Shower Tile Grout

[seanflorida]

The grout in floor of the shower chip out a couple months ago leaving a void to the concrete below (first floor, poured slab, no basement - Florida). The grouting throughout the house is pretty poor - a lot of hollow spots breaking showing a void to the bottom floor. Anyway, I knew I would have to let the shower dry out before I re-grout. And I knew I wanted to fix more problem areas that looked bad (cracks in grout - not on the edge). So I got the Dewalt and went to town - found a lot of weak grout that just came out like no business. During the course of doing this, not surprising some of the tile came out. Naturally in the area that had the missing grout I let go for a couple months was moist underneath. But in another area that didn't really have missing grout (couple feet away) was moist underneath as well - it even had a pinkish mildew type color as well where the grout met the concrete. Now I know grout is porous and water can seep below, but is this all normal, or was the grout just utter crap? Should the underside of the tile be moist and that's just what showers are like?
What is the best route re-attaching the tile - chip out the thinset and redo? I'd prefer not to 86 the whole floor (5x5 roughly).

Attached are pictures - the picture of a lot of missing tiles is where a small section (half inch long) of the grout was missing...and another picture where the grout look weak/cracking and had mildewy pink crap.
Appreciate the advice.

 

[seanflorida]

Florida code at the time (2013) had an exemption for liners if the shower was built into the foundation. As such, I don't think they went with a drain with weep holes.
I'm leaning towards gutting the floor and installing new tile.
Thoughts?

 

[Sponsor]

 

[Jadnashua]

The national plumbing codes (there are some local adjustments) REQUIRES any drainage surface to be sloped to the drain. The tile is NOT the waterproofing, it is a decorative, wear surface. To put in a proper, sloped membrane would require tearing up not only the floor, but up the walls nearly a foot (there can be no holes in the liner beneath 2" above the top of the curb). By the time you've done that, often, it may work out better to just tear it out and start over. Trying to match tile on the wall, and maybe a complementary one on the pan often compound the problem. Without a sloped liner (not one flat on the floor, which is the next biggest common mistake) would allow the moisture to drain to the weep holes (assuming good workmanship!). The pan would still be wet, but constantly be flushed. Mold requires three things: water, spores, food. The mortar and tile aren't food, but soap, skin flakes, etc., are, and you will have water there and spores. Especially in FL, that area being moist often starts to rot out the studs, and also draws carpenter ants and termites...much better to make the whole thing waterproof!

Personally, I prefer to make the whole shower waterproof verses not being damaged by water. This requires a surface applied membrane of some sort. www.schluter.com makes one and you can view some extensive videos on how it works and how to install it on their website. There are other manufacturers that make similar things. A conventional shower does work, but only when it is installed properly. I think a surface applied membrane shower works better. Check out www.johnbridge.com for help with tiling.