KERDI-FIX is Schluter's flexible sealing and bonding compound — the product you reach for when you need to waterproof a penetration, bond the KERDI membrane to a surface that won't take mortar, or seal a gap that standard thin-set can't handle. It's a single-component elastomeric compound based on silane-modified polymer, which means it stays flexible after curing, bonds well to almost everything, and doesn't off-gas solvents.

In practical terms: use KERDI-FIX wherever KERDI membrane meets a surface that isn't suitable for thin-set bonding — metal drain bodies, glass, existing painted surfaces, pipe penetrations, and transitions between the KERDI system and other materials.

Where it gets used

• Bonding KERDI membrane to stainless steel KERDI-DRAIN flanges (stainless flanges don't bond well to mortar — KERDI-FIX is the specified method)
• Sealing pipe penetrations through KERDI (when KERDI-SEAL prefab seals aren't the right fit)
• Bonding KERDI to non-porous substrates (glass, metals, some plastics)
• Sealing gaps and transitions in the waterproof assembly
• KERDI-BOARD corner and edge sealing in applications that need flexibility

Key properties

• Single-component — no mixing required
• Elastomeric (stays flexible after cure — handles movement without cracking)
• Odor-neutral, solvent-free
• UV- and weather-resistant (interior applications primarily, but durable)
• Bonds to wood, stone, concrete, metal, glass, and most plastics
• Works in wet areas — compatible with full immersion applications

Pro Tip

When sealing around a stainless steel KERDI-DRAIN drain body, apply KERDI-FIX to the bonding flange, press the KERDI membrane fleece into it firmly, and let it cure 24 hours before any further waterproofing steps. Don't try to rush this joint — it's the single most vulnerable point in a tiled shower and the one that fails first on cheap installations. Get it right and you'll never think about it again.

Pairs with

• KERDI waterproofing membrane
• KERDI-DRAIN bodies (especially stainless steel — where mortar bonding isn't ideal)
• KERDI-BOARD panels
• Any Schluter shower system component requiring a flexible waterproof bond