Grout or expansion joint in shower

I have a "one piece floor unit" on the bottom of the shower. The bottom row of tiles right about the floor piece - should there be grout or calk in this joint?
Also for the corner joints 1) Should the tiles be mitered cut and 2) Do the corners get grouted or calked or both? Thanks.
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I'm not a professional tiler but...
Whenever there is a change of plane (corners or floor) the joint should be caulked.
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Also not a Pro.
Between the pan and bottom row caulk.
In corners, I would also caulk. Some claim that if it is a mud wall ( tile set in a mud (mortar) base that is 2-4" thick then you could consider grout. If you are using cement backer board or Sheetrock (a real mistake) then definitely caulk.
For inside corners, I would mot miter the tiles. Just maintain a consistent gap. For outside corners, I would use the special end cap pieces or miter if necessary.
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snipped-for-privacy@hotmail.com wrote:

Thanks. That's what I read in the "bible of tiling" by Micahael Byrne. It just seems really odd because an entire seem (a corner) that gets pegged with water while in the shower, sealed with caulk just seems "flimsy" to me for some reason. (I do understand the concept of the expansion joint though.) It's just the water aspect of it that seems odd. The other thing is that when I look at other bathrooms I never see calk at these two joints - even by self proclaimed pros.
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On 19 Apr 2006 18:36:42 -0700, poison snipped-for-privacy@yahoo.com wrote:

If you use silicone or polyurethane caulk, it's more waterproof than grout. Especially grout that's cracked because the joint is moving from expansion and contraction.
If you've read Byrne, then you know you should have a waterproof membrane behind the backerboard anyway, and it should wrap the corners so there is no seam there.
Seems like overkill, I know, but if you want it to last a long time without leaks, it's a tried and proven method.
Good luck with your shower,
Paul
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