Carrera Marble - Cracking

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Old 07-03-15, 06:01 PM
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Carrera Marble - Cracking

I think I know the answer to this: "You won't know until you rip up the tile" but I'll throw out a Hail Mary.


Location: 2nd Floor BA
Tile: 18X18 Carrera Polish Marble
Subfloor: Existing 3/4" plywood, new 1/2" ply, and 3/8" hardibacker
Installation Date: 2/1/2015


Issue: 3 cracks in the tile (#1 - Extends 2 1/2 tiles to the the shower wall in which my finger nail extends into the surface crack; #2 Extends 2 tiles about 2'-3' away but has not penetrated the surface (yet); #3 extends 2 tiles about ~2' away and slightly penetrated the surface) The only commonality between the cracks is that they appear to run in the same manner of the floor joists. However, I don't think any root cause can be determined under the tile is ripped up but unsure what information that will give me given the multiple layers of subfloor.


Proposed Solution: Per the advice of 2 different tile folks: Rip up the layers of tiles and screw down the hardibacker in multiple spots, use white superflex mortar, and reinstall the tile.


Does anyone have a better solution?
 
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Old 07-03-15, 07:09 PM
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Bummer....Sorry you're having this problem.

Give us the; size of the floor joists, their spacing, the unsupported span and try to figure out the species and grade. How old is the house?

Do you know how the Hardie was installed? Is there thinset under the Hardie, are all seams taped, how fastened? What type/grade of " ply, how fastened and is it gapped between sheets and at perimeter?

What specific type of adhesive used for the Carrara? Size of the trowel notches was there any back-buttering going on? Anything else, including any pics you took before, during and after, (especially during).

Jaz
 
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Old 07-03-15, 07:45 PM
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Give us the; size of the floor joists, their spacing, the unsupported span and try to figure out the species and grade. How old is the house?


Unknown. I was working during installation. 1999. Northern NJ if that helps.

Do you know how the Hardie was installed? Is there thinset under the Hardie, are all seams taped, how fastened? What type/grade of " ply, how fastened and is it gapped between sheets and at perimeter?
Unknown. I believe the hardie was installed "opposite" of the new plywood underneath using screws.


What specific type of adhesive used for the Carrara? Size of the trowel notches was there any back-buttering going on? Anything else, including any pics you took before, during and after, (especially during)


Unknown but I have pics. E-mail for me to forward?
 
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Old 07-03-15, 08:03 PM
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Sure, go ahead and email the pics. You also should be able to post them here for all to see.

We're not getting anywhere if you don't answer the other questions. The first grout of Q's should be easy to answer.

I believe the hardie was installed "opposite" of the new plywood underneath using screws.
So I guess you think there's no thinset under the Hardie. That's not good.

Jaz
 
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Old 07-03-15, 08:41 PM
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Sure, go ahead and email the pics. You also should be able to post them here for all to see.

We're not getting anywhere if you don't answer the other questions. The first grout of Q's should be easy to answer.


Understood but I was working during the project so I don't have much to offer except the current problem. I do have the architectural PDF of the house but unsure if that provides the information you need. I wouldn't be able to provide the answer of the 1st set of questions as I don't have pictures of the floor joists.

I believe the hardie was installed "opposite" of the new plywood underneath using screws.

So I guess you think there's no thinset under the Hardie. That's not good.
Correct. I believe the only time thinset was used was on the top most layer.
 
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Old 07-03-15, 08:53 PM
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Here's the last of the relevant pictures. unfortunately, no pictures of the floor joists.
 
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Old 07-05-15, 07:47 PM
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Aren't the floor joists exposed anywhere? Let me know cuz you don't have to see them to measure them and I can tell you how.

If the Hardie was not installed with thinset under it, that's a major error that could definitely cause tiles to crack. I also suspected that the joists may be over spanned for marble and possibly the " underlayment may not be gapped as it should be. Just a guess on the last two items.

I'm not sure what to make of some of the other pics. I can assume a few things though. Looks like the shower floor went from subfloor to membrane directly on the subfloor with out a pre-slope under the membrane. That is wrong, but it's common to do it wrong cuz no one checks.

On the shower bench, since the pics are random and there's a few steps missing, I can only assume that the contractor simply fastened the Hardie (?) right over the membrane. If so, that is wrong and chances are he did the same for the curb and other low areas.

Can I assume there's no vapor barrier behind the Hardie or any surface waterproofing on it? Are you having any issues with the shower yet?

Jaz
 
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