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Discussion Starter · #1 ·
The project architect specified large format, thin porcelain tiles (4'x8') for a shower with a floating bench. My tiler (who is excellent) has only installed these tiles when they were pre-cut. Unfortunately, that is not an option in this case. We had no problem cutting the tiles for straight lines and drilling holes for the shower faucets and trim. However, when we tried to make the cut out for the floating bench with the grinder, the whole sheet cracked. Any suggestions on what we can do to avoid cracking? The tiler suggests attaching 1/4" wondeboard to the back of the large tiles and then cutting. (He has done this for backsplashes). I can't seem to find anyone else who has done this? Should we score the cut-out with glass cutters before using the grinder or place thin carpeting under the tiles when cutting to reduce vibrations?

We only have one extra tile (and they are back-ordered from Spain for 2 mos!), so we need to get this right.

Thanks!
 

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Not my thing, but I would think drilling a hole for the corner intersection, then snapping to it, both ways. Drill the hole on absolutely flat ground (ply) with it fully supported. Just a thought.... good luck. (Or drill with it fully backed against a flat wall, maybe??)
 

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Discussion Starter · #5 ·
Yeah, we drilled holes in the corner, but when we cut with the grinder the panel cracked. So, my tiler wants to attach 1/4" wonderboard backer to prevent cracking and then attach the entire unit to the shower walls. Does that sound reasonable?
 

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or install the panel in place, then go back after it's set to cut out the notch by hand. You would have to be creative with the water proofing, but I could map it out.

Dimensions matter, but you didn't provide any for us to go off of.
 

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The tiler suggests attaching 1/4" wonderboard to the back of the large tiles and then cutting. (He has done this for backsplashes). I can't seem to find anyone else who has done this? Should we score the cut-out with glass cutters before using the grinder or place thin carpeting under the tiles when cutting to reduce vibrations?
We only have one extra tile (and they are back-ordered from Spain for 2 mos!), so we need to get this right.
If the tile guy knows how to do it that way (first attaching 1/4" wonderboard) then that might be the way to go. 72chevy4x4 's suggestion of installing the sheet first and then cutting the opening is what I have heard is the way it is done.
Don't score the cut-out first. That could increase the chance of cracking.
The idea of first drilling a hole in each corner is what I would do.
Did the tile guy use water to cool the blade and tile as he cut it? The heat generated will increase the chance of a crack in a long dry-cut.
I would use a portable 4" wet saw with a turbo blade and a good fence/guide. I would not make a full cut on each first pass and I would set it to barely make it through on the second pass. you will probably need to go deeper afterwards on the part of the cut near to the hole to finish. Easy does it to keep the vibration down. If the saw base is on the tile, I would make sure there was duct tape on the saw base to reduce vibration and scratching.
 

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You guys realize that large format tile such as these usually requires a tile setter who has been certified to install them? It's not like traditional tile. The tile is under some pressure that isn't being considered. Just being a tile installer doesn't mean you know what you are doing, the evidence is in the fact that the first one cracked. I will post on some Facebook Tile Groups and get back.
 

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Hair Splitter
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Hair Splitter
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Here was an addition by someone who specializes in thin LFT.

Spain- Cosentino Dekton 8mm? If so make sure you are using the right core bit at the right RPMs (6,500 with variable speed grinder) ultra compact different animal than porcelain - finicky - with mark score long and grind short w/ Monty CPV 4.25"
 
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