Things You'll Need
Shower drain extension kit
Re-tiling a shower can be messy, complicated and time-consuming. You can make it easier on yourself when re-tiling your shower if you simply tile over the existing tile. As long as the original tile is still watertight and in relatively good shape, it will make an excellent foundation for another layer of tile. The problem with this approach, however, is now that the tile is raised, the old drain will be at the original level. In this case, you will have to raise your shower drain when re-tiling. Luckily, there are drain extender kits available that will make this process much simpler.
Unscrew the shower drain grate from the top of the drain. Set the screws aside.
Use a strong household cleaner or bleach and rags to clean any mold, mildew or debris off the drain. Allow it to dry.
Measure the side of one of your tiles. Add an extra 1/8 inch to compensate for grout. This is the height by which you need to raise your drain.
Set the rubber tile spacers on top of the drain. Align the screw holes in the spacers with the screw holes in the drain.
Set the plastic ring extension on top of the rubber spacers. Make sure to align the screw holes with the rubber ring and drain opening below.
Place the drain on top of the plastic and rubber extensions, making sure to align the screw holes as above. Insert the screws and tighten.
You can use the rubber extensions from a number of different kits if you need to heighten the drain further.
If the screws are hard to remove, place a few drops of penetrating lubricant on them and allow to soak in for about 15 minutes.
Wear gloves when working with harsh cleaning chemicals.