Using Kerdi Shower Pan With Cement Board Walls (Is It Feasible?)

If you have decided to use the Schluter shower system, then it’s pretty obvious that a Kerdi shower pan should be installed with Kerdi board walls. However, can you install a Kerdi shower pan alongside cement board walls? Let’s find out!

Kerdi shower pan

Can You Install Kerdi Shower Pan with Cement Board Walls?

Of course, you can install a Kerdi shower pan with cement board walls. However, the cement board walls must be layered with a Kerdi membrane to prevent water or moisture from seeping through.

In most bathrooms, you will likely find cement board walls. If these are in great shape, you don’t have to swap them with Kerdi board walls. This also keeps your bathroom renovation costs low.

A cement board is an ideal type of material to use in shower walls with a Kerdi pan. It’s pretty durable and can withstand moisture exposure.

The only problem with the cement board is that it’s not waterproof. That is, it will allow water or moisture to pass through.

If you will use it with a Kerdi shower pan, you should cover it with a waterproofing product, preferably – the Kerdi membrane.

Kerdi board

Which Should You Install First: Kerdi Shower Pan or Cement Board Walls?

Now that you know a Kerdi shower pan can be installed alongside cement board walls, it’s time to get into the nitty-gritty.

One of the obstacles most DIY folk usually encounter when building such a shower setup is determining which of these two should come first.

The best way to create a waterproof shower is by installing the Kerdi shower pan first. The cement board should go over the shower pan and not behind it.

If you look at the Kerdi shower pan, you will notice a level lip. That should be the starting point of your cement board walls.

Placing the cement board’s edge on this lip will enable water to swiftly run down into the pan. If you install the cement board walls first, there is a high chance of water running behind the shower pan and damaging the surrounding materials.

How Does Cement Board Compare to Kerdi Board Walls?

At the beginning of this article, I mentioned that the preferred shower setup would be the Kerdi shower pan with Kerdi board walls.

But because cement board walls are also an ideal option, it’s only fair that I share with you a comparison of these two wall materials and their performance.

Both Kerdi board and cement board walls are compatible with Kerdi shower pans. They are also ideal tile underlayments, and you can get them in multiple sizes. However, there are a couple of differences between these two materials.

Cement board is the most popular wall material in showers because it’s cheaper and more durable than Kerdi board. Kerdi board, on the other hand, does have its highlights, such as being lightweight, water-resistant easy to cut and install.

Therefore, if you are yet to buy cement board for your shower walls, it’s advisable to weigh the pros and cons of the Kerdi board. Both options are ideal for building walls over your Kerdi shower pan.

How Do You Waterproof Cement Board Walls Fitted Over Kerdi Shower Pan?

Everyone in the construction industry loves cement boards because of their unique properties. Unfortunately, it is not waterproof, even though it is water-resistant.

Due to this reason, if you have decided to use cement board for your walls over a Kerdi shower pan, you need to waterproof them to prevent leaks.

There are plenty of waterproofing products out there, but a Kerdi membrane should be your top pick. A Kerdi membrane will be more compatible with the Kerdi shower pan than other waterproofing products.

Since Schluter makes both products, you can enjoy their warranty on your shower system. This is something you may not get when you mix two waterproofing systems.

So, as tempting as choosing a cheaper waterproofing solution for cement board walls may be, please stick to the Kerdi membrane.

Cement board

How Do You Transition from Kerdi Shower Pan to a Cement Board Wall?

As you install the cement board over the lip of the Kerdi shower pan, there will be a joint that needs to be sealed.

To create the perfect transition, you should install a fiberglass mesh tape with some thinset. This should create a smooth and durable joint.

It should then be covered with a Kerdi band to ensure water doesn’t seep through. You may also need some Kerdi Kereck for the corners.

These four materials will provide a seamless and waterproof transition between cement board walls and a Kerdi shower pan.

Please avoid using another waterproofing product like RedGard over the Kerdi shower pan and cement board wall transitions. This could void Schluter’s warranty, and the joint may not be adequately waterproofed or sealed.

The other thing you must remember is that the seam between a Kerdi shower pan and the cement board wall must be sealed.

No matter how small it is, if you leave it exposed, there is a considerable chance that water will seep through it and may damage the underlying materials.

While we are still transitioning from a Kerdi shower pan to a cement board wall, you should familiarize yourself with the recommended size of the gap between these two.

The joint should be around ¼ inches. It shouldn’t be too big, nor should the cement board sit flush with the Kerdi shower pan lip.

How Effective Would a Kerdi Shower Pan Be with Cement Board Walls?

A Kerdi shower pan would operate efficiently regardless of what is in the wall if installed correctly. However, if you want your entire shower system to be functional, you need to be very keen when installing both materials.

As for the shower pan, follow Schluter’s instructions on installation. Ensure that you get the correct fit and proper drainage slop.

The cement board needs to be screwed firmly to the wall. It also needs to be waterproofed because it allows water to pass through.

When transitioning between the two materials, follow the tips I have shared with you, and your shower should operate efficiently and optimally.

Do You Need Professional Help to Install Kerdi Shower Pan with Cement Board Walls?

If you are a DIY enthusiast with some slight experience with shower pans and cement boards, this should be an easy project for you.

From the above, it’s pretty obvious that installing a Kerdi shower pan with cement board walls is an easy process. All you need are the right set of materials and some proper guidance. I have already provided you with the latter.

You don’t need to hire a contractor to install a Kerdi shower pan and cement board walls for you. But if you are too busy or don’t enjoy engaging in DIY projects, it’s better to call an expert to install the shower for you.

This will ensure you avoid blunders resulting in costly damages and repairs. Don’t forget that hiring an expert will cost you a few dollars.

What Other Types of Wall Boards Can You Use with Kerdi Shower Pan?

A cement board isn’t the only type of wall you can use with a Kerdi shower pan. We have already mentioned the Kerdi board as the number one alternative.

More options include fiber cement boards, glass mat gypsum boards, and foam backer boards. These three alternatives have additional features, such as better water resistance, competitive pricing, and ease of installation.

As you decide whether you can use cement board walls with Kerdi shower pans, do not overlook other wallboard materials.

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