I have found myself in a situation where the contractor installing our walk in shower seems hell bent on installing it without a shower pan liner.
From what I can deduce he's approaching it this way (because he's had to break up the mortar once already).. 1) install the drain, 2) put mortar down almost up to the top of the drain. 3) Tile it 4) water proof it.
Everything I have read about mortar pan showers says you have to install a pan liner so that when (if) the water gets through the tile it will be caught by the liner and drain without causing mold and other problems.
I'm about to ask him to terminate the work but is his approach to installation common?