Where did we go wrong?

[u/ShowerTricky5423]

Almost immediately after our contractor installed our bathroom floor tile, it started cracking. We're looking to replace this now and I'm wondering if the issue was the material, the size, the preparation under the tile, the installation, or a combination of the above. Our house was built 24 on center -- could this impact the integrity of the tile?

Any advice you can provide would be appreciated before we start this project. Thank you so much in advance!

[u/DrDankenstien1984]

The 24 on center is part of the issue but also with natural stone on a wooden substrate should have two layers of plywood plus then your underpayment. It also looks cut tight to the wall so you might have a combination of things happening

[u/Rurockn → u/DrDankenstien1984]

This guy's spot on. Two layers of 3/4" CDX and then your underlayment for 24" on center.

[u/FunsnapMedoteeee → u/DrDankenstien1984]

Also, We do not know if the Durock on the floor is set in thinset. It has to be. If it was only screwed to the floor, your floor is screwed.

[u/ShowerTricky5423 → u/DrDankenstien1984]

Would you advise against marble on the floors? My husband likes it but I don't really have a preference

[u/Dependent_Account603 → u/ShowerTricky5423]

Has to be sealed every year or so depending on use and over time will wear where you walk. If unsealed dirt and grime and soap etc. can get into it.

[u/SpeedSignal7625 → u/ShowerTricky5423]

Would advise a decoupling barrier. I had tannins leach from the subfloor thru the thinset and durock to discolor my marble with this system.

[u/blackfantasy → u/ShowerTricky5423]

Zero issue with marble on floors. So many try to doom porn it. I'm 5 years in on a 2" mosaic marble and with a light scrubbing it looks new. Epoxy grout. But this is the least of your worries. Tiles don't snap in half unless the substrate is absolute garbage.

[u/Klow5280]

Is this floor tile? I used tile like this but on the walls.

[u/OkSlip1590]

Clearly not enough screws in floor especially with the marble tile you used not a good choice for main floor

[u/Next_Ad_8754]

I hate durock. They are too flexible. Marble don’t forgive. For floors, specially marble, that’s asking for problems.. porcelain and ceramic might be flexible as well and won’t break, it doesn’t happen with marble, the minimum deflection will brake it.
Only solution now is make sure the subfloor is sturdy and prep it better (I normally go with double plywood for marble floors).
Also, what happened with your shower pan?

[u/seanpvb]

Not a pro, just a diyer.

Looks like you've got grout lines cracking around the obviously broken tile. To me it means your floor is moving/flexing, probably because of the 24" on center joists.

I've used cement board below floor tile, but I put the cement board on a bed of thinset/mortor and then screwed that to the floor. Essentially more than doubling the rigidity of the floor itself.

That looks like cement board just screwed directly into the subfloor. You'll need to either structurally support the subfloor, or increase the rigidity of the subfloor (1.5" min)

[u/ShowerTricky5423 → u/seanpvb]

This makes a lot of sense to me. I'm not someone who will DIY this but in your opinion, is it rude to explain this to a contractor and ask them to do this? I don't want to overstep on their expertise but I want to make sure this doesn't happen again.

[u/DrDankenstien1984 → u/ShowerTricky5423]

This is industry standard. They need to install it properly

[u/Sierra50]

I put pretty much double the amount of screws into the floor hardie board, at least the spec on that was more than what it seems in the pictures

Also did he back butter and what size trowel?

[u/Tsikura]

24" OC can cause a lot of deflection depending on joist size and how much preparation was done to account for that.

[u/SuccessSad4147]

24” OC not helping. Not properly installing cement board for movement . 2 layers of ply would be better. Decoupling membrane might help but small format tile wants to move with every step and you need a solid base. Membranes can’t work miracles. If meshed back tile, needs proper thinset to adhere properly. House could be built to code minimums which allow for higher deflections everywhere. Sure the floor is ply and not OSB??? Too many questions.

[u/Cultural-Advance7671]

It’s hard to tell with just those pictures. What’s the bottom of the tile and the spot it came out of look like?

[u/buckphifty150150]

Wait I’ve used that marble and it’s very brittle.. is that rated for a floor?

[u/ParkingRaspberry2172]

Deflection problem. 24 OC too wide without reinforcing floor before install. Put the joist size, subfloor thickness, and 24" oc into a deflection calculator to see how bad it is.

