These instructions apply to all CASTICO alcove shower pan bases (left/right drain, center back drain, and center drain models). For corner bases, see Corner Shower Pan Base Installation Guide.
Read the full guide before starting. These instructions are not all-inclusive, and images in the printed guide are for illustration only. We strongly recommend a professional installer if you have any doubts about the process.
Available models
All dimensions include the thickness of the waterproofing flange. Drain center positions are measured from the drain-end wall (along the length) and across the width.
| Drain type | Size | Drain center |
|---|---|---|
| Left or right drain (universal) | 60" x 32" | 8 1/4" from end wall, 16 1/16" across width |
| Left or right drain (universal) | 60" x 36" | 8 1/4" from end wall, 18 1/16" across width |
| Left or right drain (universal) | 72" x 36" | 8 1/4" from end wall, 18 1/16" across width |
| Center back drain | 48" x 42" | 24" along length, 8 1/4" from back wall |
| Center back drain | 60" x 42" | 30" along length, 8 1/4" from back wall |
| Center back drain | 72" x 42" | 36" along length, 8 1/4" from back wall |
| Center drain | 36" x 36" | 18 1/16" x 18" |
| Center drain | 48" x 34" | 24" along length, 17 1/16" across width |
| Center drain | 60" x 32" | 30" along length, 16 1/16" across width |
| Center drain | 60" x 36" | 30" along length, 18 1/16" across width |
Flange orientation
- Option 1, standard alcove: the flange kit for this orientation is included with the base.
- Option 2, narrow entry: not standard. The Narrow Entry Flange Kit is sold separately and comes with its own installation guide.
Before installation
- Review the complete guide before attempting to install.
- Inspect the product and package contents. Do not begin installation if any component is damaged, has a manufacturing issue, or is missing.
- Confirm the base will fit the intended location, including the drain location.
- Observe local building and plumbing codes.
- Prepare, level, and waterproof the shower area.
- Indoor use only. Do not install in direct sunlight.
- Do not discard the box lid. It is used to protect the base during wall installation.
Package contents
- Shower pan base (A)
- 5" x 10" drain cover
- Waterproofing flange kit: left flange (C1), right flange (C2), back flange (C3), and 13 screws (C4)
All bases are compatible with select standard 2" drains for pre-formed bases. See Recommended Installation Products & Accessories for approved drains.
Required for installation (not included)
2" shower drain, safety goggles, measuring tape, utility knife, leveling tools, putty knife, notch trowel, rubber mallet, bath silicone sealant, drill, tile saw, and construction adhesive (polyurethane) or polymer-modified thinset mortar.
Warning: Standard (unmodified) thinset mortar is not suitable for this product. Use only adhesives approved for non-porous stone surfaces, such as polyurethane construction adhesive or polymer-modified thinset. Follow the adhesive manufacturer's instructions for substrate prep, application, coverage, open time, working time, and curing. Failure to do so can cause poor bond strength or loss of adhesion, and may void the warranty.
Step 1: Subfloor preparation
The subfloor must be structurally sound, level, and fully supported. Floor joists must be properly sized and reinforced to prevent movement or deflection that may crack the shower base.
- Install cement backer board as needed.
- Use leveling concrete to level the floor if required, then check level.
- Verify the drain location. Rough-in dimensions are measured after backer board and wall preparation materials are installed, and include the thickness of the waterproofing flange.
- Make sure the base drain and the floor drain location align.
Step 2: Shower space and drain preparation
Install waterproof backer boards and complete all required waterproofing before installing the base.
For this step, install only the drain body (AA5), paper gasket (AA4), and rubber gasket (AA3). The drain barrel (AA2) and drain cover (AA1) are installed after the base is in place.
Important: Leave a maximum 7" x 7" clear opening around the drain body. Fill the rest of the area with mortar, shims, blocking, or other support so the base is continuously supported. Large unsupported voids create stress points that can crack the base.
Step 3: Base preparation
- Measure the shower area, confirming length and width on each side.
- If the base needs trimming, account for the flange dimensions before cutting.
- Bases may be trimmed up to a maximum of 1 1/2" per side.
- Do not trim exposed edges. Trimmed edges must be installed against a wall.
- Use painter's tape over the cut line and tile cutting tools. Safety equipment is strongly recommended.
Step 4: Flange preparation
- C1 and C2: cut only from the straight edges. Do not cut the notched edges. Score and snap with a utility knife.
- C1 and C2 must be 3/16" longer than the width of the base.
- C3 must be 3/8" longer than the length of the base.
- Narrow entry layouts: follow the guide included with the Narrow Entry Flange Kit.
Step 5: Flange installation
- Dry-fit the flanges by joining the notched edges to form 90-degree corners and confirm fit around the base perimeter.
- Place all C4 screws 1/2" from the top ledge.
- Install the first screws 2" from each side edge, then distribute the rest evenly.
- Use 5 screws on C3 and 4 screws each on C1 and C2.
Step 6: Set the base
Adhere the base to a level subfloor with construction adhesive (polyurethane) or polymer-modified thinset.
- Construction adhesive: apply continuous 3/4" diameter beads in straight lines, 4" apart. The first and last beads must be 1" from the panel edges.
- Thinset: apply and level with a trowel to the thickness specified by the manufacturer. Back-butter the base with thinset for proper adhesion to the substrate.
- After setting the base, use a rubber mallet to adjust level as needed. Measure level on the flat edges.
- Clean excess adhesive with a damp sponge before it dries.
Step 7: Drain connection
Begin the drain connection before the adhesive dries. Apply silicone to the drain barrel (AA2) and install it per the drain manufacturer's instructions, with the top flush against the base drain area. Clean off excess silicone.
Step 8: Seal the flange seams (critical)
Apply a waterproof silicone bead to:
- The entire edge between the flanges and the waterproof cement wallboards
- The seam between the flanges and the base
- Each corner seam between flange joints
For a cleaner application, apply painter's tape to the base 1/8" from the flange seam to catch excess silicone.
Important: Do not nail the waterproofing flange to the cement boards.
Step 9: Cure and protect
Once the adhesive and silicone have cured, you can continue with the rest of the shower renovation. Curing times vary by product. Follow the manufacturer's specifications.
Cover the base with the box lid before installing wall panels or tile.
Care and maintenance
Clean with neutral soap, a foaming shower and tile cleaner, or a calcium, lime and rust remover, using a cotton knit rag or plastic fiber scrub brush. A water-based impregnator sealer is recommended for long-term care. Do not use solvents, abrasive products, direct household bleach, or scouring tools.
Support
Before returning or uninstalling the product, contact CASTICO Customer Care at (844) 364-2502 or contact@castico-tx.com, 8 AM to 5 PM CST, Monday to Friday. Installation videos are available at castico-tx.com/support.