# Making a rock cut with stone tiles



## Dalspots (Apr 4, 2018)

Moved last year to a new house. Working on building a new layout. I’ve got the first track to elevated on HDPE roadbed. The next track will go around the outside of the first, but cross under at one point. As this crossing will span 8’, I don’t really want a tunnel situation. I would like to make a rock cut using 12” squares of backsplash stone tiles. I’m trying to determine the best mounting method for this as the cut will be 12” tall. Planning to build a wood frame to anchor to the ground, as I will fill in the inner part of the elevated track with dirt. 
My quandary is what to affix the stone tile sheets to? I’m looking at using Johns Manville waterproof backer board. Could foam board be used? How best to adhere to any backer board?
Thanks!


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## pressta (May 29, 2020)

*pressta*

i would use cement board screwed to your wood frame or make out of cement block then thinset to attach your tile.


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## placitassteam (Jan 2, 2008)

I would agree with pressta. Build the cut out of cinder blocks and attach the tile with thinset or exterior masonry glue. Alternately you could use textured block and then you wouldn't have to attach anything. I use cinder blocks dry stacked and filled with compacted dirt. Easy, no mortar to deal with.


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## Homo Habilis (Jul 29, 2011)

A word or two of caution. Not all cement boards are created equal. Some aren't rated for exterior use and those that are should only be mounted vertically on a wall. The main failure is from freeze/thaw cycles that cause delamination over time.


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## toddalin (Jan 4, 2008)

I do retaining walls using these tile/blocks and plastic bender board. I use Marine Goop as an adhesive. Then I can do curved walls.


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