And, John, you still can't get it through your head that when behind a totally waterproof membrane applied system (and
system is key here - they call it the Schluter Kerdi shower system for a reason, impling a
TOTAL design, not patchwork), the drywall is NOT in the shower, just like it isn't in a wet area next to the windows, or on the ceiling under the roof.
Nobody is saying using drywall IN a shower is a good idea when just tiled or with a system that has not been tested and approved, but with a properly installed, tested, and approved material like Kerdi, it is perfectly fine. If the manufactuer has independent test results proving it is a viable method, the TCNA defines the procedure as an acceptable method, and the governing agencies approve it, practical experience for decades has proven it...local exceptions aside, it is a viable method to build a shower. That you prefer other materials or methods is not a problem with me...your direct disregard for the nationally approved testing agencies against a proven method is approaching slander.
For example, here's the Massachusetts state plumbing approval listing for Schluter Kerdi
http://license.reg.state.ma.us/pubL...er&model=&product=&description=kerdi&psize=50
For you to say it is not approved, is just ignorant and wrong. There are similar approvals for most places, if you care to dig them up, local exceptions aside. The Schluter Kerdi Shower system works as advertised, and as advertised, lists drywall as an acceptable membrane backer material. For you to say otherwise, is just plain wrong.