Shower pan installation involves understanding the basics of construction. Setting the liner on the plywood subfloor, cutting the drain hole, and laying a composite pan are easy enough for most do it yourselfers to accomplish.
Installing Moisture Barrier
Remove the old tub and determine the condition of the plywood flooring. A rubber liner needs to be placed over the plywood to act as a moisture barrier and prevent the wood from rotting. Once you have boxed the area and sealed the subfloor, pour sand.
Installing the Shower Pan
The shower pan is made of a composite material and is typically comprised of a single piece. Place the shower pan composite over the sand and align the drain hole. Use a level to ensure that the shower pan rests properly on the subflooring. Once that has been done, install the cement backer board and prepare the shower for ceramic tile or whatever surface material you choose.