I posted a week ago feeling very daunted by the instructions for fitting a stone shower tray and questioning the need for bedding it into mortar. Thanks to all for the very helpful replies.
I have now built my frame and cut the 18 mm ply to shape. What concerns me now is how thick does the mortar needs to be? My problem is that there is very little space between the top of the compression fitting on the shower waste, and the bottom of the ply. I guess I can chisel out some of the ply to give greater clearance, but it would be helpful for me to have an idea of how thick the mortar should be. I guess not very thick as I did find flexible floor tile adhesive recommended as an alternative. Any thoughts?
Keith