The bathroom floor is going to be tiled with the same tiles that we are using on the walls in the shower.  The floor of the bathroom was originally done with a thick-mud bed over a wire lath.  Since I’m fairly certain I didn’t have the skill to do that, I’ve done what is much more common these days, and that is to lay down some Durock over some plywood.  This gives a nice flat base without alot of skill required.  To keep everything in place, I first screwed down the plywood to the plank sub-floor (trying to get the screws into the studs as well).  Then I put a coat of thin-set over the plywood, and laid the Durock on top of that.  The picture above is just a test fit, so there is no thin-set in that (but check out the gallery for those pics).  I once again used my jigsaw with an old blade to cut the Durock, which works wonderfully, if a bit messy.  Cutting out the part for the toilet drain was a bit tricky, as I didn’t want to just cut out to big a section for fear it would destabilize it.  After test fitting the pieces and laying the thin-set I then laid the sheets down, and slid them around a bit to get them to bed into the thin-set well.  Then I screwed them down using Rock-On brand cement board screws, which work wonderfully for securing the Durock.  Lastly I used some fiberglass tape, and some more thin-set to secure the seams.