DIY Built In Bookshelves Using the IKEA Billy Bookcase Hack

How to make DIY built in bookshelves with glass front Oxberg doors using the budget-friendly IKEA Billy bookcases hack. 

home office DIY built in bookshelves using the IKEA Billy Bookcase hack

We’re no strangers to the IKEA BILLY bookcase hack around here. After our third set of these bad boys that we built in the home office makeover, Robert and I could probably make these DIY projects in our sleep at this point. 

But every time we’ve done one of these hacks, we’ve used a different size or type of Billy bookcase, and with out-of-stock issues popping up at IKEA lately, I thought it would help to make a tutorial for this specific skinny version with glass panel doors so you can adapt to availability. 

See our DIY built in entertainment center using tall, wide Billy bookcases here. Or see our DIY playroom built in bookshelves using short, wide Billy bookcases here. 

They all follow mostly the same steps, but we feel like we’ve officially mastered DIY built in bookshelves with this method. 

Why IKEA Built-In Shelves Are the Best Solution for DIYers

These shelves work beautifully in a living room, playroom, media room, home office, or dining room. Built-ins are a classic design feature that will never go out of style.

Related: Classic Interior Design Trends That Never Go Out of Style

The best part of this DIY project is half of the work is already done for you since you don’t have to build the bookcases from scratch.

If you’re looking for a less expensive way to create a custom high-end look in your home, need lots of vertical storage without wasting space, or just want to try a great beginner-level carpentry project, the tutorial in this blog post will guide you along the way!

assembling IKEA Billy bookcases

How to Make Built-In Bookcases Using the IKEA Billy Hack

Tools

Supplies

(This is what we used, but you can change the number of Billy bookcases and Oxberg doors to fit your wall’s dimensions or needs.)

Notes: Consider the measurements of the length of the wall and ceiling height to adjust the number of bookcases and board sizes you’ll need to create the built-in look.

For reference, we had 8 foot ceilings and our wall was 11.5 feet wide. The top of the bookcase came to about 7.5′ tall leaving 6″ to close the gap with a trim board.

We placed these shelves on hardwood floors, but if you have carpet, I would suggest removing that section of carpet underneath the bookcases.

Steps

Step 1 – Remove Baseboard

To get the Billy bookcases as flush as possible to the blank wall, remove the baseboard and shoe molding trim piece.

Use a utility knife to cut along the caulk lines of the baseboard.

Then, use a claw back hammer and a small pry bar to pull the baseboard away from the wall.

removing a baseboard from a wall using a pry bar and hammer

Step 2 – Assemble

The first step is to assemble all of the boxes of the Billy bookcases, including the height extenders.

Leave the bookcases without the thin backing that comes with them since the back wall will become the bookcase backing since you’re building them in. 

You can keep the height extenders off in the next step until after you anchor the bookcases to the wall. 

assembled IKEA Billy bookcases ready to make into built in bookshelves

Step 3 – Correct Gap

Since the bookcases are designed to have a backing (but it’s best not to have one in a built-in to allow access to outlets), there will be a small gap at the back. 

To make this look a seamless wall of built-ins, measure the bookcase and cut a piece of 1×2 board.

Attach the 1×2 to the back of the bottom of the bookcase along the lower shelves with the finish nailer. 

And the gap is gone! Caulk will fill any cracks later. 

gap at the back of an IKEA Billy bookcase hack
adding a 1x2 to the back of a bookcase to fill a gap to make diy built in bookshelves
filled gap at the back of a bookcase using a 1x2 to make the IKEA Billy bookcase hack

Step 4 – Anchor Shelves

Get the exact measurements of your wall and make sure the bookcases are centered and place where you want them.

Use a stud finder to locate studs in the middle of the wall.

Anchor the middle bookcase into a stud. 

anchor added to the back of a bookcase to keep it attached to the wall

Step 5 – Attach Each Billy Bookcase Together

Use your clamps to tightly hold together the sides of two bookcases.

Then, screw the wood screws through both sides of the bookcases to secure them to each other.

Once you begin adding boards around the top, bottom, and sides of the bookcase, they will do a great job of securing everything together too.

clamping bookcases and attaching them together with wood screws
using clamps to keep bookcases together to attach them with wood screws to make diy built in bookshelves

Step 6 – Build In the Gaps

See that little bit of space around the sides and top of the Billy bookcases?

We want to fill that in with trim work to make the bookcases on the entire wall look like built-in bookshelves. 

attached and anchored bookcases to the wall to make DIY built in bookshelves

Step 7 – Attach 2x4s

In the small gaps, drill 2x4s to the wall and the side of the Billy bookcases. 

using 2x4 boards to brace sides and fill gaps to make bookcases look built in for the IKEA Billy bookcase hack

Do the same for the top of the shelving unit too.

adding a 2x4 board to the top of bookcases to fill the gap below the ceiling for DIY built in bookshelves

Step 8 – Attach 1×4 Boards to Front of the Bookcase

To make the bottom of the bookcases look like one solid built-in piece of cabinetry, attach 1×4 pre-primed boards with brad nails. 

