My shower stall is tiled, floor, walls, and ceiling. For some time now I have noticed that the grout in two of the corners of the floor always looked darker than the rest. Last week I scraped out this grout and found it to be moist for about 3" in each horizontal section of the wall/floor area grout. Also, there is moisture under the floor tile between the tile and the pan. I have been letting these areas dry out before I repair them, and wondering the best way to do this to prevent future problems of this nature. I stuffed a long cotton cord into each of the two opening to help wick the moisture away, which seems to be working. The grout is colored to match the tile, but I can work around that if necessary. Any suggestions would be greatly appreciated.
Thanks!
Ronbo

You did not mention any moisture getting past the pan into the floor so we might assume that the pans is still good. You should chip out the entire tiled floor and redo the floor. If you are looking for a short cut that would not require this much work you can just remove all the grout lines and regrout with a new stainproof premix grout. I would not worry too much about moisture under the tiles since it sounds like the pad is still intact.

Yes, the moisture is just between the tiles and the pan. The pan is not leaking. One of my worries has been that the moisture between the tiles and pan might result in mildew. The tile job is about 8 years old, so I think I will take easier way, and remove the old grout around the floor, let it dry out as much as possible, then do a new grout job. What do you think about shooting some silicone into this area (after it drys) before I install the new grout?

Do not shoot silicone in to the grout line, the grout should be good enough. If you use silicone the new grout will fail more quickly since it will lose some of the bonding surface. I use premixed stainproof grout with great success.

Good point, thanks! I also have a jacuzzi tub in the front bathroom that had a similar problem (with the grout around the top edges of the tub). Over time the grout would crack. Last year when I replaced the grout around the tub again... I added a thin coat of silicone over the top of the grout when it dried. So far that seems to have resolved the problem. Maybe I could do the same thing in shower? Any thoughts?

My shower stall is tiled, floor, walls, and ceiling. For some time now I have noticed that the grout in two of the corners of the floor always looked darker than the rest. Last week I scraped out this grout and found it to be moist for about 3" in each horizontal section of the wall/floor area grout. Also, there is moisture under the floor tile between the tile and the pan. I have been letting these areas dry out before I repair them, and wondering the best way to do this to prevent future problems of this nature. I stuffed a long cotton cord into each of the two opening to help wick the moisture away, which seems to be working. The grout is colored to match the tile, but I can work around that if necessary. Any suggestions would be greatly appreciated.
Thanks!
Ronbo
If the edging and corners are moving then grouting won't work, clean the grout away make sure the area is clean and grease free then use a silicon sealant with a mastic gun
Obtained from the local hardware store, this will give a flexible seal and water tight

Thanks Ronbo,I think your Jacuzzi and the shower are two totally different problems. The Jacuzzi probably isn't framed well and there is flexing of the substrat so silicone would be fine for this area. However, there should be no movement in a shower pan, they are rigid and silicone is not recommended for any surface you will walk on while wet. Again I stress that I use premixed stainproff grout and never have had a call back. When grout is done well in a shower pan it will not crack for decades.