How thin to float mortar bed

[Donnie McCool]

John,

I am re-tiling my basement shower.I just finished tearing out all the old tile and re-tiled the upstairs bath :a huge shower,around the bathtub,floor and countertop.I did 12''diagonal on the floor and 6 '' and mosaic everywhere else.I am very happy with the results. I used 3 tilebooks one of which is by your friend David Byrne.I consider that one the "Bible" Ended up using Daltile Continential Slate porcelan tile which I love.I really love tiling and would do it for a living if I weren't so slow!Anyway..back to the basement.

I believe my house was built in the 60's.I have limited height in the basement due to drain lines running above my shower space. I tore down to sloped concrete with a drain but I don't think I can use that because there are no weep holes.Just the bottom half of the old drain.I understand I need a drain with weep capability.so I am setting up a new drain assembly, floating a new sloped surface,CPU,mortar bed, then tile.So my question is:how thin can I float the 2 concrete sections? Right now I'm looking at 84" from floor to joist before I do anything.I am 6' 2" so it's going to be kind of tight.If I float each to a couple of inches or so I'm going to be hitting my head on the ceiling. Can I float the 2 sections around 1" each if I add some kind of additive to the concrete? I am using Quickcrete Sand/Topping mix.

Enjoy reading your forums.Thanks, Donnie

[Mike2]

Hi Donnie.

Over a slab you could get by with 1/2" at the drain for the pre-slope. Deck mud gets bonded to the slab with thin set mortar. Then for the final top layer I'd plan for 1-1/4". When all is said and done, that should give you a net clearance in excess of 6' 9" at the drain.

Not much jump room for sure but outta be enough for a little peroette spin thing.

[Donnie McCool]

Mike,

Thanks for the advice.I'm now just actually doing the work! You say I should slop down a good layer of thinset between concrete slab and preslope mud? You think some Redgard Waterproofing(spashed on the slab while I was doing the concrete walls-I'm going to tile directly to the block.I was told that would be a good waterproofer plus a good surface to tile to) will hurt anything as far as the bond between slab and preslope?

Thanks, Donnie

[Donnie McCool]

I want to create my own corner shampoo and soap shelf in my tiled shower(already finished) I was told to use stainless steel "L" brackets to mount the tile shelves on,actually to set the shelfs on,that the caulk will secure the shelf.

Problem is,I can't find any stainless L brackets.What else can I use that will look good and hold up well?Is chrome fine as long as I wipe it down regularly?

Thanks, Donnie

[Davy]

Donnie, there is no need for Redgard under the preslope mud. Just a slurry of thinset to bond the new mud to the slab.

[koihito]

Try looking at a Better Dish, It will look much better than brackets.

[Donnie McCool]

There's already Redgard on the slab that I accidently slopped on there.Will it hurt anything?

[Donnie McCool]

I'm not familiar with Better Dish.

[Davy]

Donnie, thin drops won't hurt anything.

[Donnie McCool]

Thanks Dave.

I'm going to get at it tommorow morning. I've been slaving trying to get the 2-piece pvc drain as low as possible to maximize the distance in my cramped shower space. Tommorow I will put some thin set down,pack the deckmud in for the preslope.Let it dry,then to the rubber pan.I am attaching it to concrete block on 2 walls so I am a little concerned because I know it will stick out where I fold the corners.But I can't wait to get all the preliminaries done so I can start tiling.I love tiling!!!