Builders–what do you do differently from the traditional tile shower with a steam shower? My understanding is a traditional shower goes like this: Pre-slope deck mud, membrane up to 12″ of walls, more deck mud, then tile, CBUs on walls, then tile. But doesn’t the TCA calls for all surfaces in a steam shower to be covered with a vapor barrier?
I have no vapor barrier between the CBUs and the studs. Two of the three walls are outside walls constructed of SIPs, with the CBU directly fastened to the OSB. In tearing out a closet wall opposite the shower, I see water wicking up to the membrane edge, then wicking up further where the studs contact the CBUs. A stick built house might be able to work off the moisture, but for an OSB-foam-OSB sammich, water is getting into the OSB.
I have some drywall failure next to the shower that indicates vapor is getting under the drywall. This would mean the steam is getting under the tiles and CBU, hitting the foam and coming back out through the drywall. See pics.
Builders, what would you do? What is your practice?