Step 4 · Apply Mortar and Set the Pan
Using a trowel, scoop the mixed mortar onto the roofing felt in the shower alcove. Create several large, flattened mounds of mortar, each about 2 to 3 inches high. Distribute them evenly across the area where the pan's bottom will rest, ensuring the entire base will be supported. Do not create a flat, level bed; the pan will level itself when pressed into the mounds. Carefully lift the shower pan, align the drain assembly over the drain pipe, and slowly lower it into the alcove, pressing it down firmly into the mortar bed. The goal is to squish the mortar, forcing it to conform to the shape of the pan's underside and provide complete support.