The last three days of the bathroom transformation have been full of lots of odds and ends.  The first thing I had to finish up was pouring the shower curb.  
When building a shower curb you need to keep in mind that building code requires the top of the curb to be at least 2 inches higher than the floor of the shower.  So that means the top of the curb after you put the mortar on it should be at least 2 inches higher than the floor you just poured (since the thickness of the tile on the floor and the curb will be about even).  My curb is built out of 3 stacked 2x4s and because my floor is only about 1 1/2 inches thick (plus another inch in the pre slope) I had plenty of room.
To pour the curb you first wrap the curb in wire mesh, making sure NOT to tear or puncture the liner.  You don't attach the mesh anywhere but on the outside of the curb, but by bending the metal it holds itself in place:In the previous photo you can see the missing tile on the floor (and the stain on the floor) where the former longer, wider knee wall extended into the room.  Here is a photo I showed previously where you can see the footprint of the old wall before I removed the tile:
I was able to match the grout color using a small piece I chipped out.  I made up a small batch of grout and pushed it into the seams using a foam float:

After wiped down with a sponge it was clear I had the right color grout:

Finally, when it was all dry it is was nearly impossible to tell which tile was the patch job:


Budget for this part of the remodel: $77.07Mortar Mix: $12.06Metal Mesh: $8.15RedGuard: $44.623/4 inch roller cover: $3.77Floor Grout: $8.47

I settled on Hardibacker 1/2 inch since it was supposed to be the lightest weight cement board on the market.  But those suckers are still really heavy.  I actually had to have hubs help me hang them.  A couple quick tips working with cement board.    
1. NEVER use green board, drywall or any sort of wood as a substrate for any area of your bathroom that will be wet.  Cement board or poured cement is the only thing you should using.  You can use other products in "damp" areas (like the rest of the bathroom) but never use them anywhere there will be direct contact with water. 
2. You need to score and snap cement board. You should not use any sort of saw on it since that will kick up toxic dust, not to mention chew through any sort of saw blade. To score it you ned a very sharp utility knife and you want to just keep going over and over the cut line until you can easily break the board cleanly.  It is NOT anywhere as easy as snapping drywall. 
3. When attaching cement board to the walls you must use special screws designed only for cement board.  The hardibacker required a screw type that actually had a square head.  In the box of screws they also provided a drill bit for use with the square heads.  I needed my power driver to get the screws to lie flush with the cement board, you would not be able to drive those screws in by hand.  They should be into the studs, no more than 7 inches apart. 
4. 1/2 inch Hardibacker is NOT actually 1/2 thick.  If you need to abut it to 1/2 drywall it will not be flush.  You need to shim behind it, on the studs, to make the wall flush.  You will eventually tape and mud the seams and also have a chance to feather out the difference in height, but a smaller gap is always better. 
5. When installing cement board you want to leave at least 1/8 inch seams between the boards (for expansion if they ever get wet.)  Getting super accurate cuts was pretty hard for me, so leaving the gap was no problem. 
6. Make sure you leave a 1/2 inch gap between the bottom of the cement board and the PVC membrane.  You are eventually going to bury the bottom few inches in your final cement shower pan, but you wan to leave a gap so any water can run out of the bottom of the cement board.
7. NEVER EVER EVER secure the bottom of the cement board with screws.  I marked where my liner ended and that was the first point from the bottom that I screwed into the cement board.
Here is what my shower and knee wall looked like once I added the cement board:
I did use a drill to cut out the holes for the plumbing fixtures, but the rest of the cuts were all made by scoring and breaking the boards. After the board is hung you need to tape and mud the seams.  DON'T USE DRYWALL SUPPLIES.  You must use special alkali resistant cement board tape and mortar. It is easiest to just use the same mortar you are going to use to set your tiles.  (In my case I am using a mortar specifically for travertine.)  You can see the tape in the upper right corner of this photo: 
I also used mortar to repair the damage to the green board behind my roman tub.  If this were a "regular" tub I would have pulled all the green board out (since it is NOT good to use on a tub) and replace it with cement board.  However, since this is a roman tub and is so deep, and it is so infrequent that water comes in contact with the walls around it, I decided to forgo the time and expense of replacing it.   If you were to install a hand held sprayer or anything else that could possibly lend itself to excessive splashing, you would definitely want to use cement board:

Once the walls were repaired, it was time to finally finish the shower pan. I talked a little bit about how you build a shower pan correctly in my last post.  This was just the final step.  I used this mud calculator to figure out exactly how much deck mud I was going to need for the final pan.   It turns out I ended up needing 40 pounds of portland cement and 200 pounds of sand.

