Step-by-Step Shower Waterproofing Installation Guide

Demolition & Prep

Remove existing tile, drywall, or tub surround down to the studs and subfloor. Inspect framing for rot or damage and replace any compromised lumber. Ensure the subfloor is structurally sound — 3/4 in plywood minimum for tile installations.

• Remove all old tile, mortar, and adhesive residue
• Check studs for plumb and fix as needed
• Repair or sister any damaged floor joists
• Verify drain rough-in location matches your tray layout

Subfloor & Framing

Frame the shower walls with moisture-resistant materials. Install cement board or fiber-cement backer board on all shower walls. For the floor, install your shower tray on a clean, level subfloor.

• Frame the shower curb with 2x4 lumber (if using a curbed tray)
• Install cement backer board on walls with corrosion-resistant screws
• Tape and thin-set all backer board seams
• Dry-fit the shower tray to confirm drain alignment

Drain Installation

Install the drain assembly before setting the tray permanently. Whether you are using a linear drain or square drain, proper height adjustment is critical for a flush tile finish.

• Connect drain body to the waste pipe (2 in no-hub connection)
• Set drain flange height to match tray surface plus tile thickness
• Apply plumber putty or silicone to the drain flange seal
• Test-fit with tray to confirm alignment and height

Waterproofing Membrane Application

Apply the Trugard waterproofing membrane over the entire shower tray and up the walls to at least 6 inches above the showerhead height. This continuous membrane envelope is what keeps water out of your framing.

• Apply a thin coat of unmodified thin-set mortar to the tray surface
• Roll out the membrane and press firmly into the thin-set, eliminating air bubbles
• Overlap wall membrane sheets by at least 2 inches
• Wrap membrane over the shower curb top and down both sides
• Use TruSeal sealant at the drain flange connection

Sealing Joints & Corners

Every inside corner, outside corner, and pipe penetration needs extra reinforcement with Trugard sealing bands and corner pieces.

• Embed inside corner strips in thin-set at all wall-to-wall joints
• Apply outside corner pieces to the curb edges
• Seal around the valve body and any pipe penetrations
• Apply a second coat of sealant over all membrane overlaps
• Allow 24 hours of cure time before flood-testing

Tiling

Once the membrane has cured and you have confirmed a successful flood test, you are ready to tile.

• Use unmodified thin-set mortar over the membrane (modified thin-set can prevent proper bonding)
• Start with the shower floor, working from the drain outward
• Tile the walls bottom to top, using spacers for consistent grout lines
• Install the tileable niche and corner shelves during wall tiling
• Grout all joints, then apply silicone caulk at all inside corners and changes of plane

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