Use a coping saw or jigsaw to cut out the sides of the boards to mimic the shape of the baseboard on the wall.

It doesn’t have to be perfect as caulk can later fix imperfect cuts.

Repeat the process for the top of the Billy bookcases, coping the sides of the 1×4 boards to fit the crown molding. 

adding 1x4 boards to the bottom of bookcases to make them look flush for DIY built in bookshelves
marking the shape of a baseboard to a 1x4 board to cut
using a coping saw to cut out the shape of a baseboard to meet against a 1x4 board
attaching 1x4 board to the bottom of bookcases using a finish nailer for DIY built in bookshelves
1x4 board cut to the shape of a baseboard to make it look flush against the wall

Step 9 – Cut 1×10 Boards to Fit Sides

Since the sides of the bookcases typically aren’t the exact width of a board, measure the gap between the bookcase and the wall and cut down the 1×10 board to fit along the bottom shelf as the face on the sides using a circular saw or table saw. 

trimmed 1x10 board to fit the front of bookcases and fill the gap to make them look built in for the IKEA Billy bookcase hack

Step 10 – Attach 1×2 Boards to Front

Use the finish nailer again to attach 1×2 boards to the fronts of the bookcases to hide the cracks where the bookcases meet together. 

added 1x2 boards to the fronts of bookcases to hide the cracks where they meet

Doesn’t it look so flush and solid now?!

Well, it will once the cracks are filled with caulk and gaps are filled with Loctite foam. 

boards added to IKEA billy bookcases to make them look like built in bookshelves

Step 11 – Fill Gaps, Cracks, and Nail Holes

Use Loctite foam to fill any larger gaps.

We used it to fill the small gap between the bottom 1×4 and the bottom of the bookcases since it was slightly too big for caulk.

Once dry, cut the foam and sand it smooth. 

Use caulk to fill any cracks between the wall and boards. 

Then, use wood filler to cover any nail holes or cracks in the boards where they meet. Let dry. 

wood filler, caulk, and Loctite foam covering gaps, cracks, and nail holes

Step 12 – Sand Smooth

Once all of the fillers are dry, use an orbital sander to smooth it out. 

orbital sander used to smooth out wood filler and Loctite foam

Step 13 – Remove Dust

We used our shop vac to remove any sanding dust from the built ins to make it ready for paint. 

using a shop vac to remove sanding dust from shelves

Step 14 – Paint Boards

Paint all of the visible boards with the satin paint you had matched to the bookcases to make everything look like one solid piece of built in bookshelves.

I discovered Sherwin Williams base white paint is the best match for IKEA white.

You don’t have to apply an entire coat of paint to the Billy bookcases themselves, just the boards so they’ll match them. 

If you do plan to paint your bookshelves, I strongly suggest lighting sanding, applying a shellac-based primer, and using urethane alkyd enamel paint in a paint sprayer.

The final result will make the paint stick to the veneer and keep the paint job as durable as possible. My favorite paint for cabinets and furniture is Benjamin Moore Advance.

Painting the BILLY bookcase built-ins all over a different color from IKEA’s factory finishes does create a statement-making design element with a more custom look. 

Related: The Trick to Paint IKEA Laminate Furniture

Not bad for using an IKEA hack, huh?

newly painted IKEA Billy bookcase shelves to make them look like one solid built in piece

Step 15 – Add Doors (optional)

We wanted to add glass/panel Oxberg doors to the front of a few of the bookcases to provide some concealed storage.

Oxberg doors are designed by IKEA to fit Billy bookcases, but by making these built in, there’s a trick to hang them properly. 

Oxberg doors added to bookcases for concealed storage

Step 16 – Mark on a Combination Square for 1×2 Depth

Since the existing holes on the Billy bookcases are no longer useful for hanging Oxberg doors as they are intended in design, you have to make new holes to account for the depth of the 1×2 boards added to the front of the bookcases. 

Place a combination square against the 1×2 and mark its depth with painters tape. 

using tape on a combination square to mark new depth of hinge holes

Step 17 – Mark the New Hole

Use the marking on the combination square to mark new holes closer to the front of the bookcases. 

using a combination square to mark new holes for door hardware
marking new holes to drill for door hinges on shelves
new holes marked for drilling to hang shelf doors

Step 18 – Mark the Hole Depth on a Drill Bit and Drill a New Hole

Place your drill bit inside of an existing bookcase hole.

Use tape to mark where the hole stops so you know how far to drill the new holes.

