A shower pan is the waterproof foundation that directs water to the drain and protects the subfloor from leaks. A properly built shower pan ensures durability, moisture protection, and proper drainage. Whether you are creating a custom tiled shower or replacing an old base, building a shower pan correctly is essential for long-term performance. High-quality shower systems—like those paired with Moon Shower fixtures—benefit greatly from a strong, well-constructed foundation underneath.
Shower drain assembly
Waterproof liner (PVC or CPE)
Mortar mix (deck mud)
Plastic or metal lath
Silicone sealant
Waterproof membrane (optional for extra protection)
Trowel
Utility knife
Measuring tape
Level
Bucket and mixing tools
Staple gun
Mortar float
Having these items ready ensures a smooth construction process.
Start with a clean, level, and solid subfloor.
Soft spots
Moisture damage
Uneven surfaces
Repair issues before continuing to ensure a stable base.
The drain assembly usually has two parts: a lower flange and an upper flange.
Position the lower flange at the drain opening
Secure it to the subfloor
Ensure the drain pipe is properly aligned
A well-positioned drain is essential for correct slope and waterproofing.
The pre-slope is a thin layer of mortar beneath the liner that directs water toward the drain.
Mix deck mud to a damp sand-like consistency
Spread it across the floor
Maintain a slope of 1/4 inch per foot toward the drain
Let the pre-slope dry before moving on.
The liner protects the subfloor from water penetration.
Lay the liner across the pre-slope
Extend it at least 6 inches up the walls
Avoid puncturing the liner below the wall height
Cut a hole for the drain opening
Secure only along the upper edges
Proper liner installation is critical for leak prevention.
Apply silicone where the liner meets the drain opening.
Place the upper flange over the liner
Tighten bolts evenly
Ensure the weep holes remain open
Blocked weep holes cause standing water and mold beneath the tile.
For wooden subfloors, place metal or plastic lath on top of the liner to reinforce the final mortar bed.
This layer forms the tile-ready surface.
Mix mortar (deck mud)
Spread over the liner, maintaining the 1/4 inch per foot slope
Pack it firmly with a trowel
Smooth the top surface
Allow it to cure completely.
For added protection, apply a secondary waterproof membrane on top of the cured mortar bed.
Prevents moisture absorption
Extends the lifespan of the shower pan
Provides a better bonding surface for tiles
Ensure full coverage around corners and seams.
Once the mortar bed is dry:
Slope is consistent
Surface is smooth
No cracks or soft spots
The shower pan is now ready for tiling or finishing.
Without proper slope, water will pool instead of draining.
Fasteners below 6 inches can cause catastrophic leaks.
Essential for allowing moisture beneath the tile to escape.
Deck mud—not concrete—is required for stability and drainage.
Flat liners trap water and promote mold growth.
A properly constructed shower pan:
Directs water efficiently to the drain
Prevents leaks into the subfloor
Supports tile installation
Maintains structural integrity over time
Works seamlessly with high-quality shower fixtures
This foundation enhances the overall performance of coordinating components, including those from Moon Shower.
Hair and debris can slow drainage.
Repair cracks to prevent water intrusion.
Soft floors, musty smells, or discoloration indicate water damage.
Preserve sealants and waterproofing.
Reduces moisture buildup and mold risk.
Moon Shower designs fixtures that perform optimally when supported by a well-built pan.
Stable pressure control that prevents water overflow
Durable materials that resist moisture damage
Smooth installation compatibility with modern shower structures
Long-lasting cartridges and valves that reduce maintenance stress
Aesthetic consistency with premium shower builds
A strong foundation combined with quality fixtures ensures a high-performing shower system.
Previous:
