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.
Hi! Do you know if heated bathroom floors might cause the grout to crack with the expanding and contracting? The house isn’t even two years old, the grout has been fixed once already and has cracked again. Improper installation is probably to blame since I think drunk monkeys could have done a better job building this house! Thanks!!
Hi Melanie,
It could, but properly installed it won’t. It could also have been turned on prematurely (at least seven days after the tile is set) which will cause the thinset to prematurely cure and weakens it considerably.
we had tile reinstalled in our kitchen recently and the grout is cracked in many places. one tile has cracked. the contractor is going to replace the cracked tle. if we dont fix the cracked grout, what is the worst case scenario? will more tiles crack? will grout flake off? thanks.
Hi Karina,
More tile will crack, grout will crack, flack off or turn to chunks and come out. If the tile is cracking it is either inadequate bonding, substrate or an improper installation technique. None of which are fixed by simply fixing the cracked tiles. There is a larger issue beneath the tile.
Tiles in hall way next to the stairs make noise if you walk on them.
Hi Madhu,
That means that the tile is becoming unbonded and the sound you hear is the loose thinset beneath the tile grinding against the bottom of the tile as you walk on them.
Roger,
I had tile installed in my bathroom 5 months ago. My house is 12 years old. The installer used the backerboard and the grout is 1/4 inch. Last month I noticed thin line cracks alongthe edge of the tile in 4 different places within the bathroom. One is in the middle front of the vanity, one is in front of the shower, one in in the doorway going into the toilet closet, one is in front of the tub area. They are spaced out and all are staight lines along the edge of the tile like it’s pulling away. What will we have to do to fix this?
Hi Carol,
It sounds like the backer seams were not taped and mudded. The only way to repair that is to remove the tile and prepare a correct substrate before installing tile.
I bought a home 2 yrs ago. The tiles in the kitchen floor are cracking at the subfloor joints. Both along the floor joists and perpendicular to them. 1/2″ plywood subfloor ran perpendicular to floor plywood, about 3″ from seams. There is a 1/4″ gap between subfloor sheets filled with thinset. Subfloor is screwed every 6″ and 3″ at edges. I removed some tile and subfloor to install hardwood which gave me insight to how it was installed. When I eventually tear out the tiles will a membrane be sufficient to prevent cracking ? Tearing out subfloor is nasty hard work but if its what has to be done I’ll do it. would rather pay for membrane. Your input would be greatly appreciated.
Hi George,
Is the tile bonded directly to the plywood??? If so then yes, a membrane should be more than sufficient for you.
I am very concerned about the noises in my house (Not Ghosts). Very Loud cracking noises in the front wall of my house. And when I walk close to the Bathroom sink the floor tiles clack.The Bathroom is next to the Back wall of my house. Who would I call to check these things out? Thank you for any help or advice you can give me
Hi,
It is likely tile popping loose (sounds like a muffled gunshot) from lack of expansion or perimeter joints. When there are no expansion joints present the pressure will build up over time in the tile installation and eventually build enough pressure to pop the tiles loose. Any reputable tile contractor can take a look at it for you and tell you what needs to be done.
Thank you for such a great sight. To Angela I would like to add that it could be a foundation problem. Look at your basement walls, walls and ceilings for cracks. Have you if doors and windows close harder than before? When looking for cracks…if the crack is wider at the top indicates a structural problem and everything will start to shift in your house.
My son that has worked construction for many years, gave me a wonderful Mother’s Day present. He retiled my kitchen floor for me. Ok, he works in framing, so this is not his primary like of work. Now to the problem. All is fine, except one tile in the center of the floor. on one corner, when you walk on it, you can feel it is a little spongy, and now the grout has worked out and he (we) don’t know how to fix it. Any suggestions other than removing the whole tile? These are 18″ tiles with very small grout lines. Please don’t say remove the tile…..
Hi Joan,
Okay, I won’t say it (but I will type it – sorry). The only way to fix improper bonding of a tile is to remove it and replace it properly.
I find lot of hairline cracks in plaster at joints between the beam and brickwork in one of my newly built building. kindly let me know the reason.
