cracked porcelain floor tiles

[Kippee]

My renovated bathroom of 14 months suddenly developed a 44" long crack through 3 1/2 rectified porcelain floor tiles.

The subfloor is 3/4" plywood. My tiler used Flexsnap plastic grid, as recommended by Flextherm heating in place of durock, Mapei thin set ultra contact and installed Flextherm floor heating system. The tile is 17x17 rectified porcelain. The bathroom is on the second floor, the joists are 16" on center, "silent floor" tjI25. My home is 26 years old.

I would appreciate thoughts as to what could have caused it and how to address the problem--not just the symptom.

[Carbidetooth]

I'd wager you've got a support problem of some kind. Either deflection of subfloor/joists or movement along seam of underlayment. Linear cracks almost always point to some deficiency in substrate.


Can you pinpoint what of the above is in close proximity of crack?

The fix will be determined by the cause, but either way involves some demo to get to root of problem.

After quickly scanning installation instructions, it appears the Flexsnap is a heating element placement guide designed to be embedded in self leveler or thinset. What was the installation sequence?

[Tool Guy - Kg]

Welcome to the forum, Kippee.

What Peter asked. My first thought is that the crack aligns with a joist that has a 3/4" subfloor seam over it. But we'll wait to hear if you can supply some info.

[Kippee]

I am not sure if this is relevant, but the crack began right after the threshold of the entry to the bathroom. The quartz threshold did not crack.

The room under the bathroom is finished so I am not certain of the exact placement of the joists. (They do run from front to back of the house, as does the crack.) In the unfinished areas in the basement, a few joists are not exactly 16" on center. I did wonder where the joist placement is in relation to the crack. I will try to measure off the side of the house to get an approximation.

I do not know where the subfloor seams are.

Regarding the Flexsnap installation, my recollection is my tiler laid the grid over the 3/4" plywood subfloor, inserted the heating grid. He did use thinset.

I will take some measurements as to distance the crack is from the side wall of the house.

Thank you for your help.

[Tool Guy - Kg]

I think I remember reading that flextherm offers a 5 year warranty. If you were to call and open a complaint, it's typical that the company would come out to the jobsite to do some selective demo. I don't know what they would reimburse for, but they'll want to ensure their product was installed per directions before doing so.

Have you called your installer, yet?

[Kippee]

Thank you for all your responses and help.
There is a joist 75" in from the side of my home and the cracked tiles form a line 75" in as well. What might this indicate? I still do not know where the seams of the subfloor and flex snap are.

My tiler did look at it. His preference is to fill the cracks with silicone rather than remove the tiles.

[rmckee84]

Could be lack of fasteners if this is where a subfloor seam is. It's really tough to say.

Filling the crack with silicone is a lazy "solution". The right way to approach this would be to remove the broken tiles and demo until you can find the cause. Then fix it.

[cx]

Of course he does, Kippee. His tile installation failed and he doesn't want to accept responsibility for it. Putting silicone in the cracks is not even something you should give serious consideration.

Using that plastic mesh filled with thinset mortar over a single layer of plywood subflooring is akin to a Jersey Mud Job to my thinking and we know they fail more frequently than installations using industry accepted methods.

He owes you either an appropriate repair or a complete replacement of the installation.

My opinion; worth price charged.

[Tool Guy - Kg]

With the joist being located at the crack, there's a pretty good chance that the seam of the plywood is also there.

Imagine a new construction job site. It's got a bare plywood floor over the joists. And a seam in the plywood at the center joist (where your cracked tiles are). Now imagine that a baby elephant is straddling the seam. His left foot on the left side of that center joist/seam and his right foot on the right of the center joist/seam. Imagine how the plywood would bend down under his weight. Now....for the money shot...imagine what would happen to that seam. The plywood deflecting downward on each side of the seam would translate into the seams bending up (like a tiny volcano at the seam) and pulling apart. With this kind of movement, a brittle layer of tile doesn't stand a chance and simply cracks. I think that's what's happened. It's the big reason a second layer of plywood adds so much strength to the floor. The second layer does a lot to keep seams like this from translating into too much movement.

Does the crack exist for more than 4'? Perhaps the room isn't big enough to extend more than 4'.

