Preparation

• A roll-in shower has minimum inside dimensions of 60 by 30 inches, which is the typical measurement for a tub. A transfer shower has a minimum interior dimension of 36 by 36 inches. An area of 54 by 54 inches is required to maneuver a wheelchair in a shower. A 60-by-60-inch space is even better.
  
  You'll need to determine the dimensions for your handicap tile shower. Use 2 by 4's to frame the shower walls. After you get the walls framed, you can install the base for your tile. The American Disabilities Act (ADA) guidelines states that showers must be "curbless" or not exceed a 1/2-inch beveled curve.
  
  The subfloor in the shower area must be 1 1/2 to 2 inches lower than the subfloor in the rest of the bathroom. If the subfloors are the same level, you'll have to lower the floor in the shower. Use a system of joists hangers and install narrow smaller-width joists. If your home is on a slab foundation, you will still have to drop the area.
  
  

Install the Tile Base

• There are ADA-compliant shower pans on the market that can serve as a base for tile installation. The drain and splash walls are all incorporated into a one-piece system. You can build your own mortar base for tile. Place a rubber membrane on the surface of the subfloor. Extend the membrane about 8 inches up the studs in the walls and fasten the membrane with a flat-head nail.
  
  The waterproof membrane routes water to the weep holes in the shower drain. The thickness of the concrete can be anywhere from 1 1/2 to 2 inches thick with a slope of 1/8 inch for each foot in order to drain properly. The remainder of the bath floor should slope slightly toward the shower. This way any water will flow back toward the drain.
  
  

Other Considerations

• Attach cement board to the 2 by 4 studs. The cement board, or "Durarock," will provide the surface for tile installation. Install the tile on the walls first and finish with the floor last. You will also need to install an anti-scald shower value that is easily operable by a person with physical challenges. A hand-held shower device must be integrated with the main shower head. Follow the ADA guideline for the final installation of grab bars and shower benches.