and then became excessive. A year ago, we dug all the grout out of about half of the approximate 600′ area. We re-grouted it, and it is right back to where it was before digging out the grout. There are actually high-traffic areas with no grout left. There is a small bathroom that is only 8′ wide with 2 x 10″ joists that has breaking grout as well. We’re pretty sure that tile movement isn’t an issue there. Can you offer any suggestions for repairs? We are desperate for a solution. It’s tempting to try caulking at this point. Ripping the tile up would be a huge expense since the kitchen was completely redone when this tile was installed. By the way, we had a tile floor prior to this one with 8″ ceramic tiles and 1/4″ sanded grout lines with no problems over its 21-year life. My husband did that installation! He did watch the entire process of this installation and feels everything was done correctly.\
Thank You!
Hi Terry,
Are there perimeter joints or is the tile butted against the walls around the perimeter? Are there any soft joints at all? Either of those, done incorrectly, leaves you with an installation that has nowhere to relieve built-up tension from normal, seasonal expansion and contraction.
There are no soft joints anywhere but there’s no area that spans 25′. The worst area is in the middle of a 16′ span that runs cabinet to baseboard heat one direction and doorway to doorway in the opposite direction. There is about 3/8″ space at the cabinet where the toe space covers the space and the same at the baseboard side. The doorways have space covered by thresholds. My husband thinks that there still may be some bounce in the floor even though he did all that extra supporting. It certainly isn’t anything that I can feel.
Do you know what the unsupported span of the joists is? That is the area along the length of the joists between the vertical supports.
There’s 14′ from the center beam to the sill; 2x10s; 16″ on center; sistered with 3/4″ plywood that is glued and nailed.
With a 14′ span your deflection works out to roughly 380. The absolute minimum for ceramic or porcelain is 360. You may simply have too much bounce in the floor to support a 1/16″ grout line. That is very little grout, a thin line, to withstand any movement. The problem, somewhere, is movement in one form or another. With grout it is either abrasion – the floor tiles bouncing up and down as they are walked over, or compression – lack of expansion capability in the installation.
Given the size of your rooms and the expansion around the perimeter I would bet it is abrasion, which means your floor is moving. It may be lack of support or it may be the expansion or contraction of the plywood beneath the tile. Are the seams of the plywood (top layer) offset from the seams in the layer beneath it? And does the top layer lay perpendicular to the bottom layer? If it is not offset properly you may have enough support but the seams may be causing a cantilever effect as the space between the joists is stepped on. By chance are the cracked grout lines over or very close to the joists? Do they run in the same direction?
The seams of the plywood are offset but we don’t remember if the sheets of plywood are perpendicular. The best guess is that they are not. The cracks are both directions but where it got started is running in the same direction as the joists and, yes, they are close to the joists.
The cantilever would be my guess, then. You may be able to regrout with epoxy grout, which will withstand a lot more abrasion than normal grout, or you can try to install cross-bracing between the joists to minimize movement between the joists as the floor is walked on. Ideally those would run every 16″ as well.
Thank you. We’ll give both a try. Is epoxy grout readily available in stores and in colors (we need a bluish gray)? We haven’t heard of it.
Lowes normally carries laticrete spectralock, which is the best and easiest to use in my opinion. It is also very readily available online. I haven’t yet seen a tile I couldn’t match with one of their grouts.
We moved into a house with tile installed in the front hall–I think about 2003 and right in the center of the doorway from the hall into the family room, one grout joint continues to crack and fall out. I have replaced it several times, but it continues to crack and fall out. I surmise from your other answers I might be able to “grout” this one line with caulk. Do I buy a caulk the right color or mix caulk with some of the dry grout? Or is there another solution? I don’t have any more tiles.
Hi Jane,
The cracking you are describing is indicative of excess movement in the substrate. It would be my bet that particular grout line is right over a joist. You can use silicone, but it likely won’t last long either. Your best bet is to replace the entry tile. (You wanted new tile anyway
). There’s nothing you can really do to compensate for improper installation like that.
Hi Roger,
Here’s my situation. The previous owners of our home added an addition a few years before we bought the house, a portion of which includes a tile floor (12″ tiles). At the same time, they also replaced the floor in the existing kitchen with the same tile such that a continuous tile floor now runs from the kitchen to the far end of the addition – a length of about 25′. The kitchen is over a basement while the addition is over an unheated crawl space.
