[billyg]

Installing cement board
I will be replacing tile in a tub enclosure..At the same time I'll rip out the old greenboard and will replace it with cement board all the way up to the existing ceiling (which I'll guess is greenboard). I plan to leave the ceiling as is.
I will of course apply fiberglass tape on the cement board joints including the vertical corners...But since I don't want to spread thinset on the existing finished ceiling, is it absolutely necessary to also tape the horizontal corner where the cement board will meet the existing ceiling? I plan to install tile all the way up to the ceiling so the aforementioned horizontal joint will be covered with tile.

Also how difficult on a scale of 1-10 would it be to install tile using a "hopscotch" pattern with 12" and 6" tiles?

Thanks

 

[LeviDIY]

Billy - disclaimer: I'm not a pro. But, I just did what you're referring to in my bathroom... cement board perpendicular to sheetrock on the ceiling with tile all the way up. Its my understanding you'll still want to tape that joint. I did. I used fiberglass tape.

Where I may be wrong (I'm sure the pros here will correct if I am)... I embedded the tape on the cement board (verticle) side of the joint in thinset and on the ceiling (horizontal) side of the joint in regular compound. Was a little annoying cleaning off the knives, etc, but that was my solution. And I believe its essential to tape that joint. After tile and grout, I also caulked it as well.

As for the pattern... sorry, I did simple subway brick pattern, so no advice there

 

[Bud Cline]

Install the cement board to within a consistant 1/8" of the ceiling. Caulk that juncture thoroughly. Install the tile again ti within 1/8" of the old ceiling tile and caulk that joint also.

The hopscotch pattern is easy enough but you need to be sure the smaller tile is not exactly half the size of the bigger tile. It should be slightly smaller than half. You need to allow for the groutline. Before you buy any tile go to a showroom and layout some samples to verify the tile you choose will in fact layout hopscotch style.