I was maybe eight years old the first time I saw a proper home library. My grandmother’s neighbour in Porvoo had an entire wall of books — floor to ceiling, with one of those rolling ladders. I stood in that room and decided right then that I would have one too. Twenty-something years later, living in a 68 m² apartment in Helsinki with plasterboard walls and a rental-friendly mindset, the dream felt very far away.
Then I discovered what three IKEA Billy bookcases, some pine trim, and a weekend of mild swearing could accomplish.
Why the Billy Bookcase Is Perfect for This Hack
I know, I know — everyone and their cousin has done a Billy hack. But here’s the thing: there’s a reason this particular bookcase keeps showing up. The 80 cm wide Billy is exactly 237 cm tall in the floor-to-ceiling version (the BILLY OXBERG). That’s almost the exact ceiling height of most Finnish apartments built after the 1970s. My ceilings are 240 cm, which left me with only a 3 cm gap to fill at the top. That’s nothing. A piece of crown moulding covers it perfectly.
The depth is another win. At 28 cm, it’s deep enough for most books but shallow enough that it doesn’t swallow your room. I measured our living room wall — 260 cm wide — and three 80 cm Billys fit with 10 cm left on each side. That remaining space? Filled with filler strips that make it look like the shelves were built into the wall.
Could I have had custom shelving made? Sure. A carpenter quoted me €2,400. For bookshelves. I nearly dropped my coffee.
The Complete Materials List
Here’s every single thing I bought, and what it cost. I’m including the store because I know someone will ask.
From IKEA (Espoo store):
- 3× BILLY bookcase, 80×28×237 cm, white — €69 each = €207
- 6× Extra shelf inserts — €5 each = €30
From K-Rauta (Konala):
- Pine crown moulding, 260 cm length, 6 cm wide — 2 pieces = €18
- Pine baseboard trim, 260 cm, 4 cm — 1 piece = €7
- Filler strips (pine), 1 cm × 10 cm × 240 cm — 2 pieces = €9
- Wood filler (Tikkurila puukitti), white — €6
- Paintable caulk (akryylimassa) — €5
- Sandpaper, 120 and 220 grit — €4
From Bauhaus (Espoo):
- Tikkurila Helmi 30 furniture paint, white, 0.9L — €28
- Small foam rollers (10 cm), pack of 5 — €8
- Angled brush, 3 cm — €4
- L-brackets for wall anchoring, 8 pieces — €12
- Concrete screws (betonikiinnike), 6×60 mm — €8
Total: €346
Wait — I said under €200, didn’t I? Here’s the thing. The Billy bookcases are stuff most people already have, or can get secondhand. I bought one new and found two on Tori.fi for €15 each. The actual hack — turning basic bookcases into built-in shelving — cost me €139. The paint and trim are where the magic happens.
Tools You’ll Need
Most of these I already had. The drill I borrowed from my neighbour Mikko (thanks, Mikko).
- Drill with hammer function (for concrete walls — more on that nightmare below)
- 6 mm concrete drill bit
- Mitre saw or mitre box with hand saw
- Level (I used a 120 cm one)
- Measuring tape
- Pencil
- Caulk gun
- Painter’s tape
- Drop cloths
If you don’t own a mitre saw, K-Rauta will cut your trim pieces to length for a couple of euros. I’d honestly recommend this if you’ve never used a mitre saw before. The 45-degree corners on crown moulding are not forgiving.
Step 1: Assemble and Prepare the Bookcases
Nothing revolutionary here — follow IKEA’s instructions. But a few things I learned:
Don’t attach the backing nails fully. Just tap them in about halfway. You’ll want to pull the backing off later to paint behind it and to access the wall for anchoring. I hammered mine in completely the first time, then spent 20 minutes prying tiny nails out with a flathead screwdriver. My fingertips were not happy.
Also, if you’re using secondhand Billys, check the shelf pin holes. Some older models have slightly different spacing. Mine matched perfectly, but I’ve heard horror stories.
Step 2: Wall Anchoring (The Finnish Apartment Edition)
Here’s where things got interesting. Our apartment building is from 1982, which means the walls are concrete. Not “maybe there’s a stud behind the plasterboard” concrete — actual poured concrete behind a thin skim coat. Every wall. This is incredibly common in Finnish kerrostalo apartments.
The good news? Concrete is incredibly strong. Once you get a screw in there, that bookcase isn’t going anywhere until the building comes down.
The bad news? Drilling into it feels like you’re performing dentistry on the building itself. The noise is absolutely unholy. I warned my neighbours, brought them chocolate, and drilled during the allowed hours (weekdays 8–20, Saturdays 10–18 in our taloyhtiö).
Here’s my method:
- Position the first Billy against the wall, shimming the base until it’s perfectly level. Our floors slope about 4 mm over the 240 cm span. Typical.
- Mark the wall through the pre-drilled holes at the top of the Billy’s back panel.
