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.
Winn Erdman Steamaholic 291
Last edited by placitassteam; 06-24-2020 at 04:35 PM.