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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 hr
Active Time3 d
Total Time3 d 1 hr
Yield: 1 Built In Bookcase Wall
Author: Lauren
Cost: $1,300.00


  • 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


  • 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


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