# help! why do the tiles in my bathroom crack?



## Bud Cline (Mar 12, 2006)

Has nothing to do with the tile. The substrate is not suitable for tile.

Sounds like Texas! 

Are the cracks at different elevations from side to side?

Is your slab a "post-tension" slab?

There are ways to accomodate some of this problem but they may not be totally effective in all cases.

What type of soil is around your home?



> Are you in:
> Adams
> Hempstead
> Bridgehampton
> ...


Describe the landscaping.

What is the elevation of your home in relation to other homes in the neighborhood?


----------



## diy'er on LI (Jul 6, 2009)

coming from the tile guru, that's depressing news 

what's a post-tension slab? The home has a partial basement (under the eat-in kitchen)... the dining, living, and family rooms are all on slab.

well, it's a large home and foyar... I think the tiled foyar is something like 50' by 20'? there are no cracks except for this one.

The front yard is a reaonably large hill (with the home on the top of the hill), and the backyard has numerous slopes.... with an overall very slight slope towards the house (we're regrating next year so we can flatten it out, budget permitting). The home to the left of us is a bit higher than us and the one to the right is a bit lower (both fairly far away... over 100 feet)

the soil is fairly clay-ish, but we never have pooling water anywhere in the yard. We live in the center of western suffolk county.....

Do you think there's any way to work around this problem so we may still have the gorgeous porcelain tiles we picked out (didn't place order yet)?

oh, and I have to go check the tiles in daylight to see if the cracked halves are at different elevations. upon initial inspection, I think they're not. they're only cracked.


----------



## Bud Cline (Mar 12, 2006)

HOLD ON NOW, it's not the end of the world just yet!!!

OK, based on your "partial basement" comment it isn't likely you have a post-tension slab so we can eliminate that as an issue.

Living on a hill helps some but keep in mind your landscaping has everything to do with the health of your structure. It is most important to keep water away from the foundation. You need to get rid of any gradation that slopes towards the house.

Now since you know your soil is clay we can start there. I was hoping that wasn't the case. Clay is like a sponge. It absorbs water easily and when it does it expands with great forces. It is safe to assume that may be the cause of the crack to begin with. Water coming towards the foundation surrounded by clayey soil isn't good.

I'll bet if you correct the drainage issues you will stop the slab movement for the most part.

Now the tile.

There are isolation membranes that will allow the slab to move under the tile to some degree. They will even allow that crack to open and close slightly with the seasons if it is still a living crack and from the sounds of things it is alive and well. There are also flexible tile adhesives that will accommodate some movement.

The biggest thing right now is the question you didn't answer.
Is the crack the same elevation on both sides of the crack or is one side higher than the other side? If the slab is moving up and down you're sunk for now. If the slab is only moving laterally when the crack opens and closes you may be OK with a membrane.:yes:


----------



## nap (Dec 4, 2007)

I am not trying to step on buds toes. I am definitely not a tile guru but anyway:

if the crack is not different elevations on each side, it is better than if one side has risen or the other lowered.



bud; where is am working, they are laying quite large tiles (up to 2 ft X 3 Ft I think, maybe bigger). They rolled on a black rubbery coating before mud and the tile. They told me it is used to isolate the tiles so they would not move with the floor and you should not have the cracking problems becuase when laying a tile over a crack, the tile is not adhered to the floor so tightly as to cause the tile to split when trying to follow both sides of the crack.

I haven't seen it before (but I am not a tile setter so it could be a million years old) but the theory makes sense to me.


----------



## cocobolo (Dec 16, 2008)

By your description of the crack, it almost certainly seems not to be the fault of the tiles.
You mention clay, this possibly has something to do with the cause of the cracking. 
It is entirely possible that the concrete beneath your existing tiles has cracked, and is moving just enough to crack your tiles.
It may be related to a drainage problem around the house, wherein water is getting under the slab somehow during the rainy season - if you have one - and possibly expanding the clay a small amount. Then shrinking again in the dry season. That's purely a guess.
How old is the house?
Have you asked your neighbors if any of them have a similar problem?
Since this seems to be a recurring problem, it appears that you will need to do as much checking as you can into that slab.
Is there any possibiity that you have a plumbing leak which is introducing water onto, or immediately beneath the slab anywhere near that area?
Things to think about anyway.