Hi Manas,
I have absolutely no idea at all. I’m a tile guy, not a plaster guy.
Hello
I was reading all the reasons for cracking grout lines and was wondering why my grout is just cracking on the surface of the lines I used a grout sealer and it looks like just where the sealer sunk in it is chipping out and under that the grout seems to be fine, could you tell me whats going on and the best way to repair and solve this problem?
thanks so much.
Kevin.
Hi Kevin,
If you mean that it is cracking off in layers (???) that is indicative of improper mixing of the grout. It will need to be removed and replaced. I don’t believe the sealer has anything to do with it unless you installed it before the grout cured.
Hi Roger,
it is really cool of you to answer every comment on this site. I recently had my kitchen tiled. There is a plywood subfloor and the previous floor covering was linoleum. Originally I had discussed with the installer putting in cement backerboard, but my counter height was not tall enough to allow for the backerboard, the tile and the dishwasher. So together we decided to use redGard as an underlayment. However, my contractor came back with SpiderWeb2 decoupling mat. It is thin and the dishwasher barely fit back into place after the tile was laid.
After they grouted the floor, they used my dolly to put the dishwasher, washing machine and dryer back in place in the tiled laundry room. They finished about 4 pm and told me I could walk on it that evening. Since they had already moved heavy appliances across it and they said I could walk on it, I did. It started to flake that evening, 4 hours after they left. My contractor blamed a bad batch of grout, then they put new grout over old. I didnt pay much attention to their method, but the extra grout really made the floor look bad, thick, wavy lines, going on top of the tile, rounding off some of the tiles’ corners. Then it started to flake again. Now my contractor is telling me it must be the underlayment and advised me to sue the manufacturer, Custom Building Products. (The tiles are not moving, and the underlayment is supposed to decouple so flexing sloors shouldnt be a problem). He does not want to be responsible for either regrouting the whole floor, or completing any more repairs. Without looking at it, could you suggest to me a cause?
Thank you very much,
Edie
Sorry, I wanted to add that the grout WAS sanded, and the majority of the flaking is in the high traffic area of my kitchen, a lot of it in a straight line. But the contractor did put thinset under the undlerlayment and did use seam tape, then another layer of thinset. Again this type of underlayment is supposed to accomodate flex in the floor by decoupling, and my contractor said he has seen floors with a lot more movement that did not have this grout flaking problem. I just need to know what I should do, after spending thousands of dollars on what I thought was an improvement. He said regrout the entire floor with epoxy grout but it would be very hard to find someone to do this, he wont.
Edie
Again, this type of underlayment is NOT supposed to accommodate flex in the floor. And if your contractor told you that he’s seen it in floors with more flex he’s full of shit. Epoxy won’t work either, your floor is improperly built – period.
I’m a disabled veteran on alot of medications, so my brain is on vacation most of the time….About 3 years ago my shower was modified to remove a “trip hazard” by removing the acrylic one piece and it was replaced with slate tiles and graduated drain in the back of the shower.
I’ve been informed that there is water under the house (from the shower) and there are cracks in the sanded grout and it must be uninstalled/reinstalled to correct. Because of mold/moisture issues I need to ensure that the damage is minimized, so I need to move forward and resolve the issue before serious structure damage occurs.
Which of the following seems the be the most appropriate to correct leak and resolve all problems I’m leaning towards one, but want some in put just to make sure.
One contractor says he can possibly reuse the bedpan (will depend on how much is damage during demolition….He said that its possible that he might be able to reuse the bedpan (he did check under the house but made no reference to the leak)…and that he needs to paint something on the backboard in a green color to prevent moisture damage before tiling. He also referenced using a grout that wasn’t sounded/unsanded or epoxy and it was pre mixed and no sealing ever would be needed.
Another contractor said that I needed a special water proofing system that was the “Schultz” (I could be wrong but defiantly started with an “S” that had a 10 yr warranty and needed “certification” to install and the company has special classes and test for this product…a new custom bedpan is needed and then the materials that only they can get with the same manufacture…(reports not sold at home improvement store)…and then epoxy grouting
Another one says that backer board with mudding the seams and screws would be sufficient, a new custom bath pan….and then using unsanded grout with a sealant of grout and tiles after drying at least 3 days before it should be used.
