Kerdi, sheetrock & the Plumbing codes?

[LazyPup]

I am a master plumber by trade so I hope you will understand that I am as dumb as a box of rocks when it comes to Kerdi systems, however I have a serious question regarding the use of membranes and sheetrock for shower walls.

Both the International Residential Code (IRC) and the Uniform Plumbing Code (UPC) prohibit the use of Sheetrock or Water Resistant Gypboard (Greenboard) under tile in a shower enclosure until the wall is at least 70"(IRC) & 72" (UPC) above the elevation of the finished drain.

The codes do permit the use of water resistant gypboard (Greenboard) on all walls except within the shower encloser.

Water resistant gypboard (Greenboard) may not be installed on a ceiling if the framing is greater than 12" on center.

REF: IRC 702.4.3 & 702.4.2 UPC 2512

Personally I like the membrane system and see where it could have some distinct advantages in my business, however I don't care to get in the proverbial cussing contests with the local inspectors

I like to feel that I stay current with all the major plumbing codes so perhaps you can advise me if the Kerdi system has received a recent code approval that I am not aware of.

[sometimer]

Lazy pup, checkout this thread: upc links

[John Bridge]

IRC has outlawed the use of greenboard directly below the tile. That's all. They have outlawed "sheetrock showers" after all these years. It has nothing to do with the Kerdi method.

[LazyPup]

The links show the Kerdi system is approved for the shower pan and drains, however that does not address the quesition of the walls.

Under the International Residential code the only materials currently listed as approved for walls behind tile in a shower enclosure is cement backerboard.. IRC 702.4.1

The Uniform Plumbing code says it is up to the local authority.

[sometimer]

that seems odd....with a waterproof membrane it shouldn't matter what's behind it.... it's a dry area.