Leveling Shower Pan

[Winger27]

I just bought a Onyx shower base. It need shimmed about 1/8 on one corner. My concern is these are made to simply sit in the subfloor, what about the gap after I lift one corner, will it stress and crack. This is a solid/heavy base is there any problem.
Thanks

 

[Reach4]

Check these:
https://terrylove.com/forums/index.php?threads/shower-base-flex-around-drain.79137/#post-575076
https://terrylove.com/forums/index....ed-for-one-piece-maax-fiberglass-shower.59860

 

[Sponsor]

 

[Jadnashua]

Two goals with any shower base:
- needs to be level at the rim
- needs to not rock or deflect

Depending on the strength of the material will depend on whether shims will work versus a larger surface area. Something like cast iron base is stiff enough so that shims work fine if you aren't dealing with a concentrated load of a small foot, but on the other end of the scale, a thin fiberglass/acrylic shell will need much more support to prevent flex. I don't know where yours lands in that range.

What does the manufacturer say about leveling and support?

Is your floor flat and level?

 

[Winger27]

Thanks for the info. My floor is a little out of level thus the shim. The manufacturer says not to make a mortar bed so it can expand with temp changes. It weighs about 200# and has a flat bottom, it's a composite type. From manufacturer:
"Typically laying it on a flat surface (like your subfloor) and putting weight on the high spots will allow the base to settle back flat". Does this make sense?

 

[Jadnashua]

It's possible that the pan will take a set over time to conform to the floor. The goal of a mortar bed is to provide support and to level...you could even put some plastic on top of it so it wouldn't bond. Some underneath as well, which would keep the moisture in so it will cure harder. It depends somewhat on how far out of level the floor is. You want slope from every spot to the drain. I can't say from experience what might work best.

 

[Winger27]

The manufacturers instructions/video have no mortar or anything of that type under it. They say it will form to the floor