I recently did just as you're doing; I'm a DIY'er so take this with a grain:

http://www.billbblog.com/Diy/33/Build-Shower

1. I'd leave a gap; 1/8"/
2. yup. (On floor)
3. I'd do expanded.
4. Nope.
5. CBU. I'd say hydro not necessary.
6. You'd be fine with the 2x4's covered with CBU but to be more anal, make a sandwich of CBU strips.

Have fun.

Bill

if you membrane the ceiling you almost have it ready for a steam shower.

if you use CBU for the sill, it can be extremely thin (narrow); some people like that.

Bluedots you didn't write anything about the slope going down to the drain. Slope first, then membrane. Mud for slope.

1.Hang CBU. Should this come all the way down to the subfloor or should there be a gap? Which type of CBU do you prefer: Durock, Hardie or other?
CBU taped and mudded with thinset - what thinset would be best for this? Prefer to stick with Laticrete products.

Being that you're using a topical waterproofing, it's fine to go all the way to the subfloor. The only reason for keeping it up is when you're using a standard pan membrane that goes UNDER the mud bed, and you want to make sure that the bottom of the cement board won't be able to wick water up and pover the top of the pan membrane. But in this case, that's not applicable. As for preferred cement board, ask a dozen tile guys and you'll get a dozen different answer. Mine is Durock, but they're all good. Concerning taping the joints, I normally won't tape them in the standard way of thinking. What I do instead is use the 6" cloth made for the corners, and embed it in the Hydroban over the seams. In fact, I just downloaded a pic of a shower I did last week so you can see":

2. Slipsheet of roofing felt - stapled

Doesn't need to be stapled, just laid in place.

3. Expanded diamond metal mesh or metal lath (which one?)- not anchored

Two different names for the same product-- expanded diamond mesh wire lath. :-)

4. Then setting the drain and mud. We've watched the Schluter video of setting the Kerdi drain in the mud bed - since we'll be using Hyrdoban is there any difference in the way the drain is set - aside from the fact that you don't put the Kerdi on top ;).

No difference whatsoever. IF you're looking for Laticrete's 25 year warranty, though, you want to make sure you're using their 226 fortified thickbed mortar, instead of using a standard sand mix for the mud bed.

5. Ceiling will also be tiled. Was planning on using drywall for ceiling (Should we use CBU?) - should that get a coat of Hyrdoban as well or no since the ceiling is not a wet area?

By spec, this can be drywall, even if it's tiled. But I prefer, if I'm going to tile the ceiling, to Durock it, and no it doesn't need to be Hydrobanned. In fact, you only need to go up to the level of the showerhead, as shown in this next pic of that same shower:

6. Shower curb - are 2X4's covered in CBU and then the Hydro ban acceptable? I've read SO MANY differing opinions on this!

Absolutely. Moisture will not get at the framing with a topical waterproofing, and if it does, then the framing's the least of your worries! :-)

One last thing-- To David's comments--

if you membrane the ceiling you almost have it ready for a steam shower.

With Hydroban, that's NOT an accurate statement. Hydroban is a terrific waterproofing, and for that reason, the perfect product for this application in a standard shower. It is NOT, however, vapor proof, which it needs to be for a steam shower.

Bluedots you didn't write anything about the slope going down to the drain. Slope first, then membrane. Mud for slope.

This is just like a Kerdi shower, where the membrane is topical, and therefore there is no "preslope", under the membrane then a "slope" over-- it's all in one, under the membrane.

Even after reading here for several years, I continue to be amazed at how kind and generous with their knowledge people on this forum are!
Bill G. - Thank you, thank you for your blog! It has been EXTREMELY helpful! Can't wait to see how your bathroom looks when its all done!
Bill V. - Thanks SO much for the detail in your reply. It did lead me to a couple of other questions (of course! :) )
Mud bed- I bought the Laticrete 209 mud (no additives, did not buy the additional optional additive) as I was under the impression from reading over at John Bridge that you wanted the mud bed to be just cement and sand. I would like to know that Laticrete is going to stand behind the Kerdi Drain/Hydro Ban combo (one reason I chose this combo). So do I need to take this mud back and get the 226? Does Laticrete have a spec/instruction sheet on Hydro ban/Kerdi drain so I don't make any mistakes? Will the fact that it's fortified make it harder to work with?

The place where I bought the Hydro Ban does not sell the Laticrete fabric. The guy their called the Laticrete rep while I was standing there to ask about what to do at the change of plane from mud bed to wall - the rep told him we should just do a bead of caulk in that change of plane and then hydro ban right over that. The rep said not to worry about the fabric with the hydroban at all. Does this sound right/reasonable to you?

THANK YOU so much for ALL your help!

I picked the hyrdoban b/c I thought it would be more user-friendly than Kerdi but now I am starting to wonder :) Oh well, the CBU is up so no going back now.

Humm. I didn't see anywhere on the Schluter site that says to use modified deck mud. I didn't for my install - hope it lasts. Maybe I should have known that a modified product is used when embedding plastic.

Shluter has a good video showing a mud pan/Kerdi drain intall now; I think it's new.

Bill

That's because it's not a Schluter spec. If you're going to use Hydroban instead of Kerdi for the membrane, and expect Laticrete's 25 year warranty, it had better be a fortified deck mud.