----------



## cocobolo (Dec 16, 2008)

Sorry about that - I was writing while the last two posts were being put up!


----------



## diy'er on LI (Jul 6, 2009)

right now, I'll say that from your descriptions I *think* it's a lateral shift... I will post an update tomorrow. The lighting isn't very good down there, and I don't really trust my "feel-around blindly" diagonistic.... but it doesn't seem to be different heights.

and this problem entirely COULD be due to the clay soil  (hate that freakin' clay and my hilly yard! We're definitely regrating... either next summer, or the following year... it will be a HUGE expense and a giant mess for sure.)

At any rate, the home was built by my family in the mid 70's. (that's why I know the history so well :wink 

What should we be looking for when we demo the floor (and finally see the slab for the first time in 27 years)? I'm presuming there's a crack in the slab? 

I entered tile heaven today....our local porcelanosa store... we picked out 1'x1' porcelain tiles... that company recommends installation with their own thinset/grout... I'm definitely not going to 2nd guess the company. I'm hoping that doesn't conflict with any possible solutions you tile folk suggest!

thanks so much for your input once again!


----------



## diy'er on LI (Jul 6, 2009)

UPDATE

my husband looked at it this morning... he thinks one side of the crack IS higher than the other... sigh... I'll look at it again this evening when I return from work.

we decided that since we're laying the tiles ourselves, we'll demo the old floor well before we relay the tiles so we assess the slab situation in more detail... Don't know what we should be looking for though.

When I figure out how to post pics, I'll put 2 up...


----------



## cocobolo (Dec 16, 2008)

I thought of something else last night while I was trying to sleep.
Since the crack appears to be in a straight line, I wonder if you perhaps have a drain line, (or perhaps an electrical line in conduit, less likely) that has caused a weakness in the concrete?
To post a picture, scroll down when you are doing your post to "manage attachments"
Click on, then click "browse", select your photo from your computer,
click upload. Wait a few seconds it will load. Close the window, go back to submit reply & click.
Your picture should be there.
You will need to size it to 100kb or less first.
And one other thing about your tile laying exercise (check with a tile whiz on this) I think it is schuler-ditra (spelling??) that has the orange colored substrate for tiling. It separates the tiles from your concrete - or other sub floor, helping to avoid the problems you have.
I believe the romans used to set tile on a bed of sand which had the same effect. And many of their tile jobs are still intact!


----------



## diy'er on LI (Jul 6, 2009)

thanks... I didn't realize the manage attachment option was down there. I was looking above the message area....

the top picture is of the tile in the bathroom. the bottom pic is of the bathroom door leading into the hallway (hall is top of pic)


----------



## cocobolo (Dec 16, 2008)

Well, those cracks are remarkably straight.
One other small thing. I am going to lay some of those terra cotta tiles myself here, and of course they are quite thick.
When I mentioned the schuler-ditra (spelling again??) I should have noted that you may, or may not, have a problem with the overall thickness.
Your porcelain tiles may be only 1/4" or so thick. My terra cotta tiles are around 9/16" to 5/8", yours are likely the same.
So if you use the S.D. underlayment, your overall thickness may remain very similar.
Or, you could use regular cement board as well, which might help to alleviate the problem.
Not sure about that, better ask the experts.


----------



## diy'er on LI (Jul 6, 2009)

I'm at work, so I don't have the sample tile in front of me, but you're right, it's not that thick. Right now, I'll guestimate it's 1/4". (wierdly, our wall tile is thicker than the floor tile... likely 5/8") The terra cotta is definitely thick. It's the handmade variety, so it is lumpy, bumpy, and likely 3/4". Due to the variability in the tiles, I wouldn't be surprised if the mortar beneath them is also thicker than it will be with the new tiles.


