In the past, I have always used Hardiboard under tile. It was suggested I use ditra this go 'round because it is a better product and is thinner, making the transition between the wood floor more level.
I watched 200 videos on YouTube and read scores of details on tile guy forums. It actually does make a lot of sense, the physics, so I went ahead and tackled the project.
After gluing the ditra to the ground with thinset (and letting it dry),
I prefilled all of the waffling with a different kind of thinset. It is rather labor intensive and I had just de-kinked my body from the hand and knees position required to do the job, when my toddler came running in to "help."
Don't worry, I fixed it.
The next day, I began on the second half of the floor tile.
(I'd done the mudroom and laundry room already, but the plumber had neglected to put in a drain for my bathtub so I had to wait for him.)
300 square feet of this charcoal tile--and not big happy-to-cooperate rooms, either. No, it was a laundry, mudroom, powder room and master bathroom in a continuous run which meant lots of corners, edges, doorways, cubbies and drains.
I made a few mistakes, but I don't think they will be life changers, just annoying to the tile-setter. We are going to pretend that every line is perfectly straight and every tile is perfectly level with its neighbor. If you come to my house, feel free to join right in to that pretend.
I still need to do another washing (the tile is quite a bit darker), but I am finished with the floor tile.
I'm very pleased with how it turned out!
Update: I keep trying to get a good picture of the tile, but it seems like there is always something big in the way...like a person installing doors, or a stack of ceramic tile for the wall, or a pile of supplies that were moved from this place to that, and so on. I guess you'll just have to see it piecemeal.
Here is a bit of it with a sneak peak at what was installed yesterday.
So much floor!