Who cares if there is drywall in the shower?
Who cares if dry wall is behind the waterproofing in a shower? In a steam Room. In a commercial kitchen. A livestock plant. Outdoor BBQ. Any where that would be considered a wetzone Dry Wall is not permitted.
Originally Posted by mtcummins
I care because so many shower's fail. Many kids and old timers working in large box stores are under the impression Green Dry Wall is waterproof and Mastic is the proper setting material. Scary how wrong that is.
TTMAC cares because they study failure after failure and develop National Tiling Standards that promote proper builds.
The NTCA care and does recommend dry wall either.
The ANSI Specification guide also cares and like the TTMAC also develop new standards.
It might surprise you that some of Schluter's top men are on these chairs. For example Dale Kempster is Schluter's top tech. Why not shoot him an email and see if Kerdi is OK over dry wall in your shower. Dale Kempster <email@example.com>
Drywall has a paper backing and this backing is perfect for mold growth since it get's a food source. Condensation behind walls can cause drywall to fail and then stress the wall assembly more. Cold water lines not wrapped on warm days can drip. Also drywall is not that strong. Setting tile often involves beating the tile with a rubber mallet or pulling a tile off to check mortar coverage rates.
I would bet the men and women that make up these industry standards could add point after point to my list.
So why in the world would anyone use drywall in their shower? They might if they read that it is OK on the Kerdi instructions. And it is, around your kitchen backsplash and stove. Maybe along your laundryroom backsplash as well.
If you read this Document from Gypsum Nexus (The Gypsum Association) you will get a better understanding all the new code changes envolving drywall use in bathrooms. At the bottom of the first page on the right it makes mention that Green Board (water resistant) drywall is permitted in a bathroom renovation but not in the "Wet Zone".