----------



## cocobolo (Dec 16, 2008)

I am led to believe that the bulk of the Terra Cotta tile comes from the Guadalahara area of Mexico. And I believe it is all handmade, hence the variations and bumps etc.
Being a soft tile, it does not have the strength of porcelain, not by a long shot.
Now get back to work!


----------



## diy'er on LI (Jul 6, 2009)

cocobolo said:


> I am led to believe that the bulk of the Terra Cotta tile comes from the Guadalahara area of Mexico. And I believe it is all handmade, hence the variations and bumps etc.
> Being a soft tile, it does not have the strength of porcelain, not by a long shot.
> Now get back to work!


very true...

yeah, I really have to prep a pile of slides now... no more tile talk till evening :whistling2:


----------



## buletbob (May 9, 2008)

I would agree that the crack is in the slab also. could there be any waste lines or heat / water lines under the slab in this area. is the bathroom in the middle of the house. there should be a haunch under the slab down the center of the house and if so does the crack stop at the center or does it continue on past? I cant beleive the builder poured the slab over the clay soil with out removing it. But then again I have seen plenty of sobby work here on the Island.BOB.


----------



## diy'er on LI (Jul 6, 2009)

I don't *think* the slab was layed incorrectly... merely because it's in very good shape everywhere else. After 35 years, I presume a myriad of problems would have developed if there was an improper installation.

now that you mention it, there very well MAY be a waste pipe under the floor. I am fairly certain the waste lines in the home ultimately run due south (towards the partial basement). On the opposite side of the north wall of this bathroom, there's another bathroom. Therefore, the waste lines likely run either directly under this bathroom's doorway, or parallel to it.

Ditto for hot/cold water lines... which would run due north (from the partial basement to these 2 baths). Think we might have a leak? What would the signs be on the slab if we did? I presume the leak wouldn't be bad enough to actually moisten the concrete.


----------



## nap (Dec 4, 2007)

not necessarily a leak. In fact, probably not. The pipes are a void in the concrete so where they are is a weak spot in the concrete and more prone to cracking.


----------



## diy'er on LI (Jul 6, 2009)

You wouldn't think it, but it's so difficult to determine whether the 2 sides of these tiles are different heights. 

We used a level this morning. We think it's higher on the east side of the crack, but with the tiles being so rustic, curved, and irregular, it really is hard to tell. If it is 2 different heights, the difference is 1mm or less.

what do you think about possibly putting cement board down, a ditra membrane then the tile? The new tile is roughly a 1/4 inch thick. Do you think that may isolate the floor sufficiently from any seasonal movement? Or is the ditra on top of the cement board needless overkill? Would that make the bathroom floor way too high relative to the terra cotta?


----------



## nap (Dec 4, 2007)

you won't be able to tell if the crack is not level until you remove the tile. The tiles should show the uneveness but part of the tile could also simply be becoming detached from the thinset.


----------



## diy'er on LI (Jul 6, 2009)

that's true. I'll stop my tile microanalysis :whistling2:


----------



## Bud Cline (Mar 12, 2006)

Let's back up again.

After seeing that crack (it isn't at all what I expected) I'm not convinced the slab has a crack.

Here's something you can do right now. Pull the baseboards around the room and see if the tile is grouted tight to the walls. There should be a gap at the walls under the baseboard. But, if the tile is grouted to the walls there is a strong possibility that that is your problem. 

In addition to checking at the walls, use a hammer handle or screwdeiver handle or wooden broomstick and tap on the tiles in the center of the room. See if you get a solid report or a hollow report. Tap each and every tile and listen for a difference in the sound.

Personally I like that tile the way it is. The crack adds charm. You could grind and tool the crack to turn it into a work of art creating a vine with leafs and offshoots.:thumbup:


----------



## diy'er on LI (Jul 6, 2009)

now that you mention it, I have told my husband that I think I sense a hollow feeling with the tile that is the worst cracked. 