Drill into where you marked for the new holes to that depth. 

using tape on a drill bit to mark hole depth

Step 19 – Attach Hinges and Door Hardware

Screw the door hardware into the new holes you drilled, and attach hinges to the doors. 

door hardware added to bookcases to hang Oxberg doors
hinges screws to Oxberg doors for hanging to shelves

Step 20 – Hang Doors and Add Knobs

Hang the Oxberg doors to the bookcases, and check to make sure all doors on the built in unit align properly. Then add pulls or knobs. 

Oxberg doors hung to IKEA Billy bookcase built in bookshelves

Style the Shelves

Have fun filling up those bookcase shelves! I like to alternate stacking books and lining up books with decor mingled in.

Play around with heights and shapes until you’re happy with the decor placement. 

Related: Tips for decorating shelves 

finished IKEA Billy bookcase hack for built in bookshelves in an office
shelf decor in a home office with glass front doors

That’s it! There’s one more IKEA Billy bookcase hack in the books!

I didn’t originally intend on using these skinny shelves, but in the end, it definitely worked out!

The entire piece is even more study than the wide version and can hold more books on the shelves because they have more support.

home office with IKEA Billy bookcase hack built in bookshelves for storage

You can see the fully finished home office here with all of the paint colors and decor/furniture sources we used! 

More IKEA Hack Ideas

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5 from 1 vote

DIY Built In Bookshelves Using the IKEA Billy Bookcase Hack

How to make DIY built in bookshelves with glass front Oxberg doors for concealed storage using the budget-friendly IKEA Billy bookcase hack for a high end look on a budget.
Prep Time1 hour
Active Time3 days
Total Time3 days 1 hour
Yield: 1 Built In Bookcase Wall
Author: Lauren
Cost: $1,300.00

Equipment

  • 1 Circular saw or table saw
  • 1 Coping saw or jigsaw
  • 2 Saw horses
  • 1 Power drill
  • 1 Set of drill bits
  • 1 Orbital sander
  • 1 Pack of medium/fine grid sanding pads
  • 1 Cordless brad nailer gun
  • 1 Hammer with claw
  • 1 Pry bar
  • 1 Tape measure
  • 1 Step ladder
  • 4 Clamps
  • 1 Combination square
  • 1 Utility knife
  • 1 Shop Vac

Materials

  • 8 Billy Bookcases size 15 3/4″ x 93 1/4″
  • 4 Oxberg doors long glass/panel style
  • 4 Oxberg doors short glass front style
  • 1 box wood screws size #8 1 1/2"
  • 5 boards 2x4x8 studs
  • 2 boards pre-primed 1x10x8
  • 4 boards pre-primed 1x4x8
  • 1 box finishing nails
  • 2 canisters white latex caulk
  • 1 tube wood filler
  • 1 can Loctite foam for gaps
  • 1 roll Frog tape
  • 1 quart satin finish interior paint matched to IKEA shelves
  • 1 2" angled paint brush
  • 1 foam paint roller – mini size
  • 1 paint tray
  • 1 pencil
  • 8 cabinet knobs or pulls

Instructions

Remove Baseboard

  • To get the Billy bookcases as flush as possible to the back wall, remove the baseboard. Use a utility knife to cut along the caulk lines of the baseboard. Then, use a claw back hammer and a small pry bar to pull the baseboard away from the wall.

Assemble Bookcases

  • Assemble all of the boxes of the Billy bookcases, including the top extension. Leave the bookcases without the thin backing that comes with them since the back wall will become the bookcase backing since you’re building them in.
    You can keep the top extension off until after you anchor the bookcases to the wall.
    assembling IKEA billy bookcases

Correct Gap

  • Since the bookcases are designed to have a backing (but it’s best not to have one in a built-in to allow access to outlets), there will be a small bap at the back.
    To make this look seamless, measure the bookcase and cut a piece of 1×2 board. Attach the 1×2 to the back of the bottom of the bookcase with the finish nailer.
    And the gap is gone! Caulk will fill any cracks later.

Anchor Shelves

  • Measure your wall and make sure the bookcases are centered and place where you want them. Anchor the middle bookcase.

Attach Each Billy Bookcase Together

  • Use your clamps to tightly hold together the sides of two bookcases. Then, screw the wood screws through both sides of the bookcases to secure them to each other.

Build In the Gaps

  • See that little bit of space around the sides and top of the Billy bookcases? We want to fill that in to make the bookcases look like built ins.

Attach 2x4s

  • In the small gaps, drill 2x4s to the wall and the side of the Billy bookcases. Do the same for the top of the shelving unit too.