The portion of the tile floor in the addition (over the crawl space) is falling apart – loose tiles, cracking grout, etc – and each day it get worse. The kitchen side (over the basement) is fine. I’m not sure of the exact cause of the loose tile in the addition, but my bet it is a combination of factors (thermal, moving subfloor, poor thinset coverage, poor workmanship, etc). I did lift up a loose tile and there is cement backerboard.
Regardless of the cause(s), I’m fairly settled on replacing the tile floor with another flooring. Because the floor covers a kitchen, bathroom, and laundry room, we are considering sheet vinyl, vinyl plank, that sort of thing.
So my question is, if we tore up the tile floor and replaced it with vinyl – do we need to also replace the backerboard – or can we place an underlayment directly on the backboard? I realize this is not really a “tile question”, but I thought you might be able to help us.
Thanks in advance,
Matt
Hey Matt,
As long as you can get the thinset off of the backer and you have a smooth surface there shouldn’t be a problem with it. It sounds more like the joist structure beneath the addition does not have adequate deflection ratios to support a tile installation. It’s probably combined with other factors, but that may be the main cause.
Hi Roger,
I am considering a porcelain floor tile that is 17″ x 35″ and 3/8″ thick with 1/6″ grout joints. My existing subfloor is 3/4″ plywood over joists spanning 16″ o.c.. I think the joists are 2 x 10’s but I can find out. We are considering 1/2″ hardibacker over the existing subfloor, waterproofing with topical liquid and then tiling OR the schluter ditra system.
What is your recommedation for subfloor? Most importantly, I am wondering if we need another layer of plywood (3/8″?) before installing hardibacker or ditra? I prefer not to have to do this because we are connecting to a laminate floor in the adjacent room. And if our joists are only 2 x 8’s would this change your recommendation?
We have a 22 year old home. We tiled 3 floors directly to the original subfloor, no added layers when we built our house and have never had any problems with tile or grout cracking. We have 8 x 8 tiles though, nothing huge like we are considering for our current bathroom project.
Thank you very much,
Ruthie
Hi Ruthie,
Any proper floor construction requires two layers of plywood totalling 1 1/8″. Ideally you should have an additional 1/2″ layer over it, then your backer of membrane. Ditra would be better in that situation as it doesn’t add a lot of height. If you want to stick with just the current floor I would strongly recommend ditra over that then your tile.
My grout started cracking right after it was installed and has gotten progressively worse since then (< 6 months). One of our 24×24 porcelain tiles made a creaking sound when walked on a few weeks after install. Several tiles have since started to make a noise. We hired an inspector who removed a tile by hitting the center with a hammer and then used the claw to remove the tile. His observation was that the tile did not have 80% mortar coverage per ANSI 108.1. The tile was installed TCNA Method F112-09, Cement Mortar Bonded (white tiles, white thinset, grey mortar on soundproofing and then concrete subfloor — tall apartment building). My contractor and his inspector (the regional sales manager for the mortar/grout company) claim that there is 80% coverage. What I have observed is that there is some coverage of the white thinset used on the tile, but when the tile was removed, there was little or none of the grey mortar on the tile. The contractor fees that this is normal and that by removing the tile, the mortar “peeled off like a sticker.” Our inspector disagrees. My question for you is whether 80% mortar coverage means that 80% of the grey mortar is sticking to the tile when it is removed or that 80% of the tile is covered with the white thin set? Also, can the layers be peeled off or should they have been one unit? Finally, is it possible that a tile with this installation can make noise when walked on if it is installed properly? Also, note that the contractor’s inspector said that it’s common “in Mud Set installations such as this due to the grout settling into the deep grout joints created by this type of installation.” Is that accurate?
Hi Neil,
A mudset tile, properly installed, will lift up all of the thinset as well as a good chunk of the mudbed when removed. Mortar, again – properly installed, will not, ever, ‘peel off like a sticker’. So while the tile may have had 80% coverage on the tile it may not have had as much on the thinset-mortar junction. While a properly installed mud set tile may ‘sound’ hollow it rarely is. It should not, however, creak, move or sound ‘crunchy’. That is indicative of a layer somewhere in the lamination which is not properly bonded to the one above or below – normally the thinset to mud junction.
In short it sounds as if the tile itself had proper coverage but the thinset to mortar layer did not.
Thank you for the prompt response! What do you believe would be the cause for the thinset not bonding properly to the mortar layer? Also, what would the fix be for this issue? Finally, since our first “symptom” was the missing grout, I’d like your comment on the mortar manufacturer’s statement that it is common “in Mud Set installations such as this due to the grout settling into the deep grout joints created by this type of installation.” I’d really like to know whether our missing grout is related to the creaking issue (due to the lack of a proper bond between the thinset and the mortar) or if it could just be coincidental because it is a common issue (the grout came out both before and well after the 28 day cure period).
