We have a wooden corner unit in our basement that has these triangular shelves on both sides. They’re great for displaying things but I wanted to add some closed storage to the lower shelves, so I had to design some custom boxes.
Once you figure out the angle, which isn’t difficult, it’s actually pretty easy to make the boxes. I covered mine with wrapping paper but you can decorate yours however you choose.
– cardboard box approximately the same size as the shelf
– flat cardboard pieces
– exacto knife, scissors
– ruler, pencil
– glue gun, glue sticks
1. Place a regular piece of paper on the shelf with one edge tight against the side. Bend the opposite side up so that you can press the paper tightly into the corner. Fold the paper firmly so that the folded edge is tight against the side of the shelf. This will be your template for creating the box.
2. Cut the top flaps off a cardboard box (and cut shorter than your shelf space, if necessary). Place it upside down on your work surface. Put your template UPSIDE DOWN on the bottom of the box with the 90 degree angle against one corner. Trace your angle, using a ruler to make the line longer if necessary. Cut this line and down the sides of the box at both ends of the line.
NOTE: If you have other shelves that are exactly opposite the one you start with, you should be able to use the same template, just place it right side up on the bottom of the box instead.
3. Measure the angled edge of the box at the inside of the bottom of the box. This length will be the length of the side piece of cardboard, plus an inch or so for flaps on both ends (for gluing). Measure the inside height of the box. This will be the width of the side piece, plus an inch or so for a flap along the bottom (for gluing).
4. Inside the bottom of the box, trim the inside flap(s) back from the angled edge to make space for the gluing flap on the side piece. Glue down the inside flaps. Check the side piece for fit, adjust if necessary, and glue in place. I glued the bottom edge first, then one side, then the other.
If you don’t want to make a lid, skip to decorating and using the box.
5. Place the box upside down on another piece of cardboard and trace around it. Use a ruler to draw lines about 1/8″ outside of the traced line (for folding). Draw more lines an inch from these lines (or more if you want a deeper lid). Cut on these lines. Cut some of the ends to make small flaps (for gluing). Fold on the fold lines.
6. Check to make sure the lid will fit. Glue the small flaps to the insides of the lid edges to form the lid. I also taped the corners that I felt needed a bit of extra reinforcement.
DONE. Decorate/cover the box however you like, fill it up, and stick it on the shelf.
(No, your eyes aren’t playing tricks on you – we painted the corner unit before I finished the boxes.)