Walls:
1) Studs, insulation, greenboard, thinset, polished porcelain tiles 12x24, grout

Make sure the thinset is a modified thinset.

Floors:
1) Joists, plywood, tar paper, mortar? thinset (modified or unmodified?), polished porcelain, grout.

No tar paper. Either cement board or Ditra. If cement board (I'm assuming 3/4") it can be 1/4", but it must be both thinsetted and screwed down. If Ditra, it must be thinsetted down with a high latex content thinset, and then unmodified to set the tile, just as with the Kerdi.

1) Should I slit the paper side of the insulation prior to installing the Durock so it won't trap moisture once Kerdi is applied?

Or you can use unfaced insulation

2) If I can't find Ditre Set can you recommend any other unmodified thinset that is just as good?

Laticrete 317 thinset, or Mapei's Kerabond.

3) I am installing a rainshower head from ceiling (no tile on ceiling) do you suggest greenboard or Hardie on ceiling?

Greenboard.

4) To level bathroom floor, do I use mortar prior to thinset? If so, how thick should the consistency be?

How much do you have to level it?

Sometimes, I can be numb as a box of rocks! I see what you were talking about now with the mortar on the floor. If this is going to be a mud job, yes, you do use tar paper, but you also use reinforcing wire. Most will use wire lath, but chicken wire is also acceptable This must have a minimum thickness of 1 1/4", and yes, it goes down prior to thinset. As for consistancy, it should be the consistancy of damp sand.

This is a great thread to reference! Can I ask some questions about slight differences in my situation?

1. Shower walls will be 12x12 marble tile. Should I still use modified thinset? Should I use a sealer for grout release purposes prior to installing the tile?

2. I'm on concrete slab. For the area of the floor that's not in the shower, can I put thinset on top of the slab? (Actually, I know I'm going to have to use some kind of leveling material because the floor will probably be very rough after ripping up the tile that's there.) So I guess my question is: can I put the thinset directly on top of the leveling compound if the slab is otherwise in good condition?

First off, the recommendation for the modified thinset was for over the greenboard OUTSIDE the shower. Over Kerdi, you want unmodified thinset. Secondly, with polished marble, there shouldn't be a need for a grout release.

As for your question about going right over the slab, if it's not cracked, yes. There shouldn't be a problem.

ALso, if you think this is a good reference check the one linked below:

Here is a link that might be useful: Mongo's Magnificent Monstrosity!

I think I have it. I am sure we will have more ??'s once we begin but this helps clear up a lot. Now I am off to the store to find the unmodified thinset our local flooring store says they have it. Bill, thanks for the input.

Bill,

Shower floor: Using Kerdi with Kerdi tray
Bathroom floor: Using Ditra
Tile: Polished porcelain 12X24 4x4 (on shower floor)

Need some advice on subfloor. I currently have joists with 1x6 planks as subfloor questions are:

1) Do I need to rip out existing planks and replace with sheet of plywood? If so, what width should the new plywood be? Do we just nail these down on top of the joists?

2) If we have the option of keeping the existing planks do we screw down new plywood on top? If so, what width of plywood? My concern with this option is the height/elevation will not coincide with the existing wood floor leading to the bedroom once the thinset, ditra, thinset and tile are in, I think it will be too high .

I think I prefer pulling out planks and starting fresh but want your blessing. Any suggestions are greatly appreciated.

Thanks again,

L.

Let me ask you first-- How high over the planking is the hardwood?

3/4" over the planking.

Okay. So then we have 3/4, plus the inch (actually 7/8", most likely), so we're up to 1 5/8 overall. The tile and thinset will most likely come to 3/8", so we're back down to 1 1/4". If you're willing to take out the planking, that'll definitely work in your favor. First, a layer of 3/4" ply, then a layer of 3/8" ply, and then the Ditra, and that should put you right where you need to be.

Thanks Bill we are taking out the planking we think it is the best approach for our project then we will begin to layer. Thanks again for your help.

Bill,

Removed all floor planks and installed plywood, glad we chose that option. Will begin the Kerdi application this week. Question:

Can I Redguard my niches (2) and Kerdi the rest of the shower or do you advise against that? I am afraid of all the cuts necessary when waterproofing the niches with Kerdi. My concern is them working together (Kerdi & Redguard).

If I can Redguard the niches would I waterproof the niches first then apply the Kerdi? Please let me know what you suggest is the best approach.

Thanks again for your help.

Use the Kerdi. Two different membranes always create a weak point where they join.

Bill,

1) Tiling the floor with 12X24 porcelain, should we tile beneath the yet to be installed vanity? If so, do you then recommend securing the vanity with screws into the tiled floor and/or walls?

2) Shower floor will be 4x4 what is the smallest grout line I can get away with?

3) When applying the modified or unmodified thinset prior to setting the 12X24's what size trowel do you suggest for such large tiles?

Thanks again for you help.

1) Screwed into the wall.

2) Depends o the 4x4. You're not using wall tile for your shower floor, are you? If not, then go with no less than 1/8"- 3/16".

3) Minimum 1/2"x1/2" notch.

Bill,

I purchased non sanded colored caulking for the bathroom. What areas should we caulk and not grout? I am particularly interested in the inside of the shower and the shower curb both inside and out. Shower is 32X60.

Thanks again,

L.

Caulk all inside corners.