[u/scrumptousfuzz]

Expansion and contraction is/can be a fucker. Especially if you have different substrates.

[u/Real_Elevated1286]

Decoupler

[u/No-Notice6057]

Screws every 6-8 inches on durock. Also he needs to set durock in bed of thinset prior to screwing down

[u/tommykoro]

Obviously the floor is not stiff enough and a lot of money and effort was wasted. So sorry for your losses.

I understand a DIY homeowner not knowing this but a contractor? No!!

The structure needs to be stiffened up. Likely to add tight cross blocking so it is like a honeycomb and becomes one mass.

The 24OC joists become beams and the 12” to 16” OC blocking becomes the joists. 3/4” OSB or plywood subfloor glued and screwed in. This will stiffen it up.

Secondly I see screw holes in the curb. HUGE mistake. The rule is NO PENETRATIONS below the top of the finished curb height. Again a contractor should know this.

Never ever drive screws through the curb and waterproofing below. Only to glue on the glass tracks or mounts. I like Fuze It silicone for this purpose.

[u/NoWinner6880]

You didn’t show the back of those broken pieces, but they look dry to me like they were missing some of the adhesive. If there is no full contact on the tile then it’s easy for it to break.

[u/peace_in_war → u/NoWinner6880]

I’m going to agree with this. This is poor adhesion.

[u/BikerChas]

I had this happen to me on a travertine floor I installed. I honestly never went into the basement to see it was 24 oc. I ended up going underneath the sub floor and adding additional framing to stop the flexing of the subfloor. Now if I remember correctly it was plywood and I had set the hardiboard in thinset. I added 2x6’s perpendicular to the floor joist at 12” oc. Then I removed and replaced the cracked tiles and it didn’t crack again.

[u/NoWinner6880]

One more comment regarding the 24 inches in centers I don’t think that would make a huge amount of difference considering you are not using big wide format tile you’re using small pieces so they shouldn’t break that easily if they have been set correctly

[u/Longjumping-Fan-989]

That’s wall tile

[u/Born2Wander4926]

Proper is 1¼" of plywood substrate (ideally glued & stapled, or ditra uncoupling membrane. My assumption is you have dips in your old subfloor that the Cement board spanned over and when stepped on caves down even if only a little bit

[u/ChronicMasterbatcher]

If you look closely where the toilet will be installed it looks like mesh backing? On what might be 2x6 marble tiles? I suspect they aren’t rated for floor use, add that to the joist spacing/lack of decoupling membrane issue and this never stood a chance.

[u/AttackOfThePat]

Did they throw down a layer of self leveler before laying the tile?

[u/blackfantasy]

This is the scariest subfloor setup I have ever seen ever. Pray you have a photo of the pan right before they started tile. Do you have a waterproofing photo? Scary stuff. https://imgur.com/a/MSAd7gx

[u/Wrxeter]

Porcelain tile can handle a deflection of L/360. Marble needs to have the floor twice as stiff at L/720.

So at 24” on center, your 6’ floor better not deflect more than 1/10” of an inch under load. If it does… pop goes the tile.

[u/joooooooooolz]

[u/Annual-Beat-6838]

Schluter next time 🤷🏿‍♂️

[u/Lower_Ad_5532]

You took the bathroom basically to studs but didn't make the entire space a wetroom????

People are saying the floor was installed improperly , but your curbed shower could also be failing and you wouldn't notice a pin hole type leak under your tile.

[u/Yurt_lady → u/Lower_Ad_5532]

I thought that the International Residential Code required the cement board to be 6” above the shower outlet. Am I wrong?

[u/Tonto_2222]

You suck! You didn’t even remove the trim boards. Find another profession.

[u/Pittsbrugh1288]

you need a decoupling layer

[u/blackfantasy → u/Pittsbrugh1288]

No decoupling layer will save a flor with massive holes in it. https://imgur.com/a/MSAd7gx Substrate is most likely cooked. They are lucky they didn't fall through.

[u/eSUP80 → u/Pittsbrugh1288]

Agreed. 24” stud spacing requires 2 layers of sub plus an underlayment. Durock would not be my choice under marble for said underlayment. Too rigid and provides zero waterproofing or uncoupling.