Bathroom Floor remodeling

Hi All,
I've taken on a personal home improvement project to completely remodel the down stairs 1/2 bath and put in 12" x 12" ceramic tile. When we bought the house the previous owner had installed oak hardwood flooring through out the entire first floor including the half bath. After I ripped out the toilet and hardwood floor I was not surprised to find water damage on the sub flooring around the toilet and a rusted toilet flange.

So far I've replaced the damaged sub flooring (5/8" OSB to match the existing sub flooring) and removed the rusted out toilet flange. So now I've got two quick questions.

1) Is there any consensus on the use of Hardibacker board or Durock as the backer board to install the tile over? And a follow on is there a consensus on the use of 1/4" or 1/2" thickness other than for purposes of maintaining transitions between new and existing flooring?

2) When I install the new toilet flange should I install it on top of the backer board or on top of the tile? I'm aware that I should tile underneath the up to the waste water line hole in the floor but unsure if the flange should go on the backer board or tile?

Any help / guidance would be appreciated

1) Is there any consensus on the use of Hardibacker board or Durock as the backer board to install the tile over? And a follow on is there a consensus on the use of 1/4" or 1/2" thickness other than for purposes of maintaining transitions between new and existing flooring?

Either/Or. Neither offers any structural benefits over the other. Both offer a fine "tooth" for the thinset to bond to.

2) When I install the new toilet flange should I install it on top of the backer board or on top of the tile? I'm aware that I should tile underneath the up to the waste water line hole in the floor but unsure if the flange should go on the backer board or tile?

Again, Either/OR. On top of the tile would be preferable but either way can work.

Thanks Bud! No wonder I can't identify a straight answer anywhere on either of these items. I'f I'm going to put the Flange on top of the Ceramic tile can I just use a Masonry bit of the proper diameter to drill a hole through the tile to screw the flange down into Sub flooring through the backer board?

Typiclly the stool attaches to the flange only.

5/8" OSB makes me nervous personally I'd add another 3/8" minimum and would use Ditra instead of CBU (I believe Ditra minimum is 3/4")

I think Bud confused what you were saying about the flange - yes it will be a pain to drill through the tile (much easier to install it above the backerboard and not have to drill through tile IMO) but a properly sized masonry bit and some water/3 in one oil should get you through.

(I believe Ditra minimum is 3/4")

Actually DITRA minimum is 5/8". Don't know why it would make you nervous if it is approved and warranted by Schluter.

I think Bud confused what you were saying about the flange

WRONG AGAIN MIKE! Go back and read my comment. What did I say?

I said:

Either/Or. On top of the tile would be preferable but either way can work.

How can you construe that as "Bud misunderstanding". Check your plumbing specs my friend.

Just wanted to add a status update. Due to a little movement in the floor while working on it I decided to add on an additional layer of 5/8 OSB on top of the Sub Floor then installed 1/4" Hardibacker onto that. Bathroom floor height will be about 7/8 of an inch higher than the adjacent hall, but I figured I can work a threshold and make that difference "disappear"

I wasn't planning to use DITRA as I can't acquire it as easily as Hardibacker. However I'm seriously contemplating it when I re-do the kitchen flooring. With 16" OF Joist spacing and a 5/8" subfloor I'm within the recommended range for DITRA and the thinner membrane will be much easier for me to handle the transition to a carpeted room directly adjacent.

Any recommendations on working with DITRA over Hardibacker?

DITRA is available at all Home Depots if you have one in your area. Otherwise it can be purchased online at several places. One place is:
http://www.tile-experts.com