Setting Americast tub in mortar with grid on bottom

[justinae]

Just got the tub and ready to set in a mortar bed. I have one question first. I plan to cover the mortar in plastic, but the bottom of the tub is a grid with cavities about 1" or so deep, lots of them. My concern is that the plastic will prevent the mortar from completely filling the cavities and I'll have a bunch of small air pockets. I don't think it would affect the tub in terms of flexing because they would be so small, but still wonder. I could go without the plastic, but that just flies in the face of conventional wisdom for preparing for when the tub will eventually come out.

thoughts?

[johnjh2o1]

I don't think American Standard recommends setting there tubs in mortar.

John

[hj]

A/S says not to set it in concrete, but even if you did it, the grid is what supports the tub, NOT the air pockets.

[justinae]

I called them and they said no problem it won't void the warranty. The instructions even provide it as an option.

[justinae]

From the manual:

"INSTALLATION - BEDDING MATERIAL (MORTAR, SANDMIX, ETC.) IS ACCEPTABLE. SUB FLOOR MUST BE STRUCTURALLY SOUND & FREE OF MOVEMENT / FLEXING"

This may sound naive, but if there were several small air pockets in the grid, could condensation collect in there or have some other undesirable consequence or am I over thinking it?

[ballvalve]

Overthink.....Dont sweat the air pockets and forget the plastic. It WILL all come out on demo day.

If you still cant sleep, butter the bottom with plaster of paris to fill the voids and in a half hour you can turn it over. Mortar shrinks when it sets, unless you do a very dry mix with almost no slump. That is worth thinking about.