The grout issue does have to do with this type of installation but only when it is improperly done. Once the grout is cured it will not crack or crumble unless the tiles to which it is bonded move. Movement due to inadequate bonding slowly separated the grout from the tile. The constant movement slowly ground away the grout small bits at a time. The grout cracked and failed due to tile movement, not to the ‘depth’ of the grout line.
The fix depends on how much of the floor is improperly bonded. Areas that are need to be removed and replaced properly.
I had tile installed in my kitchen and hallway at the end of April beginning of May of this year. I had noticed a couple of hairline cracks in the grout, but now I have a couple of cracked tiles at the door jambs, and I have noticed a hairline crack extending north/south in the kitchen on two separate rows of tile. They are coming back to look at it, just wondering ahead of time what I should expect. The half bathroom area that was also tiled appears to be fine.
Thanks,
Kathy P.
Hi Kathy,
If it follows the normal issues your cracks are either three feet or five feet apart – yes? If so then it means the backerboard was not taped and mudded and/or there is no thinset beneath your backerboard. You did not mention what type, or if, there is backerboard as your substrate, but given the limited information I have that’s what I’d guess.
Is there a formula for grout between marble tiles outside on a partially covered deck in Florida? We have had cracks from the beginning. Installed about 6years ago. Thank you?
Hi Eirin,
I’m not too sure what you mean by a formula? If your tile is cracked it likely has nothing to do with the grout. Unless, of course, it is lack of grout lines and the tiles are butted against one another. Is that what you mean? If so the minimum acceptable grout line size is three times the variance of the tile size or a minimum of 1/8″.
Cracking in that type of installation is normally more indicative of an improper substrate or lack of soft joints.
i just had a tile shower surround installed in May (with a new tub). the tile goes from the tub to the ceiling. There are some long cracks around the tile where it meets the tub. any suggestions of why ? should i be concerned ?
Hi Susan,
Yup, it’s filled with grout rather than caulk. The tile and tub will move at different rates and in different directions with normal movement. Silicone can compensate for that movement – grout can not. Any corner or change of plane needs to be siliconed rather than caulked.
My kitchen tiles have been down for 20 yrs and have been fine, my ex husband did them and they are laid on concrete I have no idea if an expansion joint was laid above, I suspect he would not have known about this, the floor is about 20 ft long and has no gaps at the ends of the walls, they go right to the end. Now two or three tiles are not flat as they always have been, when I walk on them it appears ‘hilly’ and the grout has come out around one of them.
What do I do to fix this problem if the tiles are stuck down which I imagine they would be how can you get them up without damage? Or should I use spares that I have?
thanks
Hi Leigh,
The pressure may be building up in those tiles and causing the grout to crack. It is likely not yet enough to cause the tile to become completely unbonded, but it’s probably getting there. If you happen to be home when it happens – it sounds like a gunshot – seriously. It’ll scare the shit out of you.
You may be able to remove the grout out of the center of the installation and replace it with flexible silicone, but you will still need to create a perimeter gap at the ends. (And it’ll still be ‘hilly’) You may be able to remove them in one piece and you may not. It varies from installation to installation. I would plan on using the extras and if they come up in one piece it’s just a bonus. I never expect them to, though.
Roger,
I removed the 50 year-old mud bed and mosaic tile from my bathroom floor. There wasn’t traditional subflooring beneath it. Ledger boards(sistered to the joists) supported short 1×6’s running perpendicular to the joists, level with the top surface of the joist. To make a long story short, I’m down to my joists. I have 1 and 3/4 inches of depth between where I need the top surface of my new floor to be(to meet with an adjoining floor) and the top of my joists.
What is your recommended combination and thicknesses of subfloor and cement backer board? Tongue and groove ply? Advantech? Hardie? Durock? My joists are 2×8’s, 16oc, spanning 99 inches. I’m laying 12×24 porcelain approximately 3/8’s thick.
Thanks in advance!
– Jonathan
Forgot to mention self-leveling cement.
In that case one 3/4″ layer, one 1/2″ layer and 1/4″ of SLC. Or one 3/4″, one 1/2″ and ditra.
Hey Jonathon,
Two layers of 1/2″ ply and one layer of 1/2″ backer. With thinset and tile that should get you right where you need to be.
Your floor was built that way in order to accommodate the thickness of the mud bed. It was common practice and still a recommended method in certain applications.