OH, OK. I clicked a link on the Laticrete site labeled 10-yr warranty which listed some thick mud products, including 226, 3701 and not 209.

So quick question for Bill V. : 226 has a psi of 5500-6500 and I've read that a 5:1 deck mud is about 3k psi. Warrany aside, (it is what it is), does that sound right and in your experience does the 3K product hold up well, assuming a solid floor and proper underlayment. If there are just too many variables to comment, I understand.

Thanks,

Bill

Yes, it does, if mixed properly. I've been using normal drypack from the time I started in the trade till just this year, and never had a problem with it. The only reason I've switched from it is for the warranty.

The place where I bought the Hydro Ban does not sell the Laticrete fabric. The guy their called the Laticrete rep while I was standing there to ask about what to do at the change of plane from mud bed to wall - the rep told him we should just do a bead of caulk in that change of plane and then hydro ban right over that. The rep said not to worry about the fabric with the hydroban at all. Does this sound right/reasonable to you?

The change from mud bed to wall should be not have a gap, so I'm thinking that comment about caulking is misplaced. Far as I know, you use laticrete fabric over joints greater than 1/8" wide and there really should be no such gaps in your install - at least that's how I did mine. Gaps between CBU sheets were closed with mesh tape and thinset. There were no gaps between mud floor and wall, as the wall CBU sheets were installed before I put the mud pan down. I bought a roll of Laticrete fabric but never used it. I think this makes sense.

Bill B.

I don't like the use of thinset prior to setting tile because it tends to leave "speed bumps" in the walls that you DON'T get embedding the fabric in the waterproofing membrane, instead. At times when I'm NOT doing a hybrid shower, I'll use self sticking mesh tape, and then embed it in thinset when I spread the thinset to set the tile, thereby avoiding the "speedbumps".

Yes, I still don't quite understand this notion though.

Is there a thinset thickness or trowel size that is considered large enough to hide speed bumps? If you're putting on more thinset it seems you'll have less trouble with speed bumps broadcasting out to the tile surface.

I'd read read about the speed bump issue and was concerned about it but I'd also read that it was a good idea to tape the CBU joints as it is how the CBU manufacturers say it should be done and there are warranty issues involved. Not sure that's valid though; how does a warranty from one manufacturer relate to that of another?

I'd read some guys do both, thinset/tape and Hydro/fabric, for overkill and when in doubt, to make sure the CBU and Laticrete warranties would be valid.

The shower I tore out had cracks in the tile where the CBU edges were because the CBU had neither been taped nor backed with blocking, so that was weighing on my decision to do the thinset taping; it just seemed to me that the thinset/mesh tape would make the install stronger.

Turned out, my taped joints were probably only 1/16" high, which were buried and lost in my medium bed thinset, (large 18" x 18" tiles), which was about 3/8" thick.

Is there a thinset thickness or trowel size that is considered large enough to hide speed bumps? If you're putting on more thinset it seems you'll have less trouble with speed bumps broadcasting out to the tile surface.

True, but depending on the tile size, you then run the risk of the tile plane not being flat (as some tiles might bed into the thinset just a bit deeper than others), as well as way too much thinset purging up through the grout joints. Why waste the material and take a chance on the quality of the installation when it's not necessary at all?

...but I'd also read that it was a good idea to tape the CBU joints as it is how the CBU manufacturers say it should be done and there are warranty issues involved. Not sure that's valid though; how does a warranty from one manufacturer relate to that of another?

There is no warranty issue whatsoever. So long as one panel is brindged to the next, your warranty is intact. If you're using mesh tape, it doesn't matter to the CBU companies whether you embed it when you tape, or embed it when you set your tile-- so long as the tape is thinsetted to both panels whose joint is spans. With respect to the Hydroban, using the cloth will still do the same thing, while reinforcing the waterproofing at the same time. A win/win situation.

Yea, I didn't mean that taping while setting tile or before might be considered different.

Starting to get a little off topic here but I definitely used too much thinset to tile. The tile literature said to use a 1/2" trowel, rounded, which I did, (anything over 15x15 it said). Then I'd read that you need to back butter large tiles, which I also did; maybe 1/8". The resulting amount of thinset was difficult to manage for this beginner.

Bill, how would you set 18" x 18" porcelain tile that was very flat, (I put a straight edge on them and laid them on my quartz kitchen counters to check), with a waffle pattern on the back, on shower walls that were flat, square and plumb? Would you back butter and what trowel?

Thanks...

One the walls, I'd use a 3/8x 1/4 notch to spread the walls, and then flat trowel and fill the back of the tile (for 18x18, using Laticrete 4XLT-- the large format versioin of 255).

One thing about the speedbumps-- they become even more important to avoid with large format tile, because the can really get an edge sticking way out, and then you DO need the larger notches. Other than that, with flat surfaces, the only time I'll go to the larger niotches for large format tile is if I'm setting them on the floor, and then 1/2x1/2 is the SMALLEST notch I'll use, and then I'll also make sure to back butter the tile. I prefer to just use a 1/2x3/4. They're not usually necessary on walls, though.

OK, thanks, Bill, for the pointers.