How to Make a Shower Pan (Step-by-Step Guide)

A properly installed shower pan is essential for preventing water leaks, mold growth, and structural damage. Whether you are a professional contractor or a skilled DIY homeowner, knowing how to build a shower pan correctly ensures a long-lasting, code-compliant shower system.

This guide explains how to make a traditional mortar shower pan using industry-approved methods.

What Is a Shower Pan?

A shower pan (also called a shower base) is the waterproof foundation of a tiled shower. It directs water toward the drain while protecting the subfloor from moisture intrusion.

Tools and Materials for Building a Shower Pan

Before starting, gather the following materials:

• Shower drain assembly (PVC or ABS)
• PVC or CPE shower pan liner
• Deck mud (sand and Portland cement)
• Roofing felt or plastic vapor barrier
• Metal lath
• Silicone sealant
• Level
• Trowels (flat and margin)
• Utility knife
• Measuring tape
• Stapler or roofing nails

Step 1: Prepare the Shower Subfloor

Proper subfloor preparation is critical to a successful shower pan installation.

• Ensure the subfloor is:
  • Structurally sound
  • Clean and dry
  • Free of flex or movement
• Install solid blocking between wall studs around the perimeter
• Secure the bottom flange of the shower drain to the subfloor

Step 2: Create the Shower Pan Pre-Slope

A pre-slope allows water beneath the tile to drain properly.

• Install roofing felt or plastic sheeting over the subfloor
• Staple metal lath over the barrier
• Mix deck mud to a damp, sand-like consistency
• Form a slope of ¼ inch per foot toward the drain
• Smooth and level the surface
• Allow the pre-slope to cure for 24 hours

Step 3: Install the Shower Pan Liner

The liner is the primary waterproofing layer of the shower pan.

• Lay the PVC or CPE liner over the cured pre-slope
• Extend the liner:
  • At least 3 inches up the walls
  • Completely over the curb
• Cut only small holes for the drain bolts
• Clamp the liner into the drain assembly
• Fold corners—do not cut them
• Secure the liner to studs above curb height only

Step 4: Perform a Shower Pan Flood Test

Flood testing ensures the shower pan is completely watertight.

• Plug the drain with a test plug
• Fill the pan with water just below the curb
• Let the water sit for 24 hours
• Check for leaks or water level drop

Step 5: Install the Final Shower Pan Mortar Bed

• Adjust the drain strainer to finished height
• Apply final deck mud over the liner
• Maintain a consistent ¼ inch per foot slope
• Smooth and compact the surface
• Allow to cure for 24–48 hours

Step 6: Prepare the Shower Pan for Tile Installation

• Install cement backer board on walls
  • Leave a small gap above the pan
  • Do not fasten below curb height
• Tape and thinset all seams
• Shower pan is now ready for tile and wall waterproofing

Common Shower Pan Installation Mistakes

Avoid these common errors when building a shower pan:

• Skipping the pre-slope
• Puncturing the liner near the curb or floor
• Incorrect drain installation
• Insufficient slope toward the drain
• Failing to perform a flood test

Why Proper Shower Pan Installation Matters

A correctly built shower pan prevents:

• Water leaks
• Mold and mildew
• Subfloor rot
• Costly bathroom repairs

Taking the time to install your shower pan correctly protects your investment and ensures long-term performance.

Need Professional Shower Pan Installation?

If you’re unsure how to build a shower pan or want guaranteed results, contact a licensed bathroom remodeling professional for expert installation.

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