Preparing the Base

• If you build a shower base, or have someone else do it, you must start out the right way. The tile must be installed on cement board or a bed of mortar. The mortar bed has to be 2½ to 3 inches thick and the slope must be ¼ inch per foot leading to the shower drain.
  
  Place a waterproof liner or membrane on top of the mortar after it is cured. Run the membrane about 8 inches up the studs of the shower wall and cover the shower base curb. This is a rubber-like material that is waterproof and resistant to standard household chemicals. There are two basic types, chlorinated polyethylene (CPE) and polyvinyl choloride (PVC). It is much easier to work with CPE, but CPE is about triple the price of PVC.
  
  Apply a coat of mortar over the membrane. This not only protects the material, but also provides a solid surface for the tile to adhere. Don't forget to cut out the drain.
  
  A pre-cast product will save you a lot of time. The pre-cast shower base is is probably the best choice for most shower base tile installation projects -- especially if you have never built a shower base from scratch. Pre-molded shower pans have the curbs and slopes already structured into the pans. You only need to lay some mortar in the area and set the shower base in the frame.
  
  Account for the thickness of the tile mortar and grout so that the finished tile floor of the base is equal to the height of the drain.
  
  

Installing the Tile

• Stuff a rag in the drain opening to keep it free of debris. If you are replacing tile, use a hammer and cold chisel to remove the old tiles. If you are tiling the shower walls, complete the walls first. Use vertical and horizontals lines to mark the placement of the tiles.
  
  For a uniform appearance, distribute the tiles evenly across the shower base. Avoid the use of narrow shards of tile in the corners. Decide on how you will fit the tiles around the shower base drain.
  
  Use a notched tile to apply the adhesive. Don't cover your reference lines. When setting the tile, apply a bit of pressure and a slight "twisting" motion to set the tile into place. Wipe off any excessive adhesive immediately
  
  Allow the tiles to set for at least 24 hours before you apply the grout. Clean any extra grout off the tile surface. Apply the sealer according to the manufacturer's instructions. Apply a waterproof sealant in the corners and at the joints.