How To: Build a Cardboard Shelf

Upcycling Cardboard By Mallory Williams 04/04/25

What’s the Point?

Reusing and reducing is more superior than recycling. That’s it. That’s the point. 

I often hold on to plastic, cardboard, and glass for a while to see if I can think of or find a project to use it. Sometimes I have to just cut my losses and let it go, but the heart of the creative in me breaks a little bit when I do. There’s just something about saving some trash and turning it into something; anything. We have way too much waste nowadays to just instantly throw everything out, but there’s not a lot of people who think what I think. I know, kind of a pick me moment. But it’s true, most of my friends and family kind of look at me like a hoarder – but I don’t mind holding on to some recycled goods to try to reuse them.

But the thing is with my procrastination mindset , I will do everything in the world except the project I’m actively working on. This paper mache shelf has sat in my apartment unfinished for, um, a couple of months. (or papier-mâché if you want to be bougie, but I will not be spelling it like that- giving pick me again) I had got a new mattress on black friday, because we love a deal in this house, and the bad boy came rolled up in a box. 21st century things. I didn’t want to just throw out the huge box it came in, nor the plastic wrap it came in either. I don’t prefer recycling as it can be a little bit of a scam, I talked about this in a previous blog (https://gogreengirldotcom.wordpress.com/2025/03/24/is-recycling-actually-worth-it/) . Although, it is more focused on plastic; there are similar confusions with cardboard but definitely not as much. One of the biggest things to think of when recycling cardboard : no wax coated cardboard can be recycled, also no food waste on cardboard.

But yes, I always try to give reusable waste a second chance at life. This rectangular box was about 3 feet tall and 1 foot and 3 inches wide. Perfect for a shelf. I actually use it for a shoe holder and then at the top I have some CDs, nicknacks, a plant. It’s literally a whole shelf that I made myself, add an elf – waste to wealth. I just wanted to rhyme for a second. Kind of bars, though.

The Shelf!

1. The Arch 
2. The shelves
3. Shelf Support 
4. The Base

Step One: Have a Vision

Having a vision is genuinely the first part, and the best part, of the whole process. Get creative, if you are having a block; go online for inspo. Look at Pinterest, look at a furniture website perhaps, anything to get those creative juices flowin’.

Step Two: Get to Work

First, I took the 3 foot tall box by 1 foot and 3 inches and cut out one side of it, this is the structure for the shelf 

Then I took the cardboard that I had cut out, and cut it into four squares to use for the two shelf pieces. (section 2 from the above picture of the finished product)

Step Three: Square Time

I tried to cut the squares about the same width of the box so they would fit snug in the box. I took the squares I had cut from one side of the box, and sandwiched some plastic wrap that the mattress came in with a bit of painters tape and hot glue.  I did this to give the pieces more structure.

I then took two old boxes from christmas gifts and put plastic in them again for structure,  and taped them shut, and put them underneath the shelf pieces. (section 3 from the first picture of the finished product) I think a cereal box would have worked as well. Maybe even better. I was a bit worried that the boxes  would be too flimsy but they have held up well. I have secured the boxes with paper mache around the bottom where it connects to the base of the shelf, and the shelf pieces. 

I added two pieces of cardboard with more plastic between it abt 2 by 2 inches for more structure between the white boxes so they wouldn’t bow out. I hot glued those pieces to the shelf piece. I did everything again for the second level of the shelf. 

Step Four: Arch That Thang

For the top arch piece (section 1 from the first picture of the finished product) I used a dr pepper box and used pieces of painter tape to hold it down to the shelf, and glued pieces of newspaper to the dr pepper box to give it more structure. I put an old pillow inside to hold it up to give it more of an arch . But you could also use a new pillow, no matter how young or old the pillow will do the job. 

I used another piece of the Dr Pepper box for the back paneling. I cut it a bit too short so there is a space between the back panel and the arch, but what’s a project without a little bit of uniqueness to it. It’s not supposed to be perfect.

Step Five: Paper Mache and Painting

I used flour and water, and ripped up old coupon pages, for the paper mache. I don’t get a newspaper sent to me, but I have a crazy amount of coupon papers that I use for projects. The dates are old, and I’m not necessarily the biggest couponer even though I should be. A penny saved is a penny earned.

I used paper mache to keep everything together , and actually used a tiny nail to hold one of the shelfs in because I cut one a bit too short so it didn’t fit as snug as the top shelf. 

I covered the whole shelf in paper mache which took forever like that is why this project sat for a good couple of months. This gave the shelf more structure, gave everything the same texture to paint on. Just overall made the shelf – a shelf, rather than just a bunch of cardboard glued and taped together. 

Then I painted the thang and that also took awhile because I had small, baby paint brushes. I would suggest using a paint roller, get serious. I did two coats of black paint and I used some cheap paint from the dollar store but if you want to be more efficient and get better paint, I don’t blame you. Maybe you wouldn’t need two coats, but maybe you still would. Do whatever makes your heart sing. 

So, this was How To: Build a Cardboard Shelf. I am a furniture maker, next I am going to make a paper mache couch and bed frame. Join me next time, and thank you for reading!