A one-piece unit is the simplest shower to install, though you may have a limited choice of colors. Buy a base that’s at least 34 inches wide, checking whether it must be set in thin-set mortar or in a bed of sand or if it can simply be placed on the floor. Before you begin, prep the space by installing a drainpipe with a trap in the center of the base, as well as supply pipes, faucet, and a shower riser. The flange should be level with the floor. Run the supply pipes after the framing is installed. Also, make sure you’re comfortable working with plastic and copper pipe, framing a wall, and installing tile. Follow these step-by-step instructions on how to build a shower enclosure. Editor’s Tip: If the base uses a PVC flange, cement the drain flange to the drainpipe; the flange should be flush with the floor. Set the gaskets on top of the flange. Place the shower base over the drain hole. Check that the gaskets are still in place. Screw the drain body through the hole in the base and into the flange. Attach the strainer. Understanding One-Piece Shower Units Corner and rectangular shower stalls—made of acrylic fiberglass or polystyrene—are much easier to install than a custom-made enclosure. One-piece units are designed for new construction only because they are too large to fit through a door. Three-piece units are quickly assembled and are ideal for remodeling. The walls of these units must be installed against solid walls. A corner unit can simply be installed in any corner that is reasonably square. A rectangular or square unit requires an opening of the correct width and height.