As far as this:

Originally Posted by Kippee

My tiler did look at it. His preference is to fill the cracks with silicone rather than remove the tiles.

Yeah.... That's akin to a restaurant chef saying that he will gladly remove the offending dead rat from the cake you just ordered and smooth over the frosting. Not good enough. It's time to remove the broken tile, fix the underlying problem, and lay new tile.



EDIT: CX has the faster fingers today. Or perhaps I just talk too much.

[Kippee]

I do not intend to have the cracks filled with silicone. My tiler attributed the cracking to either settling or rain. Our home is 26 years old and we've been the only owners--no major settling in all these years and certainly not enough rain to cause this. (mid-Atlantic area)

While the crack is 4' now (it was originally a few inches shorter initially), the bathroom is 12 x 12. So, unfortunately, there is more room for additional cracking. No one regularly walks where the crack occurred because it is close to the door going into the bathroom. To walk on that space would result in our brushing against the bathroom door upon entering the bathroom.

Have any of you heard of this problem with Flexsnap before? Do you think I should contact Flextherm first or seek an independent evaluation? Can anyone recommend who could do an independent assessment?

I realize that removing any tiles could result in breaking the heating coils. Other than removing the all the tiles, the heating coils, thinnest and grid and laying durock or another layer of plywood atop the 3/4" subfloor (which is what I originally had wanted to do), then relaying the Flexsnap, Flextherm and tile for the whole floor, what options are there?

How do you recommend I proceed?

Thanks so much.

[cx]

Originally Posted by Kippee

Do you think I should contact Flextherm first or..........

Kippee, you should not be contacting anyone but the contractor to whom you wrote your checks. If one of the product manufacturers is suspected to be at fault here, your contractor should be the one to contact them and attempt to get some relief. If he did the installation in perfect compliance with the product manufacturers' recommendations, he may convince them to accept some liability, but don't count on it.

If you had a geographic location in your User Profile, you might find someone on this site who could give you a third-party evaluation of the problem. You might also visit the NTCA website and seek a referral there. Caution: Such evaluations are not usually inexpensive.

My opinion; worth price charged.

[Kman]

Originally Posted by kippee

My tiler attributed the cracking to either settling or rain.

So, rain causes tile to crack. That's good to know.

[Tool Guy - Kg]

Originally Posted by kippee

My tiler attributed the cracking to either settling or rain.

Anyways, back to reality...

The first clue that grabbed my attention (because it’s consistent with my theory of a 4’ plywood seam under the crack) is you measuring and surmising that there’s a joist directly under the crack.

The second clue is that the crack is 4’ long. This further supports my theory, as correctly installed subfloor will be installed in straight rows perpendicular to the joists, but the 4’ ends will be staggered, landing its seam on differing joists. In other words, the cracked tile isn’t likely to get longer as time goes on (due to the staggered seams).

Now, if you could project imaginary lines perpendicular from the ends of your crack and see that they are directly in line with the plywood rows (by perhaps looking in other parts of the house where you have visual access to the subfloor)...well, then....that would tie all three clues together and lend strong evidence that you’ve indeed got a plywood seam directly under the crack and excessive movement is likely the cause of the crack.

[evan1968]

Rain causing tile to crack

...come on now.

[puke]

If it rained for a few weeks...your joists would grow a bit due to humidity (not due to the rainwater itself)especially if it's an area that is usually dry. I don't think people understand how wood will grow and shrink a bit due to wood growing as it takes on humidity. Plywood is fairly stable,. and supposedly TJI's are also. But real 2x material grows and shinks readily depending on the humidity and temperature. I've never heard of it being blamed for tile cracks (except many (we are talking 35) years ago I was on a job in B.H. where they had hardwood set into a tile job along with travertine... Obviously, everybody was being an idiot trying to please the designer (which is NEVER a good recipe)...and it didn't even cross their mind to seal the back and all sides of the walnut with epoxy sealer before "setting" it.. I don't think that job was even finished before it went to hell. This was one of those jobs with 40 or so guys working on it,..and I was on something else entirely in a different wing of the house..and knew better than to open my mouth. But I did learn something that day that I didn't yet know. It surprised me as the years went by that there was nobody on that whole tile crew that knew that would happen.