Flooring Tile - Tile Shower leak

I have a tiled shower with a fiberglass pan. The shower start by the door hinge area. I remove the door completely (will be replace at a later date). I had to remove some 4x4 and bull nose tiles to a point where there is no water damage. The tile was installed in green board only. I removed the wet green board and replaced it with new green board. Cleaned the old adhesive and grout from the tiles. I purchased a premix adhesive\grout and replace the tiles. While I was at it, I re-grouted the entire shower as it needed it. All looked great. After 3 days of letting the grout set, I sealed the grout. I waited another 2 days before I used the shower. For now, just a curtain was installed. 8 days after I re-grouted, this morning I was using the shower and I noticed the grout was mushy. I could just wipe it off. Baffled. What would make the grout do this? Could it be we use a shower spray (like Tilex) to keep it clean from hard water spots? I have never seen this problem before. Usually, when grout dries, it is dry.

Any suggestions of what to do now would be appreciated. Thanks.
mchristo63

Are you sure you used grout?....

wait a minute.. premix grout / adhesive? I don't think it's
made for a constantly wet area. re-read the instructions.

Unfortunatly, there is more bad news.

1. Don't use greenboard for shower surround, use cement board with a vapor barrier

2. Don't use premix thinset. It's really mastic and it's no good for tub/shower applications. When it gets wet, it softens up. (as it sounds like it's doing for you.) Use the thinset in a bag that you have to add water to.

3. Grout should come in a separate container. I use premix grout, but others would probably advise against.


Sorry dude. Sounds like you're gonna have more work ahead of you.
At the very least you should scrape out the adhesive/grout and regrout the shower with a real grout material.
Then you can seal. It will probably hold for a couple of years. just make sure to check for loose tiles now and again.

You mentioned a vapor barrier, is that like roofing paper behind the cement board?

I agree with don't use the green board in wet areas, but it seems like a lot of new homes in this area are using green board for showers and then tiling directly.

I will most likely replace the grout that is there and redo with a specific grout material. If I have problems in the future, I will completely remove the show stall and redo with cemet board.

thanks
mchristo63

Tar paper or even a plastic sheet would do.

I just talked to a couple "tile guys" and they advised to NOT use the pre-mixed grout for a shower.
You will have the same trouble.

Kitchen back splashes, and non-shower walls in a bathroom are okay, but not in the shower itself.

Good luck.

And if you ever re-do the bathroom, don't put that greenboard back in. :)

Thanks.

I finished removing the grout from one of the shower walls last night. Other than using a grout remover tool, is there a better way to remove grout. Hard work.

Not really. Since it was a premixed grout, a carbide scoring knife might go through it pretty good. For other areas with thin nonsanded grout lines, a hand held grout saw is the way to go. There are bits for rotary tools, but if you drag across a tile you will do some good damage. JPicasso, I think you were thinking mastic for backspashes and dry bathroom walls. Also, don't use mastic on a tile larger than 8x8 and just stay away from premixed grout all together. It shrinks excessively and is prone to pinholes and cracks form the water from the clean up process.

Thanks all. Great advice. I think all will be good now.

Break time, :coffee:

I am about to re tile my shower stall. The old tile has been broken out and there is the old substrate left behind on the walls. It seems to be cement plaster on metal lath. Except for vertical cracks in a ll four corners, its in good shape. Now should I scrape, clean and tile over this or should I put up cement board and then tile? Where does the vapor barrier go, over top of the cement board or behind it? Also what kind of tile bed should i be using... adhesive, pre-mix thinset mastic :confused: :confused: ...? and what kind of grout? Please help. :)

Vapor barrier goes behind the backer board.

For the plaster wall I've heard "they make a great base for installing tile over since it's already concrete based" Guess your supposed to sand it well with some course grit sandpaper to give the thinset something to adhere to when setting the tile.

I've personally never tried it, always liked to just go and knock out the area I'm working in to the studs and build up from there for peice of mind. Hopefully somebody can give an experienced answer on that.

There is no better base for ceramic than an old mud job properly done. However, most often, there was no moisture retarder placed over top of the studs. Since I am the one that will be called back if there are water issues, I will always replace the walls with a moisture retarder and cement board. Those cracks in the corners will be a weak spot in the installation. If you just caulk them and it fails, water will be getting back there for probably quite along time before you notice. I've pulled out many old walls like that and some looked like new framing and some needed most of the framing replaced. You want to use modified thinset to set your tile. No mastics or premixed thinsets. Use only the modifed thinset in a bag. Same for grout. Use only grout from a bag. Non sanded for less than 1/8", sanded for grout lines greater than 1/8" and 1/8" is your choice, but some wall tiles with softer glazing can be scratched with sanded grout. Calulk the wall corners and the bottom of the tile-no grout.

Thanks guys,
Looks like I will be taking off the cement plaster and putting up cement board. Rather be safe than sorry. Do I have to tie-in the vapor barrier to the floor pan (pre-existing cement concrete base with hexagonal tiles over top) and then re-tile the shower base ?... I am thinking that otherwise the subsequent wall leaks will drain onto the subfloor :eek: I have lot of demo to do :wall: