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Discussion Starter · #1 ·
How much Portland cement and sand do I need to mix to complete a 48" x 31" shower pan with a 48" curb? I'm doing a Laticrete membrane so there won't a be preslope level (i.e. all the mortar will go in at once). The height of the mortar at the drain will be 1-1/4", and the curb will go in on 3 stacked 2x4s.

I just want to avoid running out before the job is done.
 

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Tileguy
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You should use two different mixes, Sand Topping Mix for the floor and mortar mix for the curb. The mortar for the curb needs to contain lime which makes it sticky.

Your pan is 10.5 sq. ft. and I'll guess the average thickness will be about 1.6"

#60 = .50 cu. ft. = 6 sq. ft. @ 1" & 3 sq. ft. @ 2"
#80 = .66 cu. ft. = 7.8 sq. ft. @ 1" & -4 sq. ft. @2"

You will use about #200, so 2 @ 80 + 1 #60 or just get 3 #80. It's cheap. One bag of mortar will be plenty for the curb if you go that way.

Ever do this before?

Jaz
 
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Tileguy
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HUH? I wonder if the geek got this?

Jaz
 

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Discussion Starter · #4 ·
I'm here Jaz. I was busy last night installing Durock (bathroom reno is my 2nd job).

My understanding was I needed 1 part portland cement, 1/2 – 1 part powdered masonry lime, and 4 parts sand for the curb. I also read that stucco base coat works well too. Ever use that?

Yes this is my first mortar pan. Doing home improvement at night is the only way I get out of doing dishes...
 

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Tileguy
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There are many variations to the recipe of "fat-mud". People have their own preference and they work. Your recipe is fine, others like more sand and lime such as; 1:6 + 1 lime, even 7 :eek:sand. Yes, stucco base, (I think it's also called brown-coat) is very similar too.

I didn't realize you were gonna mix from bulk. What type of sand will you be using? Be sure to mix by volume, NOT weight. Sometimes the two are close, but many non pros make the mistake of weighing the ingredients. We don't use no stinkin scales on the job.:laughing:

Jaz
 

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Tileguy
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Sand Topping is usually 1:3, It'll work fine as is, just harder to work with. We usually add some washed sand. Take a guess how much to add. For the shower floor, a 1:4 is the ideal mix, but 1:5 or even leaner will work fine too.

Jaz
 

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Tileguy
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I would say yes it matters.

How you gonna work in the shower without damaging the curb? The curb is always last.

Jaz
 

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Discussion Starter · #10 ·
Ok Jaz...the pan is in. And just to clarify, I wasn't talking about putting the curb in before the pan on the same day...I knew I wouldn't have time to do both so I was considering which I wanted to do first.

Anyhoo, I just want to make sure I understand this whole modified vs unmodified thinset issue. So tell me if these statements are true:

1) I need to use unmodified thinset in the shower because I'm installing onto a topical membrane.
2) I need to install hardiebacker to the bathroom floor with modified thinset because it sticks better to plywood.
3) I can use either to attach floor tile to the hardiebacker, but modified is probably better.

I know you're going to miss me when this bathroom gets done...probably some time in October.
 

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Tileguy
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Hi,

1. NO, well kinda. If you're still using Laticrete stuff, I think they say modified, but go check. I don't think you ever said how the walls were being waterproofed? But I didn't re-read this whole thing. If it was Kerdi, you'd wanna use unmodified for over wallboard or CBU. So, what are you going over and which membrane?

2. Yes & No. Hardie says you can use either. Technically you do not have to stick any CBU to the floor. The mortar holds the board up, and the screws/nails hold it down. But yes, modified bonds well to ply and OSB where unmodified does not.

3. No. Sure, even unmod will work, but Hardie wants you to use modified and why wouldn't you? It's better in most cases.

4. Oh, there is no #4.

I know you're going to miss me when this bathroom gets done...probably some time in October.
You wait 'till you get my invoice! :wink:

I'm gonna be out your way soon for a visit. Maybe I'll hand deliver the invoice?.....

Jaz
 

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Tileguy
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Hey no problem. My address is 1600 Pennsyvania Ave. Just let yourself in!
Good One! But sorry, I'll try to visit in a couple years.

Jaz
 
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