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Proven Way to Extend ANY Schluter Shower Tray

Schluter shower tray installation is very easy. But sometimes customization is needed. For example, when the existing shower is bigger than the Schluter tray sizes available.

So in this tutorial, you’ll see how to extend any Schluter shower tray using a dry pack.

Let’s dive in!!

Why Use the Schluter KERDI Shower Tray

I get this question a lot. The primary reason any DIYer or professional should use a Schluter KERDI shower tray is this: they work.

First, prefab shower trays are sloped properly. This means that water will drain from the four corners to the shower drain.

How to trim Schluter shower pan
Schluter Shower Tray

Second, Schluter systems shower tray options come in different sizes. This makes choosing the right one fairly simple.

Third, waterproofing the tray is easy because there’s already a waterproof fleece on the surface.

Finally, they’re affordable and the Schluter shower drain is, in my opinion, the best because it’s solvent welded and provides ease of use when setting shower tray tile.

How to Measure Drain Cutting

But on top of all this, every Schluter shower tray can be cut down or extended…as I mentioned earlier.

Most Reliable Method for Extending Schluter KERDI Shower Tray

Entending or enlarging the Schluter systems shower tray is done with dry pack mortar. What is a dry pack mortar?

It’s Portland cement and sand. One great pre-made option is Mapei 4-to-1 Mud Bed Mix – this can be found at most Lowe’s or tile supply shops.

Mapei 4-to-1 Mud Bed Mix

Does Schluter approve this method? Yes, the Schluter Handbooks absolutely show this method when installing Schluter shower trays.

But here’s one annoying caveat: cure time. Dry pack mortars require curing before any waterproofing can begin. For example, Mapei recommends letting their Mud Bed Mix to cure for at least 24 hours to allow water to evaporate.

Shower Deck Mud Tips

Skip this step and you might sabotage your shower remodeling project.

Authoritative Step-by-Step for Making Schluter KERDI Shower Trays Bigger

While it’s easy to make any KERDI shower tray bigger, there are specific steps. So here’s the authoritative guide:

  1. Apply modified thin-set to the substrate…this allows dry pack to bond
  2. Mix Mapei 4-to-1 Mud Bed Mix…use 2 quarts per 55 pound bag
  3. Pour dry pack over modified thin-set and tamp
  4. Screed dry pack to accommodate 1/4″ of slope per linear foot
  5. Smooth dry pack with steel finishing trowel and allow to cure
  6. Apply Schluter ALL-SET to cured dry pack and waterproofed shower walls using KERDI trowel
  7. Embed KERDI membrane into thin-set and smooth with 6-inch joint compound knife

Here’s a terrific short video to help you visualize the process

What’s Next

Installing Schluter shower tray components is easy, especially if you know the steps.

But if you need help with shower waterproofing, check out our step-by-step online courses – I guarantee they’ll reduce your anxiety and prevent you from burning out during a bathroom remodel.

Let me know if you have any questions and I’ll do my best to help.

Hope you have an awesome day!



Schluter Shower Tray

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