How to Make a DIY Wall-to-Wall Bookcase (An IKEA Billy Bookcase Built in)

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Intro by Robin
Steps by Ed

A small basement bedroom is tricky.  When that bedroom is in an equally small basement that needs to function for a lot of things - it requires some creativity and mad DIY skillz.   

Enter our Basement Guest Room-Library with wall to wall bookshelves.  I've dreamed of having built-in bookcases my whole life! (Is that a normal dream?)

Now, of course, if we didn't want to make our guest room beautiful as well as functional, we could have just pushed some premade bookshelves up against the wall and called it a day.

But, as you may know, that just isn't our style.  We demand function AND beauty.  PLUS we love the challenge of creating rooms on a budget.  That's what all our DIYs are about.  (Have you seen the closet we turned into a basement bathroom? We're still gaga for it.)

This basement guest room needs to work really hard for us:
  • It must make our guests feel comfortable and loved.
  • It needs to hold the bulk of our book collection (our house isn't huge and we LOVE books)
  • It also must have hidden storage for less than beautiful things (I'm thinking bedding, gift wrap storage and files.)
  • And it needs to look great. (And it does! Despite what my beginner photography skills show...sigh.)

And yet another problem to solve...

This IKEA Billy Bookcase Built-in is a problem solver.  Like most basements, ours has small windows. The one in the guest room is weird and it isn't centred.  This made me bonkers! (Though we figured out a clever way to make it look bigger!)

The only comfortable spot for the bed was under this window.  With the window off to one side - the bed wasn't centred.  (It made me twitchy just looking at it.)

That's one of the reasons this bookcase built-in was so perfect down here.  By building it along the left wall it took up enough of the visual space to make the weird window look a bit more centred.  Win!

Another reason this built-in bookcase was a win is the character and personality that it adds.  You know from the other built-ins we've made that we are Co-Presidents of the Built-ins Fan Club.  Seriously, built-ins are amazing small space solutions - and they aren't as hard to build as you may fear.

Last fall IKEA had the sale I was waiting for: 30% off all their Billy bookcases and matching Oxberg doors.  The bookcases are already pretty affordable, especially in white.  The Oxberg doors were more costly - a pair of the doors cost as much as the whole bookshelf!  But I knew that we needed the doors for the hidden storage they'd give us.

So I added it all to my cart and paid to have them shipped.  That was a tough extra cost to pay - but these Billy bookcases are dang heavy!  And we didn't think we could fit 3 Billy's plus 6 doors in our Rav4.  There are times that delivery is worth splurging for.

Without further ado, here's how to make a wall-to-wall bookcase with our IKEA Billy Bookcase Built-in tutorial.  (And we added bookcase lighting to them too, so pretty!)

billy bookcase built in

How to Make a DIY Wall-to-Wall Bookcase (An IKEA Billy Bookcase Built-in)

What you need:

  • As many flat-pack bookcases as will fill your wall.  
    • IKEA Billy's are great - but it's not the only option, you can find similar bookcases at 
    • Amazon (like this one), 
    • Lowes (like this one) and 
    • Home Depot (like this one) for example.  Comparison shop!
  • Bookcase doors - we used Oxbergs
  • 2x4s
  • sandpaper and sander (we use this random orbital one)
  • clamps 
  • screws
  • paint - We found Behr's "White" in eggshell matched the IKEA finish really well.
  • MDF trim, casing and crown moulding, as needed

Optional: How to Add Faux Brick to the Back of a Built-in Bookcase
This is totally optional - gilding the lily really - but we love the look.  You can find how we did this interesting step in the tutorial here.

Optional: How to Add Bookcase Lighting to Any Bookshelf (without hiring an electrician)

We added these super affordable picture lights from Home Depot to our bookcase (Amazon has them, too).  Rather than create one post with 4000 photos, we broke it down.

Here's the tutorial - we include 4 ways to add lighting - and 3 of them don't require ANY electrical skills!

If video tutorials are more your style - just press play here:

How to make a Billy Bookcase Built-in:

Step 1: Assemble the BILLY bookcases. 

ikea billy bookcase

  • So, you may wonder, why the heck did we install these upside-down?!?  
    • A fair question.  This room is not tall - about 6.5 ft.  But we knew we wanted to add library lights to the top of each shelf.  
    • By installing them upside down we had room for lights and crown moulding!  
    • The uniform nature of the BILLY meant that we could do this - have the doors still fit on the bottom half.

Step 2: Decide on the spacing

ikea built in bookcase

  • The easy one to decide on was the centre bookshelf - we centred it. Then we played around with spacing the other two shelves until it felt right.
  • We ended up using 2x4 stock as the gap between units to make them look a little more substantial.  We set them back by about 3/8".  (And 2x4's are super cheap!  They just need sanding like crazy.)

Step 3: Clamp and Commit

how to make a billy bookcase built in

  • This means screwing into the bookcase units and mounting to the wall. 
  • IKEA provides brackets to attach to studs to prevent tipping over: use them. Even though you'll be putting lots of framing around it, the brackets will help hold things in place, and keep them square, while you build everything else.

anchor billy bookcases securely for built in
IKEA provides lots of these brackets - we used them to connect to not only studs but joists and anything else we could find.

clamp billy bookcases for built in
Clamps are your friend. Once you have the BILLY units assembled, connected to each other and secured to the wall, they can be removed.

Step 4: Screw the bookcases to each other

secure billy bookcases together
When joining the bookcases together, try to hide the screws whenever possible in places you won't see. 

These ones will be hidden by the crown moulding

billy bookcase built in hinges for doors

And if you have doors, the hinges can be used to hide screws too.

Locate where the hinges will land and then use one of the predrilled holes that will be behind the hinge.

billy bookcase doors
Tadaa! Hidden screw. 

You can attach the doors at this point too (if you're adding them). We had to move up the hinge mounts a tiny bit to make the door tops level with the middle shelf. This was really just an aesthetic issue - not a functional one.

Step 5 - Fill in next to the walls


We made a choice to have a larger space between the sides of the bookcases and the wall.

This looked better than 4 exactly even gaps.

Side Question: Does anyone else begin styling their projects for 'After' photos while they are still in the middle of construction? Asking for a friend...

frame for billy bookcase built in

We built small frames and then attached some primed MDF casing to hide the gaps and make the whole unit look like one complete piece.

Give yourself lots of room to nail into. Primed MDF will give a nice, finished look - consistent with the rest of the BILLY unit - but they are not very rigid and need support.

trim for billy bookcase built in
The MDF may need some trimming and sanding to fit in next to the wall. (Unless by some miracle your walls are perfectly square.)  Keep trying it in place till it works. 

Step 6: Crown Mould and remaining finish trim 

crown moulding billy bookcase built in

We added bookcase lighting (tutorial is here), but the rest of the trim would be similar - only MUCH EASIER for you if you didn't incorporate lights. 

First, over where the kick plates would be, we added a thin piece of pre-finished MDF panel. 

Then we added crown moulding at the ceiling. 

billy bookcase built in crown moulding
Last, we cut another strip of 3/8, thicker MDF to make up the remaining gap.

Step 7: Fill and Sand, Caulk and Paint

trim and paint billy bookcase built in
You can hide all kinds of messes with painted projects!  
Fill those gaps with caulk and holes with wood fill.  Sand it smooth and paint!

And then you're done!

built in billy bookcases with doors

We are bookworms, so filling these shelves with books was easy.  And we all love the look of a well-loved library.

You might have noticed that we didn't put any hardware on the doors - that's intentional - though we may change our minds when the final room comes together.  We left it without pulls because the room is tight and we wanted to keep the area beside the bed as open as possible.  This way our guests aren't snagging their jammies on any knobs when walking by the shelves to climb into bed.

ikea hack billy bookcase built in

This is one of dozens of projects we've created in our Budget Basement Makeover (more here) and one of many projects in our cozy Guest Room-Library (more here).  

Other projects in our Basement Guest Room-Library:

  • Green Vertical Shiplap Panelled Wall treatment - which cost us almost nothing 

Wait until you see it all!  Keep in touch and follow our progress by subscribing at the top of this page.


  1. Beautiful job. I love IKEA hacks. Hoping to do something like this for a dinning room - no more hutch with limited storage. I dream of a whole wall of these cabinets - what ever will fit well, with glass doors on top for my dishes, and doors on the bottom for storage of linens, etc. (Or a drawer for silverware, etc., and then doors.) I assume I might have to make the shelves very sturdy, but I think I would look great, and my husband is great at figuring this kind of stuff out. (Now I would just have to convince him!)

    1. Thank-you!!
      Go for it, Joanyzz! Your plan sounds fabulous - having lots of storage makes keeping things tidy soooo much easier too. Hope your husband says yes! :)

  2. I have wanted to do this for years and now I have the directions! Fantastic job! I love the lights!

    1. I hope you do, Giselle! It’s such a great project and so much less difficult and costly than it looks. Thanks for your comment! 😊

  3. I am so glad I found your post, this is exactly what I am building and this gave me help on some of the steps. Thank you!

    1. That’s so cool, Aaron!!! Glad this is helpful for you and thanks so much for letting us know! 🙌

  4. I really like all of your projects. For this one I would probably use wood boards for the shelves as MDF has a tendency to bow from the weight of books (and anything else!). I would also slide the shelves forward until they're flush with the front of the bookcase to allow the cabinet doors to close straight without leaning inward against the edge of the inner shelf.


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