Which of these seems to be the one that will resolve the issue and get it fixed?
Thank you for your time…
Hi Kathy,
None of them sound complete to me.
1. If your shower is leaking the pan liner is likely compromised in some manner. I would NEVER reuse a liner from a shower that is being replaced The green stuff is likely hydroban, and that’s great for the walls, but doesn’t solve the floor issue. The floor needs to be completely rebuilt with new products, not used. The grout is likely a urethane grout, which may or may not be fine in a shower. It depends on the brand. And they all require AT LEAST seven full days to cure before water exposure.
2. I have no idea what ‘schultz’ may be. If it was schluter, that’s a great system, but is hardly proprietary and does not require certification to install it. It is available at big box stores and to the public in general. If it is schluter then he’s blowing smoke up your ass in an attempt to make themselves look better/more educated/needed? I dunno. And the type of grout has absolutely nothing at all to do with the waterproofness of your shower.
3. That is fine for the walls. And a new pan (properly constructed) would be fine for the floor. But again – the type of grout has absolutely nothing at all to do with the waterproofness of a shower. The use of sanded or unsanded grout is dictated by the size of the grout lines – that’s it, nothing else. Sealer also has absolutely nothing to do with the waterproofness of your shower. It is for maintenance purposes, not waterproofing purposes.
Hi Eddie,
Someone does not understand what an uncoupling membrane does. It compensates for IN-PLANE movement, NOT flexing floors. It is not a proper replacement for correct substrate preparation. Your floor was obviously not built well enough to handle a tile installation, it need PROPER preparation. Installing an uncoupling mat hoping to fix improper support means your contractor does not know how nor why they work. He is wrong, not Custom Building Products. Flexing floor require preparation to make them NOT flex.
Our two bathrooms are fully tiled with 300x600mm tiles floor and wall. The house is 2 years old. In both bathrooms hairline cracks have appeared in the grout next to a couple of tiles and the tiles starting to lift a couple of mm. The lastest one is next to the toilet. This is on the third floor of the building in both cases. Can you guess at the cause? What should I do to fix it? Is it shoddy workmanship?
Hi Angela,
It most likely is shoddy workmanship in some manner. Either not properly preparing the substrate or not getting the correct bond coverage beneath the tile. It is not the tile, it is the installer.
Hello Roger,
I have a few tiles in my kitchen that have some movement to them, causing some of the grout around them to crack. I suspect the cause is due to cracked thinset. Is there a way that I can repair the thinset or otherwise reinforce it without breaking the tile? I don’t have any replacement tiles lying around and am not sure where the original installer purchased them.
Thanks,
Gary
Hi Gary,
There’s no real way to do that without removing the tile. You may be able to remove the grout and inject an epoxy into the grout line around the edges of the tile. Depending on the cause of the movement that may or may not work.
So we have a large kitchen and mudroom above a finished basement in a new construction home with 12×12 tiles. The subfloor is Oriented Strand Board with sheets of plywood on top. There is some sort of thinset on top of the plywood but I don’t know what type. While still under warrenty, within the first year, we have had to have the subcontractor come out and repair these hairline cracks in the grout lines running several tiles long and in both directions. The cracks start small and over a month start to get so bad that we are vacuuming up large chunks of grout. They are also occurring in one half of the kitchen/mudroom area, while there are also some portions of the other half that appear to be very powdery, like we can scrape them up with our fingers. We have had the subcontractor out to fix these 4 times and every time they say none of the tiles are loose and this is normal due to the house settling or too much humidity. So they grind out the cracking grout and re grout it. Then it cracks again in a few months, always in the same spots and sometimes in additional spots and we have to do the whole thing over again.
Questions:
-Are they right about the cause?
-Should we just let them continue to come out and implement the same fix indefinitely?
-Is there a way to objectively determine if a tile is loose other than their opinion?
-Do you have any recommendations about what we can do about this?
Thanks for your help,
Danny
Hi Danny,
1. No, they are not right about the cause. ‘House settling’ is bullshit in regards to tile installation unless you live in a piered house over an ocean, and humidity has nothing at all to do with cured grout. No you should not let them keep doing the same thing.
