Installing tile in bathroom - Any tips?

I'm doing a remodel in my small guest bathroom. I've pulled up the existing flooring (vinyl sheet on 1/4" underlayment) and put down additional 5/8" plywood to bring the subfloor up to snuff. Next I will be installing Ditra, and finally 12" ceramic tiles on point.

Do I need to do anything special to seal the subfloor off to protect from a leaky toilet or tub/toilet overflows? I'm looking at the cutout around the toilet flange and thinking that if the toilet seal ever leaks, I will have water under the tile which seems really bad. Also, if the tub or toilet ever overflow and it gets to the wall it could do the same thing.

Most people never have a problem and don't waterproof their floor. But, if you're using Ditra, you could get some KerdiBand and go around the edges, but there's still the problem with the doorway...if you contain any (large) spills in the room, they'll still go out the door. You'd also have to band any seams in the Ditra. Waterproofing up the tub skirt is problematic, too although you could caulk there. If you're worried about it getting beneath the tile around the flange, you could use some KerdiFix to seal around that area between the DItra and the flange.

If the toilet leaks, it probably wasn't installed properly. When reinstalling the toilet, ensure it doesn't rock (shim if it does BEFORE resetting and installing the wax ring), and then tighten down. Unless you regularly have water fights in that room, generally, don't worry.

Maybe I'm worrying too much about it. I'm going to try a wax free seal, and get a buddy to help since I've never set a toilet before.

I'm guessing I can find some kind of shimming kit at Lowes?

The height of the flange may be a problem as you have raised the flooring. The flange should sit ontop of the finished floor. Now would be the time to determine if it needs to be raised.

The big box stores sell composite shims, often in the door/window area. Personally, in those I've installed, I just use various coins...I've got them in my pocket, don't have to make a trip, and they come in various thicknesses. I've used the Fluidmaster waxless seal. Best if you don't follow their instructions and install it on the horn of the toilet, then set the toilet down onto the flange. Their cardboard ring is hokey. If the inside of the pipe is clean and smooth, they work fine. They do cost about 5x more than a simple wax ring, which also works fine. As mentioned, the proper place for the flange is on top of the finished floor. If yours is recessed very far, the waxless seal will work, but otherwise, replacing it in the proper position or adding a flange extender ring is a good idea.

Also, you might want to look at one of the tile leveling systems: Tuscan Leveling System (a bigger investment since you have to also buy the special tool), or the QEP system, which HD sells. These will help you get your tile set perfectly level with each other faster than you could normally do it yourself.

The new floor will be about 3/4" taller than the old. Not sure if that is considered a lot. The flange is mounted to the existing subfloor, so below the finished floor by 5/8" plush the thickness of ditra, thinset, and tile.

The finished floor would be the top of the tile, you will have over an inch gap. Raise the flange!

Yes, raise the flange. I would suggest have a plumber do it since you admit you are a total novice at installing toilets. Basic toilet installation is quite simple, but you have a serious problem with the flange height. True, you can try to DIY, but if you screw it up, you will end up with the total job ruined and having to be redone. Shimming should not be needed unless the floor is not level, but absolutely do not try to make up an inch or more space with wax or waxless seals. That's way, way too much.

Thanks guys; I've been looking at replacement flanges, and access below the floor is good (storage room). I may try it myself.

Great advice men.

The number on failure of a Ditra install in the bathroom I have found is the toilet connection.

As mentioned the toilet flange should ideally sit on the finished tile. This point really should be outlined in the Ditra instructions.

There are pieces you can buy to raise the flange from your plumbing wholesaler but not a full inch I think.

JW