I am building a shower pan. It is 36d x 30w. I am wondering how much mortar is needed for a pan this size. For both the mortar bed and the finish layer. I'm looking to buy pre mixed bags. Any feed back would be much appreciated for both quantities and type.:cool:

This should get you there. Figure 10%+ on amount for the slump factor
QUIKRETE® - Quantity Calculator

Hi strength concrete would be good here. Code 1006 Fiber reinforced

http://www.reboysupply.com/quikcrete.pdf

You will need 3 60 lb bags of "sandmix" which is sand and portland cement at a ratio of 3 parts sand to 1 part portland. You will also need 1 bag of mason sand. When you mix the mortar, it's 1 shovel of sand to 4 shovels of sandmix. This will give you the desired 4-1 ratio. You can add a bit more sand than that up to about a 5-1 ratio. You do not want any concrete mixes containing lime for your preslope layer or your setting bed. Lime makes it too sticky to work correctly.

When you mix the mortar, only use enough water to make it a packable mixture, like sand castle sand. It does not get poured, it gets placed and packed. There is no "slump" with mud. If there is slump, you've used way too much water.

Now arriving at the above amounts too the following things into consideration...

Assuming your drain is centered, the distance from your drain to any of the corners is 1.95 feet. That slope of .25" per foot works out to be your thickness at the drain, plus 0.4874" of mud. Rounded off to .5 means the perimeter thickness will be 1.25" if the drain thickness is .75". With your setting bed being uniformly 1.25" thick, that gives an average thickness of 2.25" and that is the equivalent volume of 3.125 bags of sand mix. That will be cut with sand so you will have more than enough, including waste with 3 bags of sand mix and 1 bag of sand. Should your thickness at the drain be only feather edged and around the perimeter being 1/2", then your needs drop, but since the components are very cheap, may as well be certain to have enough on hand.


With a minimum thickness of 3/4" at the drain, over a slab, you can use thinset to bond your preslope layer to the slab. Over a wood subfloor, you use 15 lb roofing felt, diamond lath, and then pack your preslope on top of that.

If your preslope layer is less that 3/4" at the drain, follow the prep steps above, but mix your preslope layer with liquid latex instead of water.

Don't use any lath in the middle if any of the layers, only under the preslope if over wood. With the size of that pan, you do not need wire re enforcement in the middle of any of the layers.

You will need a bag of mortar mix for forming your curb. After the liner is in and passes a 24 hr leak test, fold lath over the curb, nail only to the outside and form the curb using the mortar mix. The lime in the mixture will give it the vertical cling. Your setting bed of mud will pin both the lath to the inside of the curb and the cement board walls against the framing.

Please post back to this thread with any other questions as your project progresses.

Good luck.

The advice given is correct. However, if you are asking this question I am assuming this is your first attempt at a custom be. My question is why. A correct bed requires skill and knowledge, some of us don't even do them. You have so many other options that narrow the chance of a fatal error suck as foam board pan liners and complete fiberglass or acrylic pans. Some of these foam pans can even be tiled so why the mud for a first timer?

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Originally Posted by ;

3.125 bags of sand mix.

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Bljack. With out a doubt here you are a sharp cookie. I was impressed with your post on you knowledge and math. As a tradesmen I got a nice pleasant laugh on the .125 of the sand mix. AS we say in the field " your killing me man" I will get my .125 trowel out to do this. Not making fun of you hear so don't think that. I love when a person knows there stuff. Sometimes I do the same thing in the field and my guys tease me about it " oh here comes the slide rule guy" And don't scare the customer away or overwhelm them.

Keep up the good post!!

I do agree with bal1 being the easier way unless this is an odd size installation

I just found the example I was thinking of. System components - Schluter-Systems

Thank you for your feedback. Bljack amazing man, exactly what I needed. Why because I am extremely confident and capable of doing anything I want. How do we learn how to do things? Reading books and attempting what we've read. Fear of failure leads to no joy of success.

OK I understand the need for a challenge now and then. I f you are dead set on trying this you may find this helpful. How to Build a Shower Pan