How to prep a shower for tile with Schluter Kerdi

Learn how to prep a shower for tile with Schluter Kerdi to waterproof any shower.

Prepping a shower for tile is a very important step in having a waterproof shower. And guess what, there are many different ways to do it. So this is how I prepped a shower for tile with Schluter Kerdi.

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Like I said there are different ways to prep a shower. There is the backing which is either cement board, Dunshield, or another material. After is the shower pan and this can be a premade one, cement one, or just a tray that has the slope. Next is the waterproofing and again more options like red guard or some types of membrane.

See there are a lot of different options but this is a post about the Schluter Kerdi shower system so let me share how I prepped our shower for tile using this system.

WHY I PICKED SCHLUTER KERDI

First I found Schluter Kerdi because of a plumber that only recommended using this system. After researching for myself I agreed it was my best option. And here is why:

the system is completely waterproof (even the floor drain)
the shower pan (tray) already has the slope so NO messing that up!
it’s made for the average DIYer to install

I do want you to know that this is not the cheapest option. It’s about $500 for the whole system. My cost was slightly more because of my half wall and the niche. But let’s move to the process of installing the Schluter Kerdi shower system.

PREP A SHOWER FOR TILE WITH SCHLUTER KERDI SHOWER SYSTEM

SUPPLIES:

Schulter Kerdi Shower Kit (found at Home Depot)

OR buy everything individually

Schluter Kerdi membrane (this was enough for a 36″x5′ shower)
Schluter Kerdi shower tray
Kerdi Drain
Schluter Kerdi band
curb (or use 2×4’s wrapped with your backer board choice)

PLUS you will need these items for either option

mortar (the ANSI A118.1 kind)
2″ test plug
Schluter Kerdi niche (optional)

TOOLS:

bucket
mixer
drill
tape knife
trowels
trowels
razor

Find the list of tools we use.

SIDE NOTE: I did not purchase the kit because I needed the adaptor drain and I was building the half wall so I did not need the whole curb.

TIP: Make sure to have all the plumbing ready before starting this process. AKA: have the shower faucet valve installed and maybe your drain.

INSTALL THE BACKER BOARD

The first step of a shower (after framing and installing the plumbing) is installing the backboard. We decided to use Denshield because it is easier to use and has a moisture barrier (aka: mold-resistant).

SIDE NOTE: We used two 2×4’s for our shower curb (bottom was presser treated and top a regular 2×4) then wrapped the boards with Denshield.

Also, make sure if you are using a niche to have that area not covered in backer board and install the niche after!

LEVELING THE FLOOR

The floor of our shower was not level because we replaced all of our drain lines. So before installing anything the floor needed to be leveled. This was not as difficult as I thought it would be. See my post on how to level a floor here.

INSTALLING THE SCHLUTER KERDI DRAIN ADAPTER

For this shower, we used the Schluter Kerdi drain adaptor because we already had a drain cemented into the floor.

But before I actually installed the new drain, I cut the shower tray to the size I needed (our size was about 54″ and the tray was 60″). To cut the tray, I used a razor blade and square. Then I tested the fit and adjusted if needed. Now back to adding the drain.

The drain kit comes with instructions but I personally love videos so here is the Schluter’s instruction video on installing the drain adapter.

But so you know it was as easy as they made it look and I only installed the adapter ring at this time.

INSTALLING THE SCHLUTER KERDI MEMBRANE

Because this is my first time EVER tiling a shower, I am going to recommend you watch Schluter’s instruction video on installing the Schluter Kerdi shower system. This will explain the whole install process.

Also, it took me 6 hours to install the system.

I decided to cut out my pieces first and this was easily done using scissors.

Next was mixing the mortar. TIP: Make sure you are using the correct type of mortar, it needs to say unmodified thin-set mortar ANSI A118.1. The ANSI A118.1 is the most important part and will be on the bag.

Then I installed the membrane as the video demonstrated starting with the walls first, adding the tray, and waterproofing the corners. The most difficult part for me was the corners but after some practice, it did get easier.

TIP: Place the 2″ test plug into the drain so nothing falls into the drain.

Here is my shower after 24 hours of dry time.

Next is testing the shower. To do this, make sure the shower floor is clean and tighten the 2″ test plug into the drain. Then fill the shower bottom with water (at least an inch deep) and mark the spot. Let that set for 24 hours to make sure everything is waterproof. Here is another Schulter Kerdi video on performing a water test.

SIDE NOTE: This membrane is made so that you could shower with just the membrane (NO tile) and have no water issues.

And that is how someone with NO tilting experience installed the Schluter Kerdi shower system. Hope this helps you when tiling a shower because prepping the shower the correct way will help the shower to last a very long time.

Also be on the lookout for my experience tiling for the first time!