Hate to say it, but I would look on the TOH web site. They have gone
through the membrane-laying process several times on the show, so I
assume they have a slide show of it on the web site. Mudbed with the
slope, then membrane, then thinset to hold the tile. *Slab was probably
poured with a pocket for the shower, and the mudbed built up inside it.

Thanks! Sounds logical. When to the TOH site and found a video on
replacing a vinyl shower pan but couldn't find anything on doing a
tile floor shower.

http://www.thisoldhouse.com/toh/vide...639349,00.html

Do you have a link to help on the shower stall construction?