General Tile Discussion

This is a basement shower. I broke the 3 piece drain removing the old shower so I had to break up the floor and I added a new stub with a 4" PVC surrounding it as per a Schluter video. My question: Do I need a shower pan liner if I am floating the pan and using Schluter Kerdi membrane? (Guy at the Tile shop said I needed to put a liner behind the backer board. I thought if I was using the membrane the liner was not necessary.

Plan:

1. Finish the pony wall (half wall, whatever) and curb. 2. Use fast set mortar to permanently set the drain flange.

3. Put a thin coat of unmmodified thin set on the slab to promote adhesion of the dry pack. 4. Float the pan using strips of Kerdi foam as screed guides. (I could not find dry pack anywhere other than this Mai Pei stuff that was like nearly a buck a pound. I got a 55lbs bag of portland cement and 4 50lbs bags of all purpose sand for less than $20 total)

5. Follow the directions for the Kerdi membrane and waterproof everything and using the overlap/tape/everything in the kit seal everything.

From there I plan on tiling the floor first and then doing the walls as fast as possible after the floor sets and I cover and protect it. I have everything mocked up in the garage with the spacers so I kind of hope that I can do most of my cuts ahead of time and move the tile down to the basement and number them in a way I know how they go. Other relevant information: 1. The 2x4 in the foreground is just there for measurement purposes. I am going to put a short wall to separate the shower from the toilet and plan on a low curb. 2. I furred out (is that the right term?) the walls by ripping a 2x4 into furring strips. I used the method Issac had in one of his videos where he used the laser and 4" away from the wall and figured out how out of plane each stud was. In the same video he also talked about metric. I bought a metric tape measure and you can possibly see the numbers on the studs in one of the pictures but I put the laser 10cm (100mm) away and just measured millimeters out of plane. Su much easier. 3. I am going to do the shower pan float with training wheels method with the Stud pack modification. Instead of using temporary guides for the screed I am going to use Kerdi foam along the edges to give me a level edge to screed off of that I can just leave in there.

(useless back story) I am so sorry if this is a redundant post and also apologize for being a newbie DIYer. Basically, as Issac has stated in his videos, tile setters are hard to find and the good ones are booked out for years. An old family friend that is one of the latter types of setters suggested I give this a go and suggested I go to the Tile Shop. My wife and I fell in love with the Tile Shop and I'm an engineer and home renovation is my favorite thing to do besides ski. Anyway so this is a basement bathroom and one of our 3.5 baths that was not really used much so figured all bathrooms need to a remodel so it was worth learning. (/useless back story)