The shower in your basement is only as leakproof as the liner you install. Shower pans come in a variety of different types, including fibreglass, vinyl and acrylic. Some of the prefabricated shower pans are seamless and leakproof and do not require liners, but a shower pan constructed from scratch must have a waterproof liner, preferably a vinyl membrane, to keep moisture in.
Vacuum all debris from the basement concrete to prepare the section for your new shower pan liner.
Purchase a 5-feet by 6-feet rubberised asphalt laminate membrane with a reinforcement fabric. You can purchase a shower pan liner at any home store.
Lay the shower pan liner across the concrete floor up each side wall 6 inches. Center the liner and cut a hole out for the drain with a utility knife. (Remove the liner and prepare the drain assembly.) Place a piece of tape over the drain hole to prevent debris from entering in.
Replace the liner with the fabric side down. Center the hole over the drain. Press the liner membrane into the corners and up the side walls. Make sure the shower pan liner lies flat on the shower floor.
Hammer large-head roofing nails through the liner and into the wall studs. Overlap the corners of the liner--making sure they lie flat--and nail them into place. (Fold the corners over like you would if you were making a bed, tucking in the sheets.)
Attach a 2 by 6 board to the front of the shower curb to create a threshold. Nail the board to the studs on each side with 16-penny nails. Wrap the membrane liner over the curb and nail it to the board. (Cut the board to size using a circular saw.)
There are quite a few different types of shower pan liners you can choose from. A popular type is a waterproof vinyl membrane.
Do not tear or rip your shower pan liner to avoid unnecessary leaking.