New whirlpool tub: Part 1: Mortar support?

Hi Folks-
This is the first of two posts concerning the installation of a new whirpool tub, an American Standard Williamsburg Elite 5' with integra apron. I'm splitting up the posts because they are on different subject areas.
This is my first tub installation. Demolition and removal of the old one (a plain steel tub) took much of the weekend. Quite a learning experience.
Anyway, here's my first question: How exactly do I set up the mortar bedding?
The installation instructions for the new tub say:
"This bath is not self-supporting and must be supported along it's [sic] entire bottom. Support with mortar or grout. ... We recoommedn the use of mortar as bedding material (sand is not recommended. Apply enough bedding to support the complete bottom of the bath. After the bedding has been poured, and before it sets, position whirlpool or bath within recess... allow the bedding material to completely harden before applying weight to the rim or bottom of the bath."
There is a diagram, that just shows an amorphous area representing the bedding.
What do I do, just mix up a bunch of mortar and slop it onto the rough floor? The instructions give no indication about how much is needed, or how to contain it in the area needed, or even the dimensions showing exactly where the mortar needs to be.
Should I put a plastic sheet down directly on the rough floor to make it easier for the next guy to pull this tub some years from now, rather than having to rip the tub out of the mortar?
I'm a little freaked out by this mortar thing. Any advice would be much appreciated.
Thanks
Marc
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1. Doesn't American Standard have a support line?? They should tell you how thick a bed is required. I'd figure and inch or so.
2. Yes, just slop the mortar down on the subfloor. If it "runs", you've mixed it to thin.
3. Forget the plastic. It kinda defeats the purpose which is to BOND the tub to the floor so it won't move and so that your weight, plus the water weight won't crack the bottom of the tub (fiberglass)
4. Measure bottom area of tub and sketch roughly onto plywood; add an inch all around and make the mortar bed.
5. Have a friend to help you get the tub in place and aligned with the plumbing before that mortar starts to set.
6. Vow never to buy something you haven't read the installation instructions for in advance. <g>

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says...

Thanks for both posts. I'm definitely getting another set of hands to help with this one; my neighbor is a handyman kind of guy and has installed these tubs before. In fact I bought this one on his recommendation, so he'll help.
As to the reading of instructions before buying, I'll admit some guilt here. I demo'ed the old tub / surround before buying anything specifically because I wanted to see what I was getting into before plunking my money down.
Got the old tile-on-rotten-drywall (yuk!!) out and found a reasonably nice level-square-plumb area, abeit a 30" site rather than the 32" I'm needing. Getting the tub out was much harder than planned. I thought it was iron, but it was steel, so that first whack with the sledge to shatter it didn't go according to plan...
Anyway, having a nice clean 32" opening, and being prepared to drop my dedicated circuit line in, I wasn't expecting a few of the things in the manual. You are right; I should have downloaded the instructions before buying.
Thanks again for your help. With the aid you and others have given me, and with some hands-on help from my neighbor, I think I'll be OK!
But, you'll probably see a few more posts before I'm done.
:-)
Marc
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I've installed that very tub. The reason they do not give the thickness is it depends how far your deck is from the sub floor, height of finish material, etc.
Anyway - if you set it in dry you can measure the gap between the subfloor and bottom of the tub. add 1/2 inch of mortar for squeeze out. Use mortar not concrete. I had to build a dam to contain the mortar where I wanted it before it set up. I just used some cardboard folded into an L shape stapled to the subfloor.
for everyone else - The reason this tub requires this is that its acrylic. A pretty thin acrylic at that. Its very flexible. By using the grout or mortar it feels more like a cast iron tub when your in it. It wont flex and feels sold. I would recommend this technique on all acrylic and fiberglass tubs and shower bases even if its not called for in the manufactures instructions.

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Brian-
Thanks for the information. I like the cardboard L shape idea!
Marc
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