What caused this marble floor tile failure?

QUESTION

What caused this marble floor tile failure? Attached are the photos I have from the removal of a 2x2 marble tile in the living room of the home. It appears to be wooden decking subflooring on dry-pack with thin set below the ¾” thick marble tile, but I hope you can help clarify if that is correct.

Also, the below beam had signs of movement from cracking of the drywall covering the structural support beam beneath the tile shown in the attached photos. Please let me know your thoughts.

I am involved with this failure on behalf of the insurance company. There was a large storm that came through and caused some damage to the roof and some exterior elements. The homeowner is alleging that water damage caused damage to the marble tile substrate which created movement of the tiles. However, no evidence of water damage inside exists from what I can see. Is this damage indicative of water damage? Could moisture have caused the de-bonding of the thin set? There was some movement of the structure evidenced by cracking of the drywall covering a structural support beam. The beam was OK, but the drywall cracking indicated there was some movement which could have loosened a tile and created the domino affect allowing other tiles to move as well.

It appears to me that movement of the structure caused the tiles to loosen and/or move. Then, the grout cracked and slowly deteriorated allowing other tiles to move. I agree that there are more than one contributing factor here, and the bonding of the thin set is likely one of them. Also, as you mention compaction of the dry pack was questionable as well. This area of the flooring is near large windows and in a high traffic area which may also be contributing factors to the movement of the marble tiles once they de-bonded (or the grout was compromised) from the thin set.

The tile was removed using a suction cup (one small one). It was simple to remove, other than the weight of the tile and weak suction ability of the suction cup that was used to remove it. The thin set appeared to NOT bond to the fiber glass backed tile at all. Your comments are appreciated...

ANSWER

ANSWER - Keep in mind that when there is problem it is generally  not due to a single deficiency, but due to multiple compounding deficiencies.

Looking at photos I note the following, but I can’t state what the significance of it is until  I know what is the alleged problem and what are the symptoms of the problem, so I can put the photos into context.

Looks like the thin-set adhesive received at least 95% contact between the stone and the substrate.  Although there should be full contact along all edges and corners, the lack of that in the photos doesn’t seem significant.

Looks like the thin-set adhesively failed to the back of the stone, but that isn’t meaning full unless we know what amount of force was required to cause that failure when you removed the stone.  Looks like the stone came up in one piece, which generally suggests it wasn’t bonded well.

I see that the thin-set pieces removed cohesively failed in dry pack mortar bed.   Mortar bed looks loose which might be due to lack of compaction or lack of finishing the surface, or due to how that area of thin-set was removed.

I see a texture on the thin-set surface where it debonded from the marble tile.  What does the back of the removed marble look like?  Does it have a fiberglass resin back?  If so, then they should have used an epoxy to bond it.

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