I will definitely pull the moulding off and give it a looksy. I'm hoping the floor is pressed right against the wall. That would be a VERY good. (I've read a lot online about the causes of cracking tiles over the last couple of weeks. The one thing none of the sites tells you is what the cracks look like with each of the causes... So, I'm an educated clueless person... the most dangerous type of DIY'er! :laughing

I would be soooo happy if the slab were intact under there!

yeah, we're sort of sad to see the floor go in that room. The tile is gorgeous (in the hall, there's even a tile with a wolf or dog foot print!). We're fine with the hallway crack and will leave the majority of tile as is. However, the bathroom will be completely gutted of it's yellow, brass, and floral-ness and made ultramodern... so the terra cotta wouldn't go that well anyway.


----------



## Bud Cline (Mar 12, 2006)

There is a condition in tile installations (failing tile installations) known as "tenting".

Tenting of the tile occurs when the tile is grouted tightly to the surrounding walls. When mother nature attempts to expand the tile it must have a place to go. Thus the gap at the perimeter is required. When there is no gap and the tile is tight to the wall or grout has filled the gap the tiles will lift without warning. This lifting generally first occurs somewhere near the center of the tiled area but not always. There have been reports of tiles exploding upward from their installed position. There are plenty of photographs on the Internet that show a tile floor that looks like a bomb has gone off and there is rubble from the tiles ejecting themselves from the floor.

Tap the tiles and see if they report hollow.

I have walked on tented floors that showed no real destruction of the tiles. The floor would move downward as you walked on it. Everything was still in tact for the time being.

Those cracks (to me) don't look like something caused by the substrate cracking. They look like stress cracks within the tile units themselves.


----------



## Bud Cline (Mar 12, 2006)

Footprints in Mexican type tile isn't really unusual. The old fashion Mexican tiles were sun-baked and I suppose some still are. These tiles are/were made by families and then sold to the government who in turn markets the tiles worldwide. When the tiles were cast they were set aside out of doors to bake in the sun. During the curing process any animal could come along and walk on the freshly cast tiles. Chicken footprints are actually the most popular.

The truth is...once the Mexican tile makers realized there was a market for the imperfect tiles with the animal tracks they began purposly producing such tiles and they weren't imperfect at all. There's a story in tiledom about all the Mexicans that tie a chickens foot to a stick and use it to make the impressons on a mass-production basis. I've heard you can in fact order Mexican tiles with animal tracks in them.

Years ago I worked in Texas where Mexican Saltillo tile is very popular. Those were the years when the odd tracks would show up in an order from time to time. Some customers wanted us to use the tiles and others would have us cull them for disposal.


----------



## diy'er on LI (Jul 6, 2009)

too funny... chickens on a leash. Well, we're suckers. we like our dog/wolf footprint. So did our tile guy. he asked us if he could keep the 'imperfect' tile :laughing: since there was only 1 in over 88 sq ft of tile, I bet ours is accidental... at least that's the story we're going with :thumbup:

by the way, we didn't take the trim from the wall, but I did inspect the area under the baseboard, and the tile wasn't against the wall (but the crack doesn't reach that wall). Upon closer inspection, he DID tile right against the edges of the door frame (and the crack runs straight through it). I always thought the frame should start above the floor? but then again, my presumptions could be totally wrong.


----------



## jpcustoms (Sep 26, 2009)

*cracked up tile*

do the hollow test on the tiles around the crack, tap with your knuckles or screwdriver handle and listen. loose tiles sound hollow. go around the entire room and may can see a pattern. i'd rip up the tile, scrape the floor and then use a fortified leveler and skim the slab. then use the new durock tile membrane with their adhesive and cover the entire area. you do have a slab problem, but durock claims this is a crack free system, so give it a shot


----------



## Bud Cline (Mar 12, 2006)

If the above is a reference to Custom's "Easy Mat" - Forget it.


----------



## yummy mummy (Sep 11, 2006)

Hi Bud ...........tile guru? I like that. Yes you are....:wink:


----------



## Daniel Holzman (Mar 10, 2009)

This is an interesting, fairly common case. I used to do forensic investigations on structural damage, and I looked at about half a dozen tile failure problems in the southeast.

