where tiled wall meets tiled shower floor

[ambaji]

hello and help!
We've got the Kerdi membrane installed over the newly built shower stall. The quarter inch thick tumbled porcelain 4"x4" + 6"x6" tiles have been installed with Mapei Kerabond/Keralastic. We're ready to grout (we have the Mapei ultracolor grout).
It seems that the seam where the tiled walls meet the tiled 30" x 40" floor is to be caulked rather than grouted. iIve also read that it should be first grouted, then topped with caulk! What's the real scoop?
The seam varies slightly in size, but with the thick tiles resting on the Kerabond base,there are definitely places where I can insert my pinkie in, at least a half-inch, right to the Kerdi membrane -- this is not a hairline joint! So, do I pack in caulking along the four wall/floor edges, filling that void completely with caulk? If so, how long to dry? Any preferred type of caulk, or ones to avoid? I have the Mapei latex, but have read that silicone is what should be used....Also, do I first grout the stall walls and floor, then caulk the floor/wall joints, so the caulking has a dry surface to grip, or does the order not matter?
Thanks!! Your website convinced me to go with the Schluter system. Now I just want to make sure it's done right!
Jan

[Davy]

You might get different opinions on this one. I grout that bottom joint, most will caulk it. I don't use Mapei very often, don't know if they have matching caulk or not, someone else will come along and help, sit tight.

[opiethetileman]

mapei has matching chaulk to some colors not as good of a selection as custom or ccure

[Davy]

Thaks Op.

[ambaji]

The Mapei caulking has about 30 different colors, to match their grout. Their ultra-premium grout Ultracolor is not portland cement based, and therefore has no problem with efflourescence -- great when getting into colored grout. The color is also not supposed to change. It carries a lifetime warranty, vs. 10-year warrantee for their next-best grout. I'll let you know in 10 years!

[Mike2]

When you grout it Jan, make sure to use a sanded version.

[Shaughnn]

I recommend grout. I've had too many troubles with color-matched caulk re-emulsifying and crudding up. If you built it right, there won't be any movement at all to worry about cracking the grout and it will allow your walls to weep.
Shaughnn

[Jim Farrell Tiler]

Use the Mapai silicone do it once do it right, silicone is far better than caulk which shouldnt be used in wet areas ( not on our side of the planet anyway)

jim

[John Bridge]

Hi Jan,

I vote for grout. Sorry, Jim.

[ambaji]

Thanks everyone for your input. I called the Schluter rep and asked his opinion.
He felt that it was six of one, half a dozen of another. The grout could crack, the thick wad of caulking could look really really ugly. The Kerdi membrane would keep it all waterproof, however. Cracked grout does have cleaning issues, as does lots of caulking.
We ended up grouting (yes, sanded grout) and I'll keep an eye out for cracks.
Thanks for all of your feedback. Researching all of this is really a fun learning experience! Onto the kitchen reno....
Jan