Introduction: DIY Floating Cardboard Shelf With HIDDEN STORAGE!

About: I've been making Instructables since I was 13. Now, I mostly make videos of my projects, however I'm still active here, so don't hesitate to reach out! Sick with a deadly disease called DIY-itis!

As always, humans use stuff incorrectly. You don't put stuff on a shelf, you put stuff inside a shelf. Still wrong. See?

Well, never mind that nonsense - in this Instructable, I will show you how to make your own cardboard "end-grain" shelf that contains a hidden storage compartment, and floats... Or at least fools you into thinking that it floats!

In the beginning, I thought of making an opening from the side, but then it would be harder to make, remove items, and I wouldn't be able to put many items inside.

Even if this isn't what you'd call "pretty", I think you still might find this Instructable useful, since I do show how to mount a shelf, or anything else on a wall without bolts or anchors, how to make a duct tape hinge, and many more useful tips for working with cardboard :)

(Watch the YouTube video: LINK FOR MOBILE VIEWERS!)

Step 1: What You'll Need:

Below is a list of everything you'll need to complete this project. You should be able to find the parts in a hardware store, on eBay, or maybe outside, on the sidewalk that's near your house! If you don't see something that you think should be here, or would like to know more about a specific tool/part that I used, feel free to ask in the comments.

I made it for FREE since I already had everything that was needed on hand.


Hardware & Materials:




Tools (+Attachments):

  • Knife
  • Scissors
  • Pencil
  • Ruler
  • Caliper
  • Hot glue gun

Subjects: Organization, And, ummm, Cardboarding...?

Approximate Time: ~10 hours, or way less if you use thicker cardboard, and a quicker method for cutting the cardboard (e.g. tablesaw, CNC, paper cutter, etc...)

Difficulty: Fairly Easy


Step 2: How Big?

The biggest item that I'm planning on storing inside the shelf is my iHome speaker, whose size is 4.5x5.5cm.

Everything else is going to be smaller than that, so I think the inside should be 6heightX25lengthX7width, in centimeters, of course. To make things a bit more complicated, the outside should be 6.5heightX27lengthX7width, in centimeters again, without including the top. Again, these really are just numbers that I came up after a bit of thinking, so I might be doing wrong.

What I learned:

  1. The shelf should be more shelf looking. Most shelves are longer than they are thick...
  2. I should have left a bit more cardboard. The difference between the inside measurement and the outside should have been bigger, meaning that the shelf would be a bit stronger.

Step 3: Cutting the Cardboard

I've just replaced the top of my desk. I love how it looks, but unfortunately, it's really soft, so it looks like it would be easy to scratch. To keep my knife from scratching it, I just cut over a piece of glass (salvaged from a printer, of course!), and to minimize mistakes, I used a metal ruler to guide my knife in a straight line.

I made sure to cut it in a way that exposes the "endgrain", since this is what would show when looking at the shelf from the front. 15 pieces of cardboard later, I moved on to the next step

Bonus points if you don't cut yourself even once!

Step 4: Cutting the Insides of the Cut Cardboard Out!

Without completing this step, the shelf wouldn't have been hollow, meaning that there wouldn't be any room for storing stuff!

I put one piece of cardboard aside, and the marked 0.8mm from every side of all 14 pieces (1 is the bottom). This doesn't need to be completed extremely accurately, but I found that scratching (I believe scribing is the correct term) it slightly with a caliper and then going back with a pencil works best.

To cut out the inside, I tried cutting through the side with scissors and then gluing it back together. I also tried drilling a hole in the middle and then cutting it out, but I still think the first one is the best.

If you have an idea for a method that would be better than this, I'd love to hear it since the caliper does tend to ruin the endgrain, and all of that cutting is quite exhausting.

Step 5: Gluing the Cardboard

To be honest, this step is k̶i̶n̶d̶ ̶o̶f̶ very uninteresting. Gluing and stacking, gluing and stacking...

I've read online that CA glue doesn't work well for gluing cardboard, however, in my experiments, the bond was stronger than the cardboard itself. Quite a bit of gluing, as shown in the pictures.

I glued the bottom on too.

Step 6: Congrats on Your New Fingers!


Don't visit hardware stores at this time, as the store manager might think your fingers as big globs of dried up super glue, and throw them away.

Not fun.

Step 7: Mount It Onto the Wall! No Need for a Hammer Drill!

The reason for why I'm using magnets instead of screws/bolts and anchors is because if I ever remove this shelf, the wall will need a retouch (spackle and paint) anyway, but using magnets is way easier. Tadaaa!

After choosing the location that I wanted, I used CA glue to stick 2 HDD magnets to the wall. I chose a position that was comfortable enough to reach from my bed, yet also covers the hole in the wall, until I get it fixed. I then hot glued the washers onto the cardboard shelf (right now, a box, that is).

I later added an additional magnet for extra strength.

Step 8: The Top (& DIY Cardboard Hinge)

I cut another piece of 27x7cm piece, but this time out of some really hard cardboard.

To make the hinges, so the shelf could actually open, I decided to use duct tape. I stuck a small strip of duct tape to each side of the back of the shelf, and to the top. Since the back of the shelf is actually mostly endgrain, the duct tape wasn't really able to stick, so I added a tiny bit of hot glue. My hot glue gun was hot anyway, so why not?

Overall, this has worked out surprisingly better than I thought. Make that way better!

Step 9: Done!

See it in action, on Youtube!

I don't recall ever working with so much cardboard, but this was a nice experience. It didn't turn out as well as I thought it would, but that's also OK. I can always modify it, and improve it so it fits my needs better.

I will be giving away free Instructables memberships to members that make their own cardboard shelf with hidden storage. Will you be the first one?


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I read ALL comments, and reply to as many as I can, so make sure to leave your questions, suggestions, tips, tricks, and any other ideas in the comments below! - Thanks!

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