2. Yes, but it requires removing the tile to determine the coverage and bonding of the thinset to both the tile and substrate.
3. The solution depends on the cause. The lack of bond or proper coverage is one possibility, which requires removal and replacement. Since it’s in the same areas consistently I lean toward the cause being either improper substrate support for the given installation, or improper installation of the layers of substrate beneath the tile. The tiles can be well bonded to the substrate, but if the substrate is moving it’s going to crack your grout.
We recently had 4 separate areas of tiling done in our rehab home. The kitchen, which is the largest area, already is showing micro cracks in the grout. And by micro, I mean I only noticed them when I was about a foot away. It is only happening there and not to the other areas. Also, the cracks are only happening at intersecting joints, not on the sides. The particulars are:
2×10 floor joists cross braced 16″ o.c.
3/4″ plywood (real stuff not osb)
3/8 particle board over the 3/4 (was already there from previous floor)
1/2″ durock set with thinset using 1/4″ square notched trowel
1/2″ durock then screwed down with 1-5/8″ rockon screws while thinset was still wet
All seams taped with thinset and anti – alkali tape
All tiles are 12×12 porcelain with 1/4″ lines
Used sanded Polyblend on all.
The other 3 areas all used the same color and the kitchen was a different one. I’m wondering if maybe the batch was mixed too thin and there is shrinkage? Any input would be greatly appreciated as I am looking for another professionals opinion before I contact the installer.
Thanks again.
Josh
Hi Josh,
It could be a couple of things. The first would be the fact that there is particle board beneath your backer. Particle board compresses as weight it placed upon it, then it springs back (almost). Multiple compressions lead to an indentation in the particle board. It doesn’t matter that you have thinset beneath your backer if the substrate beneath it is not solid and/or is compressible. It could also be the mixing and shrinking of the grout, polyblend is horrible in my opinion.
HI, SOME OF THE GROUT IN MY BATHROOM FLOOR TILES LOOKS LIKE SOMETHING IS EATING THROUGH IT AND ITS PROTRUDING ABOVE THE GROUT LINE IN A CRUMBLE STATE. IF THIS IS SOME TYPE OF INSECT HOW DO I KILL IT? wE HAVE UNDERFLOOR HEATING AND PORCELAIN TILES WHICH WERE LAID WITH FLEXIBLE ADHESIVE AND FLEXIBLE GROUT.
Hi Thomasina,
I have no idea. It could be (literally) hundreds of different things. Unless you can identify what is ‘eating’ through your grout I can’t begin to tell you how to eliminate it.
Hi There, I have a concern and am looking for a reasonable answer, I’m at wits end. About a year and a half ago I had my tile removed and almost my whole house retiled. The old tile had been in approx 12 years, no issues, tile was just old and we wanted to remove carpet. The job was beautiful. We have a concrete slab and tile over it. This was using regular grout from a bag. About 6 months later grout was coming out and in traffic areas looked marbled and little pits just coming out. Contractor repaired the areas and came back in 3 weeks to seal it and it looked the same again, all blotchier and marbled looking. He took the grout out of the whole house and came back with epoxy grout, it once again looked gorgeous and within 6 months it is coming out and all marbled blotchie looking again. Thin-set was the only thing that was under the tile. I know in one area where it is really bad, there is a huge crack in the floor that the previous contractor filled in prior to the tile job 12 years ago, when that tile was removed there was no sign of moisture everything was dry and powdery, i do not believe there to be a moisture problem is why i bring this up, we had no grout issues with the tile they removed just the new installed tile and grout. What would cause two different types of grout to do this? This is a reputable contractor and I do trust him but we are looking at a redo again. I did bathrooms, shower and the majority of my 2000 sq ft home and parts of it look like I did it myself and I ashamed of it. Please advise.
Hi Carol,
It sounds like there are no soft joints or perimeter joints in your installation. Pressure will build up from regular seasonal movement and cause the entire installation to expand and contract. That pressure releases at the weakest point, normally the grout. It may also be lack of complete or adequate coverage of thinset causing an incomplete bond, which allows your tile to move as it’s walked upon. Start by asking about expansion or soft joints and perimeter joints.
