Alternatives to Building a Watertight Shower Base and Floor

Most bathroom remodeling projects entail a stone, ceramic or procelain tile shower complete with bench. While this is not rocket science, homeowners have to be sure that the shower base and floor are water tight and sturdy to avoid costly repairs to areas below and adjacent to the shower.   

Bathroom remodeling usually involves three elements when it comes to showers:

  • Use the bath tub as the shower floor, which is the easiest and least expensive.
  • Install a prefabricated shower pan that does not have to be sloped or tiled- not the most attractive.
  • Construct and install a shower base and floor with tile- generally used in most remodeling projects

For those you who choose the third option, there's a lot to consider, specifically the expertise of your plumber, carpenter and tiler. The shower area will have to be framed and the Durock or Hardiebacker installed on the walls by your carpenter. Off course your plumber will provide the rough plumbing for the drain and water supplies. It is the tiler who will actually install the shower base and floor.

Here are the steps necessary to build a shower base and floor:

  1. Frame the Box
  2. Spread Out the Rubber Membrane
  3. Attach the Membrane
  4. Cut Out the Drain Hole
  5. Attach the Drain Plate
  6. Screw In the Drain
  7. Create the Concrete Mixture
  8. Pour the Concrete
  9. Allow the Concrete to Cure

Installing a rubber membrane on shower base

  • Applying cement over rubber liner and sloping it 

If the job is not watertight, you will have to remove the tile, wood subfloors and joists to repair any water damage. Needless to say, this this will be both extensive and expensive. You'll also have to buy all new tile and pay another tiler as well.

Is this a do it yourself (DIY) Project?
I think that experienced DIY folks can take this on. They just have to make sure that the rough plumbing is installed and following the directions provided in many books and on the Web.

If you are not a DIY kind of person, but worried about the expertise of your tiler and a watertight floor, you should consider using the Schluter Shower Stystem line of products which includes:

  • Prefabricated KERDI shower trays that are properly sloped
  • Prefabricated KERDI shower curbs (aka dams)
  • A KERDI drain that works with the shower tray
  • A KERDI access ramp if you are building a handicap accessible shower (no curbs)
  • Other pieces

Diagram of Schluter Shower System

Size of shower

If you elect to go with the Schluter Shower System you will have to plan well ahead. The prefabricated shower trays come in a variety of sizes and all accept the KERDI Drain and waterproofing membrane (it comes in orange rolls). The shower tray sizes are:

  • 48" x 48" (122 cm x 122 cm)
  • 32" x 60" (81 cm x 152 cm),
  • 72" x 72" (183cm x 183 cm) with centered drain placement,
  • 32" x 60" (81 cm x 152 cm) with drain placement 10" (25.4 cm) o.c. from the end of the tray.

A Picture is Worth a Thousand Words
There are several videos of the Schluter Shower System. The system is designed for both wooden and concrete floors and is relatively flexible. We recommend you watch the videos to gain at least a basic understanding of how the system works.

The Shower Installation Handbooks contain great information that with extensive illustrations if you are thinking of doing this yourself or want to share it with your tiler or contractor. (English) (French) (Spanish)

Other Resources
As I was putting this post together I received an email from BathExpress located in the Washington DC area. They are using the Schluter Shower System to convert a bath tub to a walk-in shower. Call them at 703-978-BATH (2284) in Northern Virginia or 202-362-BATH (2284) in Washington D.C. or Maryland for an estimate and ask about their $250 discount coupon.