Roll out the molding around the perimeter of the shower to determine how much you will need and where cuts will need to be made to accommodate the corners. Cut the strip of molding to size by laying it on a flat surface and making several shallow cuts with a utility knife until it is cut through.
A vinyl cove base molding is a great way to create a waterproof transition between the shower base and walls. The molding is available in long rolls that can easily conform to the walls of the shower. The roll can be heated, bent and cut to allow it to move around the inside corners of the shower without multiple seams that could potentially allow water to seep into the shower base. The cove base should be installed after the shower base and before or at the same time as any wall coverings are installed.
Locate the areas on the strip of the molding where the corners will be. Score the molding with a utility knife lightly where it will bend into the corners. At the base, where the cove curves, make a small triangular cut with the wide portion of the triangle at the bottom of the cove and the tip intersecting with the scored mark.
Spread adhesive onto the wall where the base will be installed using a trowel. Press the cove into the adhesive firmly, smoothing it along the wall with your hand.
Heat the vinyl with a heat gun when you approach the corner to soften it. Bend it inward along the score mark so the two sides of the triangle come together and press the cove into the corner.
Roll the cove base into the wall by applying pressure with the hand roller. Make several passes with the roller around the entire perimeter of the shower to help adhere the cove securely to the wall. Allow the adhesive to dry for 24 to 48 hours.