Shower pan questions

[Penderben]

Hello all.

I’m working on a mortar shower pan on a concrete subfloor and I have a few questions.
I’ve already done the pre slope and pvc liner, now getting ready for CBU, mortar bed and curb. Curb is wood framed, the wall framing is all covered in poly overlapping the liner.
I’ll be using Wonderboard Lite, embedded in the mortar with a 1/4” gap at the bottom.

My questions are:

Do I need lathe in the whole mortar bed, or just the curb?

I used Quikrete sand/topping mix for the pre slope (https://www.homedepot.ca/product/qui...5kg/1000166251), is that okay for the pan and the curb?

Anything sound wrong with that plan?

Thanks

[jadnashua]

You only need the lath over the curb.

Since the mud over the curb will be fairly thin, you'll want a different mix. Most people find that the sand topping mix is a 4:1 sand:cement mix, and that a 5:1 mix is easier to work with for the setting bed.

Have you read the conventional shower construction thread in the 'Liberry'?

[Kman]

If those bags are 60 pounds, I would add 25-ish pounds of sand to do the floor. I say 25-ish because that's half a 50 pound bag. That'll bring your ratio to about 5:1 sand/cement.

For the curb, I'd mix it as bagged.

[cx]

I believe the Sand Topping mix is about a 3:1 sand/cement mix, Ben. Way too rich to use effectively as deck mud/floor mud/dry-pack. You'll want to dilute it some with sand, as Kevin suggests, to make it more workable.

For the curb you'll not find the Sand Topping very useful at all. You'll really want a mix with some lime in it, such as a pre-bagged Mason's Mix or Mortar Mix from the same manufacturer.

My opinion; worth price charged.

[Penderben]

Thanks for the replies everyone.

So the topping mix should be okay for the pan diluted with some sand; why is that? Just curious why a more cement heavy mix would be a problem, I would just think it would be stronger? No argument, you guys know, I’m just wondering why :-)

Would this type-s mortar mix work for the curb then? https://www.homedepot.ca/product/qui...5kg/1000166242

Should I do the curb before or after the floor, since they won’t be the same material?

I’ll have to check out the how to in the ‘Liberry’, I’ve been searching the forum and the great internet but some how missed that section.

Thank again

[Penderben]

Well, the Liberry looks to have answered those questions
:-)
It appears I want to do the curb first, and the type-s mix should be fine.

[jadnashua]

The more cement, the stickier and denser the mix becomes. For ultimate strength, that might be okay, but it is much harder to form and all that extra cement making it denser also means that it will take much longer to drain. Water WILL get to the setting bed in a conventional shower, and you want it to be able to drain to the weep holes, rather than sit in the pan.

[Davy]

What Jim said, You want the water to travel thru the mud bed and hard dense mud won't allow that to happen. If I don't already have some sand on hand, I'll grab a few bags of all purpose sand and a bag of portland cement and measure my own at 5 to 1. Mix it dry, then add water slowly till it looks like this.

[Penderben]

Thanks for the answer