In cases where the slab has seriously cracked, you are most likely to get a large crack in the tile. Specifically, what you have appears to be a non-displaced hairline crack. The next size up in the world of cracks is a crack approximately the size of a credit card. You are nowhere close to that, so I discount the theory that the slab is significantly cracked. By the way, all concrete slabs crack, the issue is how much, and how significantly, they are cracked. At this point, I would say there is no evidence that your tile crack is due to slab failure.

I observed two cases where a "tenting" type failure, as noted by Bud Cline, had occurred. In both cases, there was an obvious hollow zone in the center of the floor. The tiles had literally detached from the thinset. In one case, the failure was traced to an improperly mixed batch of thinset, which had not properly adhered to the tile. In the other case, the failure was traced to dimensional changes in the house itself due to moisture changes, resulting in stress to the tiles because there was no relief gap along the edges of the tile. The result was failure of the tile at the center.

In one other case I examined, several tiles cracked because water had leaked onto the floor, and had remained there for several days. Apparently the water caused dimensional changes to the grout, leading the tile failure in a localized area. The apparent cause of the failure was that the grout was stronger than the tile, thus when the grout expanded, rather than cracking the grout, the tile cracked.

I don't see any evidence of slab failure in your case. Due to the length of the crack, and the linear nature, there may be a pipe of some sort embedded within the slab. 

I like the use of Ditramat as a bond breaker between the slab and the tile, it certainly is a good product and will minimize the potential for future cracking, but may not eliminate the potential entirely. There are other products that purport to act as bond breakers, however I am not familiar with them, and cannot comment on their effectiveness.


----------



## jpcustoms (Sep 26, 2009)

Bud Cline said:


> If the above is a reference to Custom's "Easy Mat" - Forget it.


 nope, not easy may. durock membrane


----------



## diy'er on LI (Jul 6, 2009)

you rock.... thanks so much for your input. Becuase of everyone's recommendations, I will definitely put in a ditra mat... and I'm much more hopeful that the crack is not due to a major slab issue.

I'm sort of envious of your job.... I think I missed my calling. More interesting than labwork... You solve difficult problems and aren't stuck in the same room day after day! then again, physics was never my strong point, so I likely wouldn't be a very good engineer... but I digress...

thanks again.....




Daniel Holzman said:


> This is an interesting, fairly common case. I used to do forensic investigations on structural damage, and I looked at about half a dozen tile failure problems in the southeast.
> 
> In cases where the slab has seriously cracked, you are most likely to get a large crack in the tile. Specifically, what you have appears to be a non-displaced hairline crack. The next size up in the world of cracks is a crack approximately the size of a credit card. You are nowhere close to that, so I discount the theory that the slab is significantly cracked. By the way, all concrete slabs crack, the issue is how much, and how significantly, they are cracked. At this point, I would say there is no evidence that your tile crack is due to slab failure.
> 
> ...


----------



## Bud Cline (Mar 12, 2006)

> nope, not easy may. durock membrane


OK then.......

Does this miracle product have a name of its own and if so...what might that name be?

Jesus, I should have been a dentist.


----------



## Bud Cline (Mar 12, 2006)

NEVERMIND...I found it. Never heard of it before, Reminds me of Tavy Thin Skin with its secret formula "007 sauce".

Just another isolation membrane flooding the market. If it's anything like the rest of their products it should be a good one.

JUST REMEMBER!!!!! Those membranes work only if the movement is lateral. If the movement is up and down they offer nothing.

Does that $1.59 per square foot include the adhesive?

http://www.dtm4me.com/?s_kwcid=TC|16363|durock%20membrane||S|b|3055685876


----------



## diy'er on LI (Jul 6, 2009)

Just wanted to update...

Our tiles were finally delivered last week, and we demo'ed the floor last weekend. there is no crack in the slab. The cracking was restricted to the tiles, as predicted by several posters. We're relieved. We're putting in a ditra mat before installing our porcelain tile floor. 

It's all very exciting  

thanks for all of your input!


----------



## Bud Cline (Mar 12, 2006)

Good news.

Your worries should be over.


----------

