Shower floor trays are the basins that are installed in the floors where showers are placed. With bathtubs, the tray and the bathtub are the same thing, but with shower-only systems, a tray is needed to catch the water and protect the floor. Even showers with tile floors often have some type of tray material that is installed before the tile in order to differentiate the shower from the rest of the bathroom floor. You should try to have your shower tray installed by a professional when possible to avoid any future problems with leaks.
Install It First
The shower tray should be the first thing you install (or have installed) in your bathroom. Not only is it easier to install the tray before working up on the walls, but it is also better for the shower itself. Both tile and moulded walls can be installed over the tray so they are set down firmly on it, thus allowing for a more watertight seal. Installing the tray afterward can lead to leaking problems.
Focus on the Waste Line
The waste line is the pipe that connects to the shower drain and carries all the waste water away. This is one of the most important parts of the shower tray and deserves close attention. Make sure that the waste line is level and connected properly to the tray, with the mechanism to open and close the drain in place. If you want a raised shower tray, you may need to lead the line out through the wall instead of the floor, so explore your options to see what will work best for your particular bathroom set-up.
Level It Out
Make sure the shower tray is level, then check it again and again. Many shower trays are placed on a bed of cement with a little filler sand and mortar. Some use layers of adhesive. Either way, you have a little wiggle room, so get out the level and make absolutely sure all areas of the shower tray are level. Not only will this prevent leaks from forming, it also makes a more solid base for the other shower components.
Sealing is another very important element of installing a shower tray. All edges of the tray where it meets any other type of material should be sealed. Silicone caulk is one of the most common materials used, but check your shower tray's manufacturer recommendations to see what type of seal works the best.