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How to Install a Corner Shower Shelf into an Existing Tiled Shower

Illustration for How to install a Corner shelf post featured image

by Steve

Yes, you can easily install corner shelves to an already tiled shower!… and I’ll show you how to do it in this post.

I’ll give you step by step instructions on how to install the rb3 Corner Shower Shelf – an innovative, modern, stainless steel corner shelf by Redblock Industries.


I install this shelf routinely because it’s a retrofit shower shelf that has a truly “built-in” look. It’s also the only shower shelf made from super corrosion resistant 316 stainless steel, AND you can easily install it into non-square shower corners.

Unlike most of my other posts, this is going to be a very small scale shower remodel. No demo, no remodel, no special skills or tools… just a quick, budget shower improvement idea to give you a bunch more storage and a cool new look.

If you don’t already know me – I’m Steve Gehrmann, a bathroom remodeling professional with 20+ years bathroom remodeling experience. I should also mention that my brother and I designed the shelf I’ll be installing (rb3 Corner Shower Shelf).

So let’s get to it!

Topics Covered:

Installation Video

Step1 – Determine the height of your Corner Shower Shelf

Step 2 – Mark out Install location

Step 3 – Remove the Grout

Step 4 – Clean out Notches and Dry Fit

Step 5 – Apply Silicon, Install Shelf

Installation Video

I have included a complete install video below, but I would recommend that you also check out the install steps below the video. These steps include a bunch more info that will enhance & clarify the video steps.

Step 1 – Determine the height of your Corner Shower Shelf

Your first corner shelf installation step should be to decide how high you want your shelf to be from the shower floor or tub edge.

If you’re planning to install it on the wettest side of the shower (valve and shower head side), I usually recommend to my clients that it should be installed around chest height (around 48″).

This is based on a common preference to keep the shelves out of the primary “splash zone”. This way they don’t get too drenched during showering but are still within easy reach.

If you want to install two corner shower shelves, 48″ is also a pretty good height to start, but you may want to start a little lower if you’re planning to install three shelves, or the top one may get a bit too high to reach.

Of course if your planning to install on the opposite side of your shower (outside the splash zone), your lowest shelf can be lower… any height you want really.

If you want to install more than one shelf, you should consider what you’re planning to store on your shelves to determine the distance between them. I generally install them 10″- 14″ apart, depending on the homeowner’s needs.

Step 2 – Mark out Install location

The Redblock rb3 corner shelf has two, 2″ tabs that insert into the grout line space, so you will need to mark these out on the grout line so you know where the grout should be removed.

This shelf is very well suited to installation into shower corners that are not square, but the install location will obviously vary slightly if the wall isn’t perfectly square.

As such, you should check your shower corner with a framing square before you mark out your install leg locations.

If the shower corner is more than 90 degrees, the install leg positions will be slightly closer to the corner. If the corner is less than 90 degrees, the install leg locations will be slightly further away from the corner.

In my experience, even if the corner is super wonky, the most I have ever adjusted the install location is 1/16″ one way or the other.

Assuming the shower corner is 90 degrees, the location of the grout cutout locations are:

Left installation leg: 4″ – 6″ from the corner.

Right installation leg: 2 11/16″ – 4 11/16″ from the corner.

Step 3 – Remove the Grout

As you can see in the video, my first grout removal step was to drill some pilot holes to 1/4″ depth.

But unlike the video, I would suggest that you drill at least four or five pilot holes within the grout removal area before attempting to use a grout removal tool. The more grout you remove with the pilot holes, the easier it will be to remove the rest.

Be very careful not to drill deeper than 1/4″ because you may unintentionally drill through the waterproofing membrane.

If you follow this pre-drilling strategy, you can easily remove the rest of the grout with a simple and inexpensive grout removal tool. You can buy this hand tool online or at any home improvement warehouse to remove the rest of the grout quickly and efficiently.

I chose to use an oscillating saw (multi-saw) to remove the grout. It’s super fast at removing the grout,  but I would only recommend using it if you’ve had some experience with this kind of tool.

Step 4 – Clean out Notches and Dry Fit

After grout removal, be sure to clean out the install notches thoroughly. I generally use my shop vac to make sure there is no debris left, and to keep any dust out of the air.

It’s also a good idea to look into the notches to make sure they are clear of debris. If it’s clear, you should do a quick “dry fit” so you can see it slide into each of the notches.

Always insert the right install leg first and ensure it sinks at least 1/4″ into the install notch. You can also apply a pencil mark, or apply a strip of masking tape at 1/4″ depth, to ensure that the shelf is seated properly into the notch.

There is an angle cut out of the leading edge of the left install leg, to allow it to swing effortlessly into place after the right leg is fixed in place. You will know that the left leg is seated properly when the angled section of install leg disappears just below the grout line.

If the shelf inserts properly into both notches, remove it again temporarily so you can do a final cleaning, and apply the silicon.

I also use a soft cloth to wipe any dust off the tile face. This will ensure the silicon adheres well to the tile above and below the shelf.

Step 5 – Apply Silicon, Install Shelf

After the final cleaning, it’s now time to apply silicon into the install notches.

Be sure to apply a liberal, uninterrupted bead of silicon into both notches. Don’t be too worried about how much you apply here. The excess will squeeze out when the shelf is inserted.

Now simply insert the shelf legs into the install notches, the same as you did during the dry fit.

All you need to do now is clean up the silicon that squeezed out when you set your shelf in place. You can do this with a silicon caulking tool or your finger if you feel comfortable with this (like I do).

I usually apply a very small bead of silicon around the shelf install legs after I complete this step but you don’t need to do this if you feel that enough silicon squeezed out above and below the install legs during installation. The point here is only to ensure that a tiny amount of silicon entirely surrounds the install legs.

If you’ve created a bit of a mess during silicon application you can use denatured alcohol, or 90% (or higher) rubbing alcohol to remove the silicon residue. It does a very good job removing silicon so be careful not to disturb the finished bead around the shelf legs while the silicon is still wet.

Congratulations!!… Your Redblock rb3 Corner Shower Shelf is Installed!

If you’d like any additional info on installing this shelf, please visit our rb3 Corner Shelf Install Guide.

Wrap Up

I hope I’ve demonstrated how easy it is to add more storage to your existing shower with this truly unique and modern metal shower shelf.

No more need to build your own custom corner shower shelf or hang a temporary corner shelf with suction cups or screws.

This shelf installs quickly and easily and looks like it’s always been there… a beautiful, strong & permanent corner shower shelf solution!

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