Hi, I'm hoping someone can save my failing eyesight from staring at this tiny phone screen for 12 hours and help me answer this question. I've already talked to the very nice people at Mapei customer service, but unfortunately their tech support center is still lights out in Florida after hurricane Irma. Don't they understand I have tile to install??!
We're installing a 5x7 steam shower in our rehabbed 1870's farmhouse (swoon, right?) and our guy likes AquaDefense for the job. Over Redgard. Over Kerdi or Noble (which he's never worked with.) At first we thought he was showing his incompetence since Mapei's installation guide specifies using an additional vapor layer in steam shower applications, which he denied. Then while trying to convince him he HAD to switch gears and go with Kerdi/Noble/Redgard for vapor control, I find THIS on Mapei's (new?) 2016 install guide:
"ASTM: E-96 Method E, meeting requirements of <0.5 perms"
What gives?? Everything, and I mean EVERYTHING, I've read online about AquaDefense says it requires an additional vapor barrier in steam showers. But if this information is correct, it's even less permeable than Kerdi. Than everything except for Noble! Did they change their formula to match Redgard? Is it a typo?? I'm about to gouge my eyes out, please Obi-Wan, you're my only hope!
Lisa in Riverside