Needless to say I needed help with this step because my mixing pan wasn't large enough to do a batch that large.  I had to mix three smaller batches.  Because the set time was under an hour for portland cement, I had hubs make the mix, while I spent the hour packing and leveling the deck.

I didn't get a lot of pictures of this process, but when all was said and done, this is what my final shower pan looked like:
The dry pack mortar (or "screed")  was so much easier to use than the mortar mix I originally used for the preslope.  At this point you could also pour the curb, but I knew I would probably mess up my soft shower pan if I tried it, so I let the cement cure the recommended 24 hours before tackling the next step. If you ever want to try it yourself and want a little advice, I encourage you to check out the John Bridge tile forums.  They are so much better than any other DIY website for the subject of tiling.  I actually have become a little addicted to reading them.. they are like a tile lover's Pinterest.   I think it may be a sign that I have become obsessed with this project!! 
Next up: Finishing the shower curb and waterproofing.   Budget for this part of the remodel: $103.23Cement board (5 sheets): $57.35Mortar Mix: $21.63Hardibacker Screws: $7.86

Cement board tape: $6.41

All Purpose Sand: $5.64

Portland Cement: $4.34

Renovation to date total: $224.91

Diagram courtesy of Oatey

I also installed the drain at this point (not pictured, but shown in the diagram above.)  I used a specialty drain which is intended for tile floors which is adjustable in height and includes "weep holes" in the housing to let any moisture trapped in the cement floors to make its way to the drain.  I had to cut the ABS line (ABS is similar to PVC but it is black in color) that previously ran to the pre-fab shower pan, and the glue the new drain to the pipe using ABS glue.

The next step is to pour the "preslope" or the mortar floor below the liner which MUST BE accurately sloped in order to drive water towards the drain.  Although water will never come in contact with this layer (since the PVC liner will go over the top of it) it must be 1/4-1/2 inch higher for every foot between the edge of the shower and the drain.  

I will make a confession.  I really struggled with this step.  I used mortar mix to pour the base layer and had trouble getting the slope correct the first time.  I spent an entire day ripping out the cement from my first attempt and re-pouring the preslope.  This set me back a full day. 

What I learned from this fiasco was that I should have used "deck mud" (a 1:5 ratio of cement to sand) instead of the pre-bagged mortar mix (which has a much lower ratio, closer to 1:2.)  I will eventually pour the final shower floor using the deck mud mixture, since it was 10 times easier to work mix.  The sand slows the set up time as well as make the mixture more malleable. For more info about deck mud, see this great post.

After allowing the preslope to cure overnight, I was able to add the shower pan liner.  This PVC membrane is available, by the linear foot, at most big box hardware stores.  You want to leave AT LEAST 6 inches up the wall and NEVER EVER EVER put a hole in it.  The liner is nailed at the top and outside of the wet areas only.  It is not held in place at the bottom of the shower or around the curb by anything other than the cement that is going to be poured over it. 
 You do have to notch the corners to get around the curb, and you deal with these cuts by using premade corner patches which are held in place by a special PVC liner adhesive.

Once the liner is in place you must carefully cut out around the drain.  I made sure to leave little notches which lined up with the weep holes and made sure the bolts holding the top of the drain in place were well sealed:
And now the moment of truth.  The leak test!! You have no idea how much I was sweating this step.  You fill the shower pan with water up to the edge of the curb and let it sit for 3 hours.   You don't want to see any leakage which would indicate a tear, bad corner patch or flaw around the drain.    It is hard to see, but in this photo the pan is full of water..and turned out to be LEAK FREE!!! Hurray!

When I last posted, I had just completed demo on the master bath shower.  The demo revealed that the floor was only 5/8" OSB and because I was planning on putting in a lot of weight in tile and a poured masonry pan, I knew I had to reinforce it. 
This is what it looked like after demo:
And after reinforcing it: 

An unintended consequence of changing the size of that half wall was that it left a scar in the flooring. (you can see how much smaller the knew wall is going to be):  
I popped out that one tile

And luckily the previous owners left an extra box of these tiles in the garage, which will make for a simple replacement:
The last thing I did in this stage of the shower re-build is line the shower pan with roofing paper. This will act as a moisture barrier between the plywood and the sloped mortar floor that will go in next.  
Lastly I stapeled down metal mesh.  This will give the mortar mix something to stick to.
And that is what we are left with.  
The next two days of the project will involve pouring the first layer of a masonry shower pan.  We are getting there little by little. 
Budget for this part of the remodel: $48.71Plywood (for subfloor): $19.542x4s (for knee wall): $9.31Roofing Paper: $11.71Metal Mesh: $8.15
Renovation to date total: $48.71