Green board in shower surrounding [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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01-30-2017, 03:06 AM
I just had the shower in my kids bathroom re-tiled and I'm afraid the gut we used did it wrong. The house is 12 years old and the tile that was there before was just sheets that had been glued to the wall.

The guy that did the new tile left the green board that was there, scraped off and residual glue, used aqua defense and then tiled over it. He also added a niche on top of the green board.

I'm looking at doing my tub surround in my master myself so I've done some research on what I need to do. From everything I've read it sounds like what the guy did was mostly, if not completely, wrong. My question is, how bad is it? Do I need to have it re-done before it can be used? Any advice would be great.


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Todd Groettum
01-30-2017, 06:46 AM
You paid for it, you might as well get some use out of it....when Mold starts to show up its time to re do it...should take awhile...My biggest concern short term would be that niche....

It will hold up best if you wipe things down after use...

Houston Remodeler
01-30-2017, 07:33 AM
Start saving for a new shower. We can't say exactly when this one will bite the dust, so you'll have to keep an eye on it.

HooKooDoo Ku
01-30-2017, 08:19 AM
I didn't think Aqua Defense was approved for use over Gypsum wall board, so I looked it up and was surprised to see their instructions include the following:
Gypsum wallboard (walls/ceilings only, in approved application areas

Houston Remodeler
01-30-2017, 08:53 AM
AD isn't approved over MR board in showers and MR board isn't approved by the manufacturer in wet areas for the last few years.

01-30-2017, 09:00 AM
Welcome, J. :)

Most of the manufacturers of direct bonded waterproofing membranes will tell you, in a candid moment, that their products will work quite well over a gypsum backing board in a shower, they just can't publish that due to the current code restriction on the use of such gypsum products in wet areas.

Shower might last a long time if the work was done well, but it's still not an acceptable installation according to building code and tile industry standards. The junction of the gypsum board and the tub is the most likely point of early failure and the place where your installer probably didn't do what would be necessary if he wasn't even aware that the MR Board wasn't correct for the application.

My opinion; worth price charged.

01-30-2017, 09:54 AM
Thanks for all the comments and advice! Now that we're moving on to the master bathroom, I'm going to be replacing the green board. What would be an ideal product to use? Would the green board be in all the walls/ceiling in the bathrooms? Should I be replacing those? The only mold issues I see are in the master shower. We've been updating the house little by little and we've done all of it ourselves except for the tile. This is one area I'm not comfortable in and want to avoid a major mold issue. Thanks again.

01-30-2017, 10:17 AM
1. Just tear out the green board in the tub/shower area, the rest can stay including the ceiling.
2. Really depends on budget, there are a lot of choices.
Wedi and schluter kerdi panels (easiest but higher cost)
Schluter, Wedi, USG, Hydroban, Ardex, Noble are some of the fabric membranes available for use
Lots of liquid waterproofing options
Go board
Or any of the cbu options installed properly in conjunction with a moisture barrier, fabric membrane, or liquid waterproofing

01-30-2017, 04:18 PM
Thanks rmckee! I've been reading some other threads and I think with the info I have hear, I've got a good idea of what to do.

I really appreciate all the help.