Build a Granite Shower Curb with a Prefab Granite Backsplash

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Building a granite shower curb in preparation for glass in the walk-in shower was my greatest fear when remodeling the master bathroom. The plan was to have a shower curb running the distance of the room and a freestanding glass wall on the shower curb (as pictured). The requirements are pretty intimidating:

• The curb needs to be level.*
• It needs to be 90° from the wall.
• The wall needs to be exactly vertical.
• The curb needs to be sloped towards the drain so water immediately drains off towards the drain. This also has the major benefit of minimizing slipping on the curb (and water draining outside) when you’re getting out of the shower.*
• Minimize the amount of grout lines on top of the curb so that cleaning is easier. Water does not pool in these low spots leaving hard water stains when they don’t even exist! More importantly personally–admittedly, a sucker for aesthetics–less grout lines are so much easier on the eyes.*

Three different kinds of stone were already incorporated into the design: 18 inch travertine tile, 12 inch Blue Pearl granite, and flat cut river rock for the bottom the floor of the shower. I chose a prefabricated Blue Pearl granite countertop for the vanity and the bench seat, but I am counting that along with the 12” tile since it is the same material.

Introducing any other kind of tile seemed like it would be too much.

I certainly did not want to use the 18 inch travertine tile. First, it is a more porous stone and softer than granite. The outer edges would be more susceptible to chipping, even if I chose to bullnose the edge. On top of that since the top piece would extend all the way to both sides of the curb, eliminating two more grout lines on top, it would be subject to more stress than normal floor tile. Why? Because there are no tiles around it to push back when you do a Risky Business dance move on the curb top edge. I know this is how many showers are built and I’m probably overthinking it, but that was my thought process.

Would repeated sideways pressure of a heavy person be enough to pop the top tile off the mortar attached to Schluter Kerdi lined curb base?**

Bullnosing a straight line over a more than nine foot distance on two sides would be an exercise in insanity. Perfectly straight lines matter, making a bathroom truly showroom worthy! A metal profile edge (we have had good experiences with Schulter profile edges) would solve this problem. They are a perfect edge finish, but it is another edge to catch water on top of the curb.

A cross section of a shower curb using a Schluter profile to finish the curb top.

Note, Schluter-QUADEC, pictured above, is only one of the many Schluter profile offerings. There are rounded and thinner options as well. The Schluter products are designed to snugly fit next to the tile so as to minimize the grout line between the profile and tile.

The second reason not to use the travertine is because it is a lighter color tile and it is more likely to stain from foot traffic. Or if a glass of red wine shatters on it!***

Using river rock was never even in question. Getting the uneven stones exactly horizontal would be an absolute nightmare!

That left the 12” blue pearl granite tiles, but a grout line every 12” was more than I wanted to look at everyday.

I had heard of solid surface granite shower curb options, but had not had a chance to really investigate.

When the prefabricated granite countertop came in I was thrilled: it came with a 6-inch prefabricated backsplash!

I knew I had found my answer!!!

The walk-in shower was going to have a bench seat alongside the double vanity. Transitioning from a 1-inch thick prefabricated backsplash to 1/2 inch travertine would look awkward.

The arrow is highlighting where the prefabricated granite backsplash would end against the travertine tile surround in the rest of the bathroom.

Here is the close up of the awkward transition depth:

Yep, awkward.

Second, I wanted to have a repeating mosaic theme throughout the room. The design requires that some of the mosaic would show up between the two sinks.

It is not hard to come up with a different backsplash solution for the vanity area. There are so many different beautiful mesh backed mosaics or other eye-catching kinds of tile on the market.

So, the intention was already not to use the prefabricated backsplash as a backsplash. In fact, the backsplash was not going to be used at all otherwise. Translation: since it was going to go to waste it is a FREE curb threshold solution.

It was the perfect solution for the walk-in shower curb top. As you can see from the checklist above it certainly minimizes the grout lines. There aren’t any!

Discovering this new use for a prefabricated granite backsplash was totally unexpected, but it is the absolutely perfect solution.

Gotchas with choosing a backsplash as a curb

• Of course, by choosing an unusual use of the backsplash, there is still a little extra work involved. Prefabricated only means it is polished on one of the long edges. The other edge, which is now fully visible, needs polishing. Get ready to pull out your diamond polishing pads and low RPM variable speed grinder.
• This also means making sure you consciously choose and install which side faces out. I’m proud of my polishing abilities, but I’m not gonna lie–I’m not as good as a machine built specifically for this purpose. The prefabricated side faces the parade of traffic to the toilet and closet. My polish job is on the inside of the shower.

• The shower is longer than the piece of granite. I created the last little extension from the bench seat scrap, which was already scrap from the vanity. Stashing the second fabricated piece on the end between the bench seat and vanity where it would be less obvious makes the most sense.

The only grout line on the granite shower curb, hidden away between the shower bench and vanity. Also, there is an optical illusion going on there with the Delorian Grey grout–it looks like it is at an angle, but it is not.

• This is a two person job. Even a 6” piece of granite is super heavy. Make sure you have help handy when you need to move it to polish and set it into place.
• Prefabricated backsplashes normally have a mirror finish. Meaning it is slippery when wet. I step over the curb and not on it when I get in and out of the shower. However, you could send it to a fabricator for leather finish, providing more grip on the surface.

Often thought as a minor detail, how you decide to finish the threshold of your walk in shower curb is a decision that takes some thought. How you want it to look and stand up to continuous use are all factors in the final choice. If you are already using a prefabricated granite countertop, using the accompanying granite backsplash as a shower curb could be the perfect answer you are searching for!

You can check out prefabricated options at Floor and Decor or your local granite shops.

For a little more discussion “in person” check out the following video:

*Similarly, you can verify if a shower curb top is installed properly with the checklist in this video:

**I’m by no means calling myself fat, even with the additional pregnancy weight. My husband either! We are keeping trim by DOING all these house remodel projects ourselves. However, I have no idea who will own the home next. Or if we turn this house into a vacation rental it needs to be bomb proof.

***Yes, I’ve had a girlfriend over for drinks while we tried out different curling irons and wedding hairstyles when I was about to get married. Given, she likes white wine and I like red, so odds were only 50%. What were you thinking? 😉