Hi Roger, thank you for the reply. In further investigation we are noticing the floor has several uneven tiles, tenting in areas. The grout company came out to take samples but since this is the second time with different grout, I am not expecting it to be the grout but rather the preparation of the floor as you have indicated as a possibility. Our contractor wants to do a moisture test to remove him as responsible basically as we found out that he is pretty sure that he did not reseal the crack when removing the old tile. WE see no signs of moisture and neither did they when putting down the tile. He stated that he will not do another repair without the moisture test and that if it comes back to not be moisture, he is stumped as to what could be the problem. I do see that it is butted up to the walls in most area with out any soft joints. Is it possible also that he just did not allow enough cure time? This has been ongoing for 2 years .
It is lack of expansion and perimeter joints. The pressure build-up will sheer the bond of the thinset beneath the tile. I highly doubt that it is moisture.
My house was restumped over a year ago. Shortly after we gutted and renovated the kitchen which included new everything like subway tiled splashback and fresh plaster. We recently gutted and replaced the bathroom which includes 600x600mm floor to ceiling tiles. At the same time the tiler did the kitchen floor. After a couple of weeks the grout has started to crack and crumble mostly in traffic areas especially the shower floor. The tiler believes it’s mmovement but no signs are shown in any other room. I believe the grout has areas of shrinkage along with poor curing. What do you think?
Hi Christopher,
Did he use sanded or non-sanded grout? If non-sanded then it’s likely just shrinking rather than movement.
The tiler said non sanded with an additive. The floor and walls were grouted on separate days and only the floor is poor. I’m finding it hard to believe it’s movement when no where else in the house is showing signs.
Roger,
Thank you for your website. It has allowed me to ask some very pointed questions of my contractor about why my kitchen floor tile grout is cracking. I’m wondering how you would fix a tiled kitchen floor if you knew that there was no joist blocking, no thinset between the substrate and backerboard and no crack isolation membrane installed before the floor was tiled with 12″x24″ rectified porcelain tiles? My contractor’s solution is to pull and replace two tiles that have the biggest problems with cracked grout with some kind of super duper adhesive (there are other areas of cracking), then grind out all of the grout and replace it with some kind of super duper grout. I told him that if the floor is flexing, then there isn’t any grout in the world that won’t crack, but maybe I’m wrong (I really hope I’m wrong because he said the next solution would be to pull the entire floor). If he pulls the entire floor, is my only option a crack isolation membrane? We can’t get at the entire underside of the floor because there’s a finished basement beneath the kitchen. Thank you.
That is not the only solution at all. Any proper substrate which allows for the deflection ratio of your particular floor will work just fine. However, if your floor does not meet the minimum deflection requirements it will need to be properly shored up before tile is installed over it. Your contractor should know how to measure for that and compensate for it if needed. Which takes us to your first question – why would they do it if they know. They may not know.
It’s evident that he either didn’t know or think about the deflection. What is the chance that their proposed fix for the floor will work, in your opinion? Is that what you would do if you were asked to fix this mistake?
It depends on whether it’s cracking due to an insufficient substrate or something else. I would take the whole thing out if it were mine to fix.
Hi Roger,
In my den, the tile tented, then tile went down. Felt a bit crunchy when walked on but that’s all. This is the first time I lived in a house on cement foundation. House was recived in will, no idea who put down the floor, ws there when my son bought it a few months before he was killed at work March, 08 . I have only been in here two years. We had a pretty heafty rain as of late, the tile tented, popped now the grout is cracked, but dry. Who would you recommend I go to for help & repair? What is going on? House is all tile and I am afraid of what’s to come. Really would welcome good advice!!! Thank you.
Hi Patricia,
It would be my bet that there are no soft joints or perimeter joints in the installation. Wood (wall framing) and concrete move at different rates, soft and perimeter joints compensate for built-up pressure caused by that. When there are none, and the tile is against the walls without space, that pressure has to release somewhere, it’s normally right in the middle of an installation (as you now know). Any reputable tile contractor should be able to help you out. You may be able to have the loose ones replaced and have soft joints installed throughout the installation. That would likely solve your problem provided the entire installation is not compromised.
