Need advice on standup shower tile and grout repairs

[HUP]

For cosmetic reasons, I just finished scraping and resealing around the shower door frame. After tackling that I decided to scrape and reseal around the base of the shower. When removing the old caulk I noticed a bit of dampness under the seal and grout cracks where water penetration has gotten in. Now I'm into removing old grout! EEK!

What should I use to fill the larger gaps in all corners of our shower stall? Is there a type of air can I can use before applying the grout and caulk? It doesn't seem like the deep spaces were filled enough to stop the grout cracks from occurring. Also, which is the best silicone caulk to use? I have been using anti-bacterial microbeaded silicone that states "lasts 30 years". I want to do this right.

HELP!!! It's appreciated!

Thanks for reading!

[HayZee518]

you've got to realize that in a tiled shower NO GROUT will EVER be completely dry. moisture will ALWAYS be there. The floor especially will always seep water into the drain. when you re-apply grout, don't seal over it for it won't breathe.

[HUP]

The dampness was felt a week and a half after the shower was last used. I like the idea of using grout sealer. I would like to seal it so water doesn't penetrate the shower's surrounding drywall. I'm also looking for something to inject behind the grout joints.

I have a good habit of ventilating the bathroom. The windows are open 24 hours a day when possible. The shower door is always left open as well. What you see is the product of the previous owners.

[HayZee518]

I'm wondering what the wall is made of - green board? cement board? regular sheetrock won't stand up to water.

[HUP]

I'm unsure! It's hard to see in the grout spaces where I chiseled out the existing grout at the base of the shower. I see a gap about 2-3 inches deep and some kind of mesh looking texture on board behind it. The mesh texture reminds me of what you would see on drywall mesh tape, though I can't see it too well. I hope it isn't regular drywall. The color is like regular drywall back there.

I hope it is waterproof board! I would also like to hope the cause of our leaks are more like broken seals. When I mentioned drywall, please keep in mind that I am no expert. I mean the drywall on the front of the shower stall has signs of a small leak seeping through.

I think the problem is a bigger issue. I now notice small hairline cracks that have formed along other grout lines. This leads me to wonder if there is drywall rotting behind the lower part of our shower.

This house was built by GOONS! LOL

[HayZee518]

I looked closer at your picture and it doesn't seem like there's much behind the tile back there. greenboard's been around for at least 30 years but beyond that ???
there is a void behind that one corner. Now, since you don't want to remove the tile, we got to fill in that corner with something. I would say maximum expanding urethane foam insulation. the urethane foam expads due to humidity [moisture] fill in what you can and let it cure, then trim it down with a knife to the thickness of the tile. Now mix up some grout and use a rubber float to apply the grout. Really press the grout into the joint until it won't hold any more and let it dry. the film that shows up on the tile surface, wipe down with a damp sponge. if there is a film still, use a balled up burlap bag [cloth] to further clean it and burnish the surface.

[HUP]

Sounds good! I second guess myself too much. Thanks for the advice! I'm all set to get the job done now!

Ultimately it would be nicer to remove the tile and replace the sheets behind. Fortunately, the house just turned 8 years old and I may be able to avoid further issues.

Thanks again! It is appreciated!