The weakest point in any shower waterproofing is wherever a pipe comes through the wall. Cutting a hole in your KERDI, wrapping it tight, and hoping it holds isn't a real plan — water finds those gaps, and by the time you see damage it's behind the tile.

KERDI-SEAL pipe seals are pre-fabricated rubber gasket seals designed specifically for pipe and valve penetrations through KERDI, DITRA, and DITRA-XL assemblies. The over-molded rubber gasket creates a compression seal around the pipe body, while the KERDI fleece bonding flange embeds into thin-set mortar just like the rest of your membrane — watertight, warrantied, and done.

Two seal types — know which you need

• KERDI-SEAL-PS (Pipe Seal) — for round pipe protrusions: showerhead supply, body spray ports, hand shower inlets. Available in multiple diameters — match to your pipe OD.
• KERDI-SEAL-MV (Mixing Valve Seal, 4-1/2") — for the shower mixing valve rough-in body. Designed to seal around the valve where it protrudes through the wall membrane. Fits most standard thermostatic and pressure-balance valve rough-in bodies.

How it installs

1. Apply thin-set to the fleece bonding flange.
2. Slide the rubber gasket over the pipe/valve — it should fit with light resistance, not slide loosely.
3. Press the seal into the KERDI assembly, overlapping the membrane by at least 2".
4. Install the main KERDI membrane over the seal with another 2" overlap onto the seal's flange.
5. The rubber gasket compresses around the pipe as the system sets.

Pro Tip

Dry-fit the seal before applying any mortar. The pipe should pass through the rubber gasket with firm resistance — if it slides through easily, you have the wrong diameter. A loose gasket won't create a real compression seal, no matter how much KERDI-FIX you apply around it.

What if you skip it?

KERDI-FIX sealant alone can work on small penetrations, but pipe seals are the correct engineering solution and are required for full Schluter Shower System warranty coverage. For the cost of a few dollars per pipe, there's no reason to improvise.

Pairs with

• KERDI waterproofing membrane (any roll or width)
• KERDI-BOARD shower assemblies
• KERDI-FIX sealant (backup seal around the gasket perimeter)
• KERDI-BAND (for sealing around the flange if extra coverage is needed)
• KERDI-SEAL-MV mixing valve seal (for the valve itself)

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