I just tiled a small powder room floor. The first day I tiled it and the next morning I grouted it. All was well so I thought, my friend who I did this for later that evening tried to steam clean the floor (shark steam cleaner). Later that night he calls me and says the grout started coming out and some tiles popped up. The underlayment of the floor was concrete. I think the problem was the grout was too fresh and not cured enough. He thinks it has something to do with the tile moving. Normally I would agree however, not all the tile is moving just a few, but the majority of the grout is.
Hi Mark,
It’s the grout. I have no idea why the tile came up, they obviously weren’t properly bonded to begin with. Any cementitious product requires a full 28 day cure before infusing moisture into it. Steam cleaning should not be done until it’s down and competed for a month.
That is what I thought for the grout, when I went over to choke him I looked at the tile and none were loose. However a lot of the grout was bad, I cut it out and re-grouted.
Thank you, Just wanted to reconfirm my thoughts.
Mark
I just tiled my shower walls a few days ago – I used a premixed sanded grout and some of the grout is cracking. The largest seam is 1/2 inch but most are smaller. Since the grout is only a few days old – is there a way I can fix this?
Don
Hi Don,
The absolute largest grout line you can use that type of grout in is 1/4″ – and that’s pushing it. It shrinks, that’s why it shouldn’t be used there. The only proper way to fix it is to remove that grout and replace it with powdered sanded grout you mix with water.
Hi Roger,
I have a slab in my backyard (about 200 sq feet) that I want to tile.
Here are a few images:
http://www.wuza.net/upload/13913.jpg
http://www.wuza.net/upload/13914.jpg
It is pretty level already and there are a few cracks that I plan to fill with some cement. I am really on a budget (remodeled already half the house in the last 6 months – including tiling the kitchen on top of cement boards)
I have a few questions where your input would be greatly appreciated:
– Do you think I can tile directly on top of the slab (it doesn’t seem to move anymore – 40 years old slab) or must I use ditra (ditra would be the same price as the tile I plan to install…)?
– The edges of the slab are not straight (wavy line) and I have two choices:
– Cut the edge tiles with a diamond cutting tool with a cruved line following the slab border (my guess is that I would waste a lot of tiles…)
– Rent a concrete saw to make the slab rectangular (seems easier and would fix the wavy border that I didn’t like anyways)
Thank you for your help,
Regards,
John
Hi John,
You either need ditra or another crack isolation or uncoupling membrane. Filling those cracks with cement will not alleviate the stress point, it’s already done that. All that will do is give it something else to crack in the same area. If you don’t like the wavy get rid of the wavy.
I would, I don’t like it either.
Hi Roger,
Thank you for your answer.
At the Lowes next to my place they only sell Mapei thinset. Do you recommand Modified or unmodified thinset:
– Between the concrete and ditra ?
– Between the ditra and the tile ?
Should I fill the cracks with cement first or just the thinset I put between the concrete and ditra will be enough to hold the tiles?
Thank you,
John
Unmodified for both. You should fill the cracks, but with silicone. You want to prevent thinset from getting into the cracks, it will lead to it cracking out as I described, which may lead to problems over that area.
Hi Roger. Thank you, and the sub flooring is plywood. I’m wondering how much give it has… We’ll look into these possibilities. Again, thank you!
Hi Roger,
My husband installed some tile and grouted it three days ago. The grout is cracking in some spots, and we do not know the cause. The tile was put down using 3/8″ of thin set, and the grout lines are a 1/4″. The grout was mixed exactly the same way he always mixes it (toothpaste consistency), and he’s never had a problem with grout cracking before. He did another room a couple weeks ago, and it has had no problem (I should note that the other room is chilly and empty, this room with the cracking is fully heated and sees lots of foot traffic). Both rooms have wooden sub flooring also… Any idea what the cause could be and how to fix it? Any input would be greatly appreciated! Thank you.
Hi Lynn,
It could be an inadequate subfloor (you didn’t mention what’s under the tile), improper type of grout (unsanded rather than sanded) or grout shrinking from too much water added.