Frequently I get asked for advice on steam showers, and when I do, I always reference the steam shower at my gym. I've been going to the same gym for more than ten years. Recently it sold from one national chain to another, and at that time, the new owners remodeled the locker rooms, pool and they even attempted to give the steam shower an update. The 4x4 white wall tile was overlaid by new 4x16 white wall tile (and just look at all that beautiful lippage).
To the new owners, the steam shower probably just looked heavily used. The grout was moldy, there were rust streaks coming down from the light fixtures, and they probably felt that they were dealing with aesthetic issues. If that was the case, then they were very wrong.
What they were not aware of, was that the previous owners were dealing with moisture issues for at least the ten years that I've been going there. The drywall on the other side of this steam shower has been replaced multiple times, the MDF lockers on the same wall expanded and swelled to where the laminate peeled off. If a vapor barrier was installed in that steam shower, it was either not intact or just not doing its job.
A little over a year later, I head to the gym and low a behold I see the big green octopus hanging out of the steam showers walls. For more than a week, these hoses have been pulling wet air out of the walls as they attempt to dry out the steam shower. Honestly, I wasn't even aware there was machinery like this available (obviously poorly installed steam showers isn't something centralized to just my gym). Fortunately for my gym, they could pull out ceiling tiles and isolate the areas having an issue but imagine this same scenario in a high-end residential home.
Even if they get the walls to completely dry out, as soon as they turn on the steam generator, those walls will slowly be filled back up by vapor which will condense in the uninsulated walls and start rotting out the drywall all over again. The only real resolution in my eyes is to install a new vapor barrier the encases the entire shower. However, now that they have tile, over tile, over green board.... my gut says we'll get to see what happened to those steel studs in the months to come. That or maybe they just let it run and hope for the best, either way, I sure hope they kept all that money they saved on their steam shower.
Author: Mitch Tully