Introduction: Diagonal Bookshelf

About: 23, college student. Love a good challenge build, most of my projects are for myself or friends. If you have any questions about anything feel free to contact me at

I wanted a huge bookshelf for the wall in my bedroom. I decided against the traditional style and went with something more modern and unusual. I searched online and came up with the idea to make a bookshelf that’s essentially tilted on its side. Like a wine rack, the shelves are set at a 45 degree angle.

Step 1: The Design:

Arguably the most important step, its very important to determine how big you want the shelf to be. I wanted mine to be floor to ceiling and take up as much of my wall as possible, while still being square. I opted for a 9’ x 9’ square as the size of my bookshelf. I did some guess work to determine how big I wanted each “shelf” or “hole” to be. 18” seemed to be the magic size that I liked the look of. Doing some simple drawing and math, I calculated how long each section of board will have to be by using the Pythagorean Theorem and ratios.

Remember: A^2 + B^2=C^2 !

Step 2: The Supplies:

By drafting out my design, I was able to calculate about how much supplies I would need for this project:

20 8’ x 10” boards (Lowes’ didn’t carry longer boards in the wood I preferred).

40 1 ½” L brackets

a box of 1 ¼” wood screws

and to paint it I needed:

a gallon of black paint

dry wall spackle

sand paper

small rolling paint brush

2” foam paint brush

The supplies obviously depends on the size of your shelf and preference of style of building. The spackle was to fill knots and screw holes so the entire shelf would be smooth.

Step 3: The Build: Part 1

I started by making my frame for the shelf, a perfect square. Remember that the two inside sides will have to be shorter by 2 times the width of the boards so that way the square stays perfect.

I used string and measured out increments of 18" down all the boards and roped out where all the boards will sit.

The string allowed me to get accurate measurements for how long all the boards would need to be, and i generalized the dimensions so all the sides would be the exact same.

Step 4: The Build: Part 2

Refer to the diagram in "The Design" for all the labels of the different pieces:

I worked my way outside in, starting with the small “A” pieces in all four corners. I used a table saw set at a 45-degree bevel and the blade half as tall as the width of wood. I used the fence and set it as close to the blade as possible and ran the corner through both ways to make the 45-degree angle on the end of the boards. After having all 4 ends cut I cut each board to the same length to fit inside “AA”. The “A” pieces are all screwed in from the side of the box and their ends are screwed into “AA”.

Next I started working on the “B” section pieces. Two in each corner need to be cut at a 45-degree bevel. The middle piece is just cut at a 90-degree angle on both sides. I used a chop to cut the ends of the two boards and to cut the middle piece to length. The two side boards in each corner are screwed in from the box and their ends screwed in to the “BB”.

All of the “AA’s” and “BB’s” edges are cut at a 45-degree on the ends and are screwed in from the sides of the box.

The outer half of the shelf is done, the inside will all be grooved together. Essentially by this point, you’ve got the outer square and then at a 45-degree angle you have the inner square.

Step 5: The Build: Part 3

To get the exact spacing right, we measured each section from side to side to fit the boards snug. Once all 6 boards (3 up and down, 3 left and right) we began routing. To line up the grooves, we measured from each end the exact amount of space we choose for the shelf square (we used 18” x 18” boxes, so 18” + the ¾” width of the wood).

To make the jig, we used scrap wood from the project, measured to half the width of the board, and made the gap ¾”, the same as the depth of the wood. We secured this jig to the counter and slid each board over the top, clamped them into position and routed through.

The reason we put the jig on the bottom was because the bit we used had the collar on the tip, not the base of the bit.

Once we routed 3 grooves into each board, we test fit all the boards together on the floor and measured the squares they made, checking to make sure the squares were 18” x 18”.

Step 6: The Build: Part 4

We took these pieces back and fit them all them all into their designated positions. To secure them, we used 2 L brackets per side per board that touched “BB”, excluding the middle board on each side. Where the grooves met, we used flat brackets to screw each side to one other.

Once everything was screwed together, we began to label each piece of the shelf on the back spine of the shelf; this will go against the back wall and not be painted. We labeled all of the pieces because the shelf had to be disassembled, painted, and reassembled.

The outer pieces in each corner- “A”

The outer opposite pieces that support “A”- “AA”

The inner 3 pieces below “AA”- “B”

The board below “B”- “BB”

I then numbered the grooved boards, 1/2/3 up one side and 4/5/6 down the other. I made sure to write the numbers on the grooved boards and on the “BB’s”.

We stood the shelf up to make sure it sat flat, and it sure did! We took the next 20 minutes or so disassembling the shelf and laying out all the pieces in our garage to be painted.

Step 7: The Paint Job:

We decided to paint the shelf in pieces for the first few

I went to Lowes and asked for a gallon of the cheapest black paint, which ended up being a bad idea. I put three coats of this paint on without a very solid coverage. I went back and bought a thicker paint, which covered the entire shelf much much smoother. I painted one coat when the shelf was in pieces, and then touched up everything once it was in place.

Step 8: The Placement:

We got the shelf pieces down into my bedroom, started with the frame and worked our way inward. We screwed the whole thing together, spackled the holes, sanded, and touch painted it for the last time.

We had to cut part of the baseboard so that the shelf would sit flush to the wall. We used an oscillating saw to cut the baseboard, which kept us from damaging the wall.

We pushed the shelf against the wall, and used L brackets to keep the shelf to the wall.

Step 9: The Finish:

We went through a lot of Clorox wipes keeping all the dust off the shelf until we were done, gave it a good wipe, and then put all of the books onto it! The shelf looks great and has plenty of space for storage.

If you have any questions feel free to contact me @

Shelving Contest 2016

Third Prize in the
Shelving Contest 2016