Gather materials: shower drain, pre-slope mortar, pan liner, corner dams, clamping ring, final deck mud, waterproof sealant, backer board, fasteners, and tools
Remove the old shower base down to the subfloor or slab
Inspect and repair the subfloor or slab so it is clean, solid, and level
Install the shower drain at the correct height and location
Mark the shower perimeter and determine the finished pan height
Build a pre-slope layer of mortar from the perimeter to the drain with proper pitch
Let the pre-slope cure
Lay the waterproof pan liner over the pre-slope and up the walls
Cut and fold the liner at corners without puncturing below the top edge
Attach the liner to the walls only above the finished curb height
Seal all seams, corners, and drain connections as required
Install the clamping drain’s lower and upper parts with the liner sandwiched between
Perform a flood test to check for leaks
Install the curb and wrap it with lath and mortar if needed
Place pea gravel or drain protection around the drain weep holes
Add the final deck mud layer over the liner with slope toward the drain
Pack and screed the mud to a smooth, even surface
Let the shower pan cure fully
Install wall backer board above the pan without trapping moisture in the liner
Apply tile or the chosen shower finish over the cured pan
Seal grout and joints as needed after installation