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Plumberpatty · Mar 4, 2009, 08:41 AM

Here's the situation: the tile contractor installer 30 sf 3/8 x 3/8" mesh-mounted stone mosaic. Each sheet has a dome in the middle! He swears he used the same setting material as he always does! I have never come across this phenomeno before and wonder if anyone out there has any ideas as to why it happened and how it might be remedied?
Thank you!

Bljack · Mar 4, 2009, 09:23 AM

Couple of questions and then I'll try to come up with an answer for you

What's the substrate?

What was the setting material?

Is this install grouted tight to any walls or is there room for expansion?

Can you post a picture by chance?

Lastly, what color is this stone? It isn't by chance green, is it?

ballengerb1 · Mar 4, 2009, 09:27 AM

We await your answer but I can't see anything other than poor installation. If the sheets were not domed before they were laid it must be the uneven setting adhesive.

Plumberpatty · Mar 4, 2009, 09:37 AM

Thank you!
I will get the information you need. Much appreciated.
PP

ballengerb1 · Mar 4, 2009, 09:39 AM

My guess is he buttered the sheets with adhesive rather than spreading it on the floor.

Plumberpatty · Mar 4, 2009, 09:39 AM

Originally Posted by Bljack

Couple of questions and then I'll try to come up with an answer for you

What's the substrate?

What was the setting material?

is this install grouted tight to any walls or is there room for expansion?

Can you post a picture by chance?

Lastly, what color is this stone? It isn't by chance green, is it?

Thank you! I'll get the inormation you need! PP

Bljack · Mar 4, 2009, 09:58 AM

Tile set without room for expansion tents. Normally it occurs where opposing forces come together and the tile will peak at that point. With mosaics, it's very easy to have better thinset contact around the perimeter of each sheet than in the middle unless it's thoroughly beat in. That's where the shear bond strength will be the least and where the tile will rise.

Many green stones are moisture sensitive and will actually curl if set with regular thinset instead of epoxy. The difference between the moisture in the bottom creates a varying surface tension resulting in the curling. The result with mosaics would be doming as explained why in the first paragraph. Strange, but very true.