Attach 1×4 Boards to Face

  • To make the bottom of the bookcases look like one solid built-in piece of cabinetry, attach 1×4 pre-primed boards with finishing nails.
    Use a coping saw or jigsaw to cut out the sides of the boards to mimic the shape of the baseboard on the wall. It doesn’t have to be perfect as caulk can later fix imperfect cuts. Repeat the process for the top of the Billy bookcases, coping the sides of the 1×4 boards to fit the crown molding.
    attach 1x4 boards to base of billy bookcases with brad nailer

Cut 1×10 Boards to Fit Sides

  • Since the sides of the bookcases typically aren’t the exact width of a board, measure the gap between the bookcase and the wall and cut down the 1×10 board to fit as the face on the sides using a circular saw or table saw.

Attach 1×2 Boards to Front

  • Use the finish nailer again to attach 1×2 boards to the fronts of the bookcases to hide the cracks where the bookcases meet together.

Fill Gaps, Cracks, and Nail Holes

  • Use Loctite foam to fill any larger gaps. We used it to fill the small gap between the bottom 1×4 and the bottom of the bookcases since it was slightly too big for caulk. Once dry, cut the foam and sand it smooth.
    Use caulk to fill any cracks between the wall and boards.
    Then, use wood filler to cover any nail holes or cracks in the boards where they meet. Let dry.

Sand Smooth

  • Once all of the fillers are dry, use an orbital sander to smooth it out.

Remove Dust

  • Use a shop vac to remove any sanding dust from the built ins to make it ready for paint.

Paint Boards

  • Paint all of the visible boards with the satin paint you had matched to the bookcases to make everything look like one solid piece of built in bookshelves. You don’t have to paint the Billy bookcases themselves, just the boards so they’ll match them.

Add Doors (optional)

  • Add glass/panel Oxberg doors to the front of a few of the bookcases to provide some concealed storage. Oxberg doors are designed by IKEA to fit Billy bookcases, but by making these built in, there’s a trick to hang them properly.

Mark on a Combination Square for 1×2 Depth

  • Since the existing holes on the Billy bookcases are no longer useful for hanging Oxberg doors as they are intended in design, you have to make new holes to account for the depth of the 1×2 boards added to the front of the bookcases.
    Place a combination square against the 1×2 and mark its depth with painters tape.

Mark the New Hole

  • Use the marking on the combination square to mark new holes closer to the front of the bookcases.

Mark the Hole Depth on a Drill Bit and Drill a New Hole

  • Place your drill bit inside of an existing bookcase hole. Use tape to mark where the hole stops so you know how far to drill the new holes.
    Drill into where you marked for the new holes to that depth.

Attach Hinges and Door Hardware

  • Screw the door hardware into the new holes you drilled, and attach hinges to the doors.

Hang Doors and Add Knobs

  • Hang the Oxberg doors to the bookcases, and check to make sure all doors on the built in unit align properly. Then add pulls or knobs.
    attaching hinges and hardware to doors to hang on bookcase

Have you made your own DIY built in bookshelves before? Or done any other awesome IKEA hack?

If you haven’t, here’s fair warning that you’ll be hooked once you finish your first one. It really is like the best beginner carpentry project with training wheels.

Most Frequently Asked Questions

Is IKEA discontinuing the BILLY bookcase?

IKEA is launching a new BILLY bookcase design in early 2024. The new design will replace the veneer on the old version with a paper foil that will allow more decorative finish possibilities, more durability, and more scratch-resistance.

What is the alternative to BILLY bookcases at IKEA?

Target’s Room Essentials brand of the 5 shelf bookcase is comparable to the IKEA BILLY bookcase, though it’s measurements are slightly different.

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21 Comments

  1. I love it and am trying this right now. I’m attaching the 2×4 to the bookcase side and drywall which is tricky. Did you drill the 2×4 straight into the wall, did you use anchors or did you attach it to a stud? I’m not at a stud and am hoping it’ll be ok with anchors or no anchors.

    1. Hey!! Yes, we anchored the center into the walls, use anchors if not on stud. We also had side frames that we used to attach them too, but if it fits direct beside the walls then place/anchor to the wall.

  2. 5 stars
    I am super nervous about the larger gap at the top – the space too big for caulk – and the application of the foam to fill the gap.

    I have never used Loctite before but have used Great Stuff and that’s a literal nightmare if it gets anywhere you don’t want it.

    Any additional tips on ensuring a good application of the foam filler? I have this gap and need to fill it but am SUPER nervous.

    1. Oh I can see being nervous. I don’t have any tips to share. Your local hardware store specialists may have something ups to talk you through being more comfortable with the process.

  3. Re: using the Loctite Foam for the gap on the lowest shelves – How well is that holding up? Is it durable enough if the shelf is used regularly (books/games being used and put back)?

    Love your project! The finished room is beautiful!!

    1. Hi! This is for a friend’s home. We have only heard feedback that it is still holding up great! They homeschool and use the office daily so I can only imagine it has a lot of use. I will try to reach out at the new year for an update of certain review.

  4. Love how it turned out. One question though. Is there not a big space from back of door to shelf since no 1x were added to front of shelf?

    Scott