DIY Custom Shower Pan on concrete slab?

That's a great question and I have had a similar job done in the past. Go to one of the big box hardware stores or a plumbing supply company and get a rubber or vinyl membrane made for this purpose. You lay the membrane over the floor of the shower area and carefully fold at the corners. Nail it to the wall studs above any possible water line. Now put your first layer of mud on top of the membrane and let it dry. Then you can tile over the mud. If you do this properly the shower will not be able to leak at the bottom. Be sure to use backer board on all the walls and make sure the membrane is underneath the backer board. Here's a link to articles that demonstrate this method. a href="http://web.diynet.com/diy/web/searchResults?searchString=shower+membrane" rel="nofollow"http://web.diynet.com/diy/web/searchResu…/a