As a contractor that rule must be a pain as you must lose business. These showers are usually built on site and IMO if you are asking this you sould be looking into how to do this or get a pro who has experience
Please...and you are asking for help on this site. The only contractors that I know who do not answer calls from a phone number they do not recognize are the ones who are being hunted for doing a bad job....Good Luck!
We put no-curb showers in almost all our projects, and find that on-site installation of a tiled shower and floor with a linear trench drain is our--and our clients'--favorite method:
Patricia Colwell Consulting
shirlpp
Advantage Services Construction