How to reinforce shower pan threshold?

[127bit]

The left rear floor corner is highest (the shower pan touches/sits on the floor), sloping down diagonally to the front right corner (lowest). The front right corner shim is 5/8", the left front corner is 3/8" shimmed, with shorter shims under left middle and right rear corner.
The pan perimeters are level and ready for the mortar to be applied to the underside. However, I don't know how to support the threshold flange, especially as the gap below it is a gradual wedge shape. I think that if the threshold is not properly supported, it would begin to crack as it is periodically stepped upon.

1. Should I form a mortar mini-curb to be vertically flush with the threshold to avoid trapping water on a 'step'.
2. Would forming a mortar mini-curb at that location not gradually wick water under the pan?
3. Might stepping on the threshold not eventually crack the mini-curb?

Advice here will be most appreciated.
Thank-you

 

[bud16415]

Welcome to the forum.



I think I would with that much slope build a dam across the front edge and pour a self-leveling mix in and create a level flat surface to work off of. Then when setting the pan use some stiffer mortar ad a bedding material to support the pan. I have never done this so others could well point out problems doing this. I have seen it done when setting one piece shower tubs to add support below the floor.



The product that comes to mind is called cement-all.

 

[127bit]

Conclusion: I stuck a strip of painting tape along the threshold, flush with its bottom edge. Then I set the bed of mortar including a curb about 1.5 inches deep straddling the threshold bottom. Levelled the pan, waited about 2 hours, then scraped the excess curb away, leaving its face flush with the threshold bottom. After its fully dry I'll pull the tape off and probably press a bit of caulking along it once I've got the floor prepped later. Thanks for the suggestions.