TrueDEK Classic Shower Base – 47 ¼” x 47 ¼”, SKU: 21018

Regular Price $853.00

111 853
SKU: 21018 Category:
Description: 47¼" × 47¼"


  • the easiest, fastest way to build a curbless, level-entry shower is with an ARC shower base
  • installing this shower base and waterproofing your shower can be completed in one day
  • with a TrueDEK shower base you avoid all the difficulty and risk of notching, lowering, or altering the joists
  • ARC TrueDEK shower bases take away all of the guesswork and make building a shower so much easier
  • this shower base is 7/8” thick at the edges
  • cover this base with tile or stone (from ¼” to 1″ thick); this base can also be covered with commercial, weldable vinyl flooring
  • to build larger showers use ARC pitch extensions or appropriate mortar products, or install TrueDEK shower bases side-by-side
  • install TrueDEK bases on any type of joists, on subfloor, or on concrete
  • to complete your shower installation you will need an ARC waterproofing kit and a drain assembly for tile (choose a drain for vinyl only if you install commercial, weldable vinyl flooring)
  • tile that is 2″ x 2″ or smaller conform to the pitched contours of this shower base; for tile larger than 2″ x 2″, make valley cuts so that the tile lays properly on all pre-pitched surfaces
  • when installed properly on joists, all TrueDEK Classic bases will support 800 lbs. or more
  • this product is covered by the manufacturer’s limited lifetime warranty
  • for more details, please see this product’s Specification Sheet
  • please watch our installation videos and understand the TrueDEK Classic Installation Instructions before you begin your project

Specification Sheets

21018 Specification Sheet

What you will need

  • TrueDEK Classic foundation
  • TrueDEK Classic Drain
  • Waterproofing Kit (extra waterproofing supplies may be required depending on the size and complexity of a project)
  • Circular saw
  • Flush-cutting saw or reciprocating saw
  • Power drill
  • Belt sander or orbital sander
  • Hammer Pry bar
  • Level Caulking gun
  • Speed square
  • Measuring tape
  • Scissors or utility knife
  • 3″ or 4″ paint brush (throw-away type)
  • Paint roller and cover
  • Polyurethane construction adhesive (five 10 oz. tubes)—make sure adhesive bonds to plastic and wood
  • Acrylic paintable caulk (one 10 oz. tube)
  • #9 x 2″ ceramic-coated or stainless steel screws
  • 2× lumber for blocking

Video Tutorials

TrueDEK Classic Installation


I lost the screws for my drain for tile. What sizes do I need?

All the screws that come with the drain for tile are stainless steel, and they are metric sizes and thread counts. These are available at many well-stocked hardware stores in their specialty fastener section (often you'll find an aisle with pull-out drawers, and inside the drawers are all kinds of unique fasteners). Here is the screw information:

1. For the four screws that fasten the adaptor to the foundation, you really can use flat head screws that fit, and they don't have to be metric. We recommend #6 or #8 x 3/4" long, flathead, wood threaded style screws in stainless steel or ceramic coated. Always drill pilot holes before driving these screws.

2. To secure the clamping ring, you'll need M4 x 0.7 x 16mm long stainless steel screws. These have to be metric and the proper size and threading to fit the threaded holes in the adaptor.

Why are there more threaded holes inside the drain adaptor?

The drain adaptor is a component in both drain for tile assemblies and the drain for vinyl assembly. The drain for tile model requires only two threaded holes for securing the clamping ring to the adaptor. The clamping ring for a vinyl drain requires four threaded holes, and the holes are larger to accept screws that are bigger in diameter.

Why the difference in screw sizes? The clamping ring in a drain for tile only has to secure the edge of a thin, flexible drain gasket; the clamping ring for a drain for vinyl has to bite down on thick commercial-grade, vinyl safety flooring. The bigger screws provide a stronger grip on the thicker material.

Can you make a custom drain grate for me?

Sorry, we can't, but there are usually local metal fabricators who can do a great job if you give them a design or tell them what you want. You can also try this online source:

Will grates from other manufacturers fit ARC drains?

Fitting grates across manufacturers is tricky because there is no common standard. Out grates are made to metric dimensions that equate to 3/16" thick x 4-7/16" wide x 4-7/16" long.

What holds the linear drain cover in the tile adaptor?

It's a snug fit. There are round rubber bumpers that you insert into pre-bored holes in the side walls of the cover. Pressing the cover into the adaptor squeezes the bumpers just a bit, making for a snug fit. The cover will come out only if you want it to.

How deep is the linear drain cover?

All covers are 1/2" deep.

Why can’t I cut a TrueDEK linear base?

These bases have a mild steel frame that is part of their internal structure. Each steel tube that makes up the frame is set back from an edge of the base by about 1". Cutting through these tubes weakens the structure and may reduce the load capacity of the base, depending on how the base is supported underneath.

Do I need a Premium Kit or a Pro Kit?

The difference between these kits is in the amount of waterproofing supplies that are included.

The Premium Kit has enough waterproofing materials to do a full alcove shower, including the shower base and three walls. The Pro Kit was created for installers who prefer to waterproof the shower base with Tank/10, then use other waterproofing products on the walls.

It's up to an installer to consider compatibility of different waterproofing products and their appropriate use in a shower system.

What color is Tank/10?

The dark gray color of Tank/10 makes it easier to spread over shower foundations and tile backer (you can easily see spots you miss) and the color darkens as the compound dries. When applying the second coat it's easy to see the areas that are wet (lighter gray) and dry (darker gray).

What is the shelf life of Tank/10?

Tank/10 has a 3 year shelf life. A born-on date is printed on a label that is adhered to every bucket, and that date is also written on a label that is stuck to every waterproofing kit box. This shelf life applies to unopened containers. As soon as a container is unsealed the aging process will accelerate, just as with paint or glue or any other liquid.

Enter your zip code below to find ARC dealers near you: