I'm in the middle of renovating my shower and my coworker, who's helping with the tiling, suggested using green board drywall in the shower area. He plans to use mastic for the wall tiles and thin-set for the floor tiles. I'm a bit confused because I keep seeing mixed opinions online about whether this approach is okay or not. I really don't want to create friction by insisting on using thin-set and Redguard when I'm leaning on his expertise. My wall tiles are quite large, measuring 18x36 inches. What do you all think?
4 Answers
I'd strongly recommend against mastic for showers. It’s not meant for wet areas, and can fail over time. Stick to thin-set along with a waterproofing membrane like Kerdi – that’s really the proper way to tile in a wet space. Your coworker should really know better!
Honestly, his plan isn't great. Mastic and green board shouldn't be used in showers. The best practice would be to go for cement board and a waterproofing solution like Redguard, paired with thin-set. It’s honestly the safest approach to prevent any water damage later on.
A lot of professionals are moving away from drywall in wet areas for a reason. Why not suggest using Kerdi board? It's a better choice for waterproofing. Some pros can be pretty stubborn about sticking to what they know, but it's worth a chat with him!
I’ve used D2 mastic in wet areas, and it can work under certain conditions. Just not on floors, that's a no-go!