Building a waterproof shower pan is the most important part of a bathroom remodel. Here is the best method in assuring an everlasting waterproof membrane in the floor of your shower. DAY 1 1) Felt paper is attached to the sub-floor with roofing nails. 2) Expanded metal lathe attached with roofing nails. 3) Pre-slope. This is accomplished by using a Portland Cement and Sand mix and making sure all water will flow into the drain. It is important that there are no dips or depressions and the slope is constant to the drain. 4) Along with the pre-slope it is important to build the first half of the curb also using Portland Cement/Sand mix. DAY 2 5) Install the pan liner in a thin bed of thinset over the pre-slope and attach it to the drain using PVC glue. Allow the PVC glue to cure, then fill the pan with water to assure no leaks and call the local inspector. All permitted jobs must have the local inspectors approval, they must see the pan full of water with no leaks or bubbles. DAY 3 6) Top coat. This is the final step in the preparation stages of the shower pan. The final layer of Portland Cement/Sand Topping must be very smooth and like the pre-slope shed all water into the drain. This layer determines the final finish elevation of the tile. 7) With the final top coat build the second half of the curb. All rough prep work is done. Allow to cure overnight or as long as it needs for your local climate. It may take a couple of days. DAY 4 8) Redguard the pan and curb and at least a foot up the walls. Redguard is a brush on waterproof membrane that creates the first of many waterproof barriers in your shower. Once the Redguard has cured, tile is ready to install.