Lay a large sheet of tar paper on the entire floor of your shower pan and smooth it out as flat as possible.
How to make a shower floor.
Also make sure your floor is pre sloped before installing the rubber liner in the following steps to prevent.
They re cheap easy to install and immediately add texture to your floor which significantly reduces your chances of slipping.
Pour mud into the shower pan mixing it with a trowel as you go to get rid of air bubbles.
The top of the drain should be 2 inches above floor height and you want to mark the walls and curb to a height 2 3 4 inches above the floor as a guide to the amount of mud you need to maintain a 3 4 inch slope.
Drive a nail into the floor every 8 12 inches 20 30 cm so the tar paper stays in place.
The shower in this project will be flush with the side of the whirlpool bath so the frame needed to extend under the tub overhang.