Built In Bookshelves | IKEA Billy Bookcase DIY

Last Updated on May 20, 2023 by lindseymahoney

I gotta be honest, I wasn’t sure I was going to finish week 4 of the One Room Challenge! In the final minutes, I finished my Ikea Billy Bookcase hack and I am so proud of how it came out.

How to create a built-in bookshelf using two Ikea Billy bookcases | Building Bluebird #diyhack #homerenovation #ikeahack #shelfie #bookshelfstyling #organization

This IKEA Billy bookcase hack came with a few challenges, but this DIY adds a ton of storage and really looks sharp in my son’s bedroom.

How to create a built in bookshelf using two Ikea Billy bookcases | Building Bluebird

If you are new to my blog, welcome! I frequently participate in the One Room Challenge where a group of DIY enthusiasts makeover a space in their home in 6-8 weeks.

Each week we share our progress and projects tackled and for this particular challenge, I am working on my son’s bedroom!

This week (4) of the challenge included Memorial Day Weekend and my husband’s birthday, so I had no time to work on this project over the weekend. But I digress, I made it through and can’t wait to share my experience this week.

Do you love watching these rooms transform in 6 weeks? Check out the dining room transformation from the first time I participated in the ORC and our moody master bedroom makeover from the Fall of ’20!

Popular Built-In Bookshelves DIY | Ikea Billy Bookcase Hack

[ This post includes affiliate links where I receive a small commission on items purchased through these links. All opinions on the products are my own.]

Built-In Bookshelves (Billy Bookcase) Source List

IKEA Billy bookcase (2)
Liquid Nails
Caulk
Wood filler
Sanding block
Toe kick
Frogtape
Baseboard
1×3 wood board
Trim
Quart of paint color-matched to the bookcase, satin
Paintbrush

Tools Used

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1 | Assemble Your IKEA Billy Bookcases

I purchased two of the Billy bookcases for my son’s bedroom and easily assembled them. Determine where the bookcases will go in the room and attach them to the wall so they don’t tip over.

2 | Attach the Baseboard

To create the “built-in” look, you will install the trim as if the two bookcases are actually a single piece of furniture.

I began by measuring the distance from the wall to the end of the second bookcase. This measurement gives me the length of the baseboard trim piece.

The first challenge I encountered with this built-in bookcase DIY was the gap between the bottom shelf and the baseboard.

Luckily, I had some leftover wood scraps in our garage and discovered that the baseboard toe kick (dark gray piece) used on our kitchen cabinets filled the gap perfectly!

First, I cut the filler board to fit in the gap. Then I applied liquid nails to the board and taped it to the shelf so it could dry.

Next, I cut the baseboard and installed it with a nail gun using finishing nails.

3 | Attach Vertical Trim Pieces

I used the same kitchen cabinet toe kickboards to cover the center seam, left edge, and right edge of the bookshelves.

Each vertical finishing trim piece is a different width and to cut each one I used a table saw. My cuts were not perfect, but my hope was that the caulk would hide a lot of the mistakes! It did. 🙂

4 | Add Finishing Trim to the Top of the Built In Bookshelves

Because the top shelf is slightly inset, I had to sandwich two toe kickboards to the top shelf so that it aligned with the vertical trim boards.

All of the finishing pieces are now flush and it is really starting to look like a single piece of furniture!

I spent a good part of the day trying to make leftover crown molding from our kitchen work but I could not figure out how to cut it!

I decided to use a simple piece of 1×3 wood to finish off the top of the built-in bookshelf. This created a clean, modern look and I am really pleased with it.

5 | Caulk the Built-In Bookshelf Seams

Where the ends of the bookshelves met the wall, I added a small trim piece to give a more finished look. Finally, I took caulk and filled all of the cracks and my mistakes! Haha.

6 | Sand and Paint Built-In Bookshelves

When the caulk dried and the bookcase was sanded smooth, I painted the new trim on the bookcase to match the original piece.

To get the exact color, I brought one of the shelves to my local Sherwin-Williams store where I had a quart color-matched. The satin sheen blends seamlessly with the bookshelf finish.