She has arrived!

I have been wanting to do the Ikea Billy Bookcase built-in hack for so long in our kids’ playroom.  But we did have shelving and all was okay enough to not spend the $1,000 … until it wasn’t.  The playroom is always a disaster zone.  

My wife, former professional organizer, finally said – order them!  And I ran!

Build level: beginner – intermediate (depending how many and how level your home is!)

My initial plan was to purchase 5 of the bookcases + the extension units so that it would be floor to ceiling.  Well, after measuring (always measure twice!), our space was ½” too short to use five.  So, I had to rework the plan and that’s where the spacers came in.

There are many options for how you can space them – I know a lot of people will basically butt the bookcases together and then use a 1×2 to cover where they connect.  I’ve seen beautiful results using a 1×4 between the units.  For us, we had roughly 31” leftover to space out.  I LOVE how it turned out, but in hindsight, I think I would have used 1x4s vs the 1×6 so that I had more room on either side since I turned that into storage.

Tools (some of my favs listed here):

  • Miter saw
  • Drill
  • Brad nailer
  • Pin nailer
  • Screw driver
  • Level
  • Clamps

Materials (several listed on this link):

  • 4 Billy Bookcases
  • 4 extension units
  • 8 Oxberg doors
  • 10 knobs
  • 3 – 1x4x8 MDF
  • 3 – 1x6x8 MDF
  • 2 – 1x8x8 MDF (my side storage – not required)
  • 4 – 1x2x8MDF
  • 2 – 1x8x8 lattice moulding for the bottom
  • Spackle
  • Wood filler
  • Caulk 
  • Zinsser Primer


Step 1 – Measure:

Measure twice.  How wide is your wall and how high are your ceilings?  The Billy units with the extension gives you an overall height of 93 ¼” so it’s easy with 8’ ceilings.  The width of the ones that I used are 31 ½” (they have skinny ones half the size as well). If your ceilings are higher, you will need to build a platform for them to sit on and then your top trim will be thicker.

Step 2 – Plan:

Plan out your space.  Time for some math.  I took the overall width of my space and then subtracted the width of all 4 units together.  Now I knew how much extra I had to work with for trimming it out.  I did a very rough sketch of how I wanted things spaced out and ultimately decided to use 1x6s between the units leaving me with roughly 9 ¼ – ½” on either side.  Since that was a decent amount, I decided to try to create some hidden shelving in there for extra storage … my track record with doors was shaky as things really have to line up but I figured I could always seal it off if it didn’t work!

I initially was going to build a platform for the units to sit on but decided to put them straight on the floor so that my bottom and top trim were the same size.

Also note where outlets are in your space – do you want access to them?  We have two outlets on the wall there and so we brought them through the units so we’d be able to have a hidden charging space for toys.

Step 3 – Remove baseboards:

Use a box cutter to score the caulk on top of the baseboard and use a trim prybar and hammer to pull it out of the wall.  Since we want the units flush, we need the area clear.

Step 4 – Assemble:

Assemble.  The units are very easy to assemble.  It took me less than 15 minutes per unit.  Now I could line them up to see how things were going to look.  You also can tell if your floors aren’t level or your walls are bowed with them all lined up … our house is from the 80s and things were not level … this is where some shims will come in handy!  Do not install the extension units yet – that will come after all units are anchored.

If you’re building a platform – do that now!

Step 5 – Secure:

You’re going to want to anchor these into walls.  Since our walls were bowed and floors weren’t fully level, I initially anchored one side on the bottom and then the top.  Once there was one that was fully level, I started on the unit next to it and adjusted based on the first level unit.  I cut several scraps of wood to use as spacers between each unit so that when I was lining them up to anchor, the spacing would be exact for the 1x6s I was putting on top.  Several clamps will come in handy!

Make sure you keep checking that each individual unit is level as well as that the units next to each other are level.  This took some shimmying here since things weren’t level to start.

*if you’re going to keep your outlets, use the toothpaste trick!  Put a little bit of colored toothpaste around the perimeter of the outlet (not in the socket!) and then press the back of the unit against it and now you know where to cut!

Step 6 – Trim it out:

If you are going wall to wall with the units and your units do not go all the way to each wall, you’re going to need to place a vertical piece of wood on each wall to anchor the base and top trim to.

Now that all units are anchored into the wall, we can install the extension units on top.  Now we can check the height of the top trim – the 1×4 was a perfect fit – it would sit on top of the 1x6s that were going in vertically.  Before we can install the trop tim, we need to put in the bottom trim and then secure the panels going between the units.

In my design, I had the vertical panels resting on top of the base trim, so I measured out what I wanted to use there – a 1×4 was a perfect fit and I secured that into the base.

  • Since our walls were about 13’ wide, I had to connect two 1x4s – I beveled each piece at 45 degrees so that they would slide into each other and make it look like one piece.

Then I had to measure the height of each of the 1x6s.  They had to fit perfectly from the top-bottom trim.  Once cut, using wood glue and a pin nailer, you can secure the vertical pieces directly into the bookcase. *don’t worry if it’s not perfect as wood filler and paint fix imperfections! 

Now that our panels are in, we can secure the top trim.  

Finishing the sides will look different for everyone.  Since I wanted to create extra little storage, I then had to build out a door.  Otherwise, you can just secure a panel in to close it off.

Step 7 – Spackle, Caulk, Paint:

At this point, I figure out where I wanted the shelves to go so I placed the hardware in the holes so that I didn’t cover them up.  Then I used spackle on the rest of the holes so they wouldn’t be visible anymore to give it a higher end look.  

Time to caulk – I caulked around any place where boards met – as well as the top of the ceiling and side pieces on the wall.  (make sure you use paintable caulk and keep wipes handy to help spread it out)

Once dry, sand down where you spackled and wipe clean.

Time to paint.  I used the Zinsser BIN primer as I heard it was best on Ikea units.  It has a watery consistency and not the best smell (shellac).  I primed the doors as well as I hadn’t installed them yet.

Once dry, it was time to paint.  This space is right next to our kitchen which is very white, so I wanted to have a little color.  I let my wife decide from 4 swatches and she chose Sherwinn-Williams Sea Salt.  The room doesn’t get a ton of natural light so it added a soft brightness to the room.  And the color goes soooo well with gold hardware, so I was easily able to convince her of that (she prefers nickel).  

The Emerald SW paint required two coats (and a few touch ups) so this was the most time consuming part as it requires 24 hours to cure.

Step 8 – Doors:

The doors … not the most fun project since they had to ALL be level with each other as well as have a good spacing between them.  The hinges they come with are adjustable but it requires a lot of trial and error.  Especially because I couldn’t just screw the hinge into the already drilled holes since I trimmed out the base and then right above where the door was going.

Step 9 – Hardware:

To make life easier, I just put the knobs on the pre-drilled door holes.  This way, it was already lined up perfectly and were lower so my kids could easily access.

To add some more light and a visual at the top, I added these battery operated picture lights using 3M Command Strips – the velcro kind – so I can easily take them down to charge and if I wanted to switch them up, it won’t ruin my trim.  One remote will work all of them!

The added step for me was the side doors and eventually will add shelving inside for extras!  Overall, I am in love and so happy with how this turned out.  And now I have another space to decorate for all the holidays + season

Let me know if you try this!