- Pull the bookcase away, drill into concrete using the hammer drill setting.
- Insert plugs, push the bookcase back, and drive the concrete screws through.
- Repeat for each bookcase.
I used two L-brackets per bookcase at the top, screwed into both the bookcase and the wall. Belt and suspenders. We get earthquakes here approximately never, but that thing is holding 40+ kg of books per shelf. I’m not taking chances.
Step 3: Join the Bookcases Together
This is what turns three separate pieces of furniture into one cohesive unit. I used short wood screws (3×16 mm) to attach the bookcases to each other through the side panels. Three screws per connection point — top, middle, and bottom. Pre-drill the holes or the particle board will split. Ask me how I know.
Once they’re joined, they feel remarkably solid. You can actually feel the difference when you push against them.
Step 4: Fill the Gaps
This is where the transformation starts to happen. The gap between the bookcases and the side walls (about 10 cm on each side in my case) gets filled with pine filler strips. I cut them to height and nailed them directly to the wall with a couple of finish nails and some construction adhesive.
Then comes the caulk. Run a generous bead along every seam — where the bookcases meet each other, where they meet the filler strips, where the filler strips meet the wall. Smooth it with a wet finger. This single step is what makes the whole thing look built-in rather than “I shoved some bookcases against a wall.” The caulk fills all those tiny imperfect gaps and creates seamless transitions.
I probably used an entire tube of caulk. Maybe more. Don’t be stingy with it.
Step 5: Add Crown Moulding and Baseboard
The crown moulding at the top covers the gap between the bookcase tops and the ceiling. I measured, cut the pieces with 45-degree mitre joints at the corners, and attached them with finish nails and wood glue. The baseboard at the bottom does the same thing, tying the bookcases visually into the room’s existing trim.
Getting those mitre joints tight took me three attempts. My first cuts were slightly off, and even half a degree shows in a 6 cm piece of moulding. If your corners aren’t perfect (mine weren’t), fill the gaps with wood filler, let it dry, and sand smooth. Nobody will ever know.
Step 6: Paint Everything
This is where patience matters more than skill. I used Tikkurila Helmi 30 (semi-matte furniture paint) in white, and here’s my honest painting advice:
Use a foam roller. Not a regular roller, not a brush for the large surfaces — a small, dense foam roller. It gives the smoothest finish on these melamine surfaces. I tried a regular woven roller first and the texture looked terrible. The foam roller laid down thin, even coats that dried almost like spray paint.
Sand lightly between coats with 220-grit sandpaper. Yes, it’s tedious. Yes, it makes a massive difference. Two coats minimum, three if you’re covering a darker colour.
The trim pieces (crown moulding, baseboard, filler strips) need primer first since they’re raw pine. I used the same Helmi paint for everything so the sheen matches perfectly.
Paint the trim and the bookcases separately before final installation if possible. I painted the crown moulding on a drop cloth in the hallway, then attached it after it dried. Much easier than trying to paint overhead while paint drips in your hair. Not that I would know anything about that.
Total painting time: About 6 hours spread over two days, including drying time between coats.
Step 7: The Adjustable Shelf Secret
Here’s a small upgrade that makes a big difference. The stock Billy shelves sit on those little metal pins. They work fine, but they leave visible holes all up and down the sides. I picked up a pack of adhesive-backed shelf pin hole covers from Amazon (€4 for 100 pieces) and covered every unused hole. It takes about 15 minutes and eliminates that “this is clearly an IKEA product” look.
I also spaced my shelves at varying heights — taller sections at the bottom for art books and shorter sections at the top for paperbacks. It looks so much more intentional than uniform spacing.
Styling the Shelves
A full wall of books is gorgeous, but it can also feel like a wall. I break things up with objects placed between groups of books: a small ceramic vase I found at a kirppis in Kallio, a framed photo from our trip to Tallinn, a small trailing pothos plant that’s somehow still alive.
The rule I follow: about 70% books, 20% objects, 10% empty space. That empty space is important. It gives your eye a place to rest. If you fill every square centimetre, it goes from “curated library” to “hoarding situation” pretty fast.
For more ideas on mixing objects and books together, I wrote about the art of blending vintage finds with modern pieces — the same principles apply to shelf styling.
What I’d Do Differently
I’d buy the better caulk. I went with the cheapest akryylimassa and it shrank slightly as it dried, leaving hairline gaps in a few spots. The Soudal brand paintable caulk (about €3 more) is what I’d use next time.
I’d also start the project on a Friday evening, not a Saturday morning. Assembly and wall anchoring on day one, caulk and filler drying overnight, painting on Sunday. I tried to do everything in one Saturday and ended up painting at 10 PM under bad lighting. Don’t be like me.
How This Fits a Small Space
Our living room is not large — about 18 m² — and I was worried the wall of shelving would make it feel smaller. The opposite happened. Because the shelves are white and reach the ceiling, they actually make the ceiling feel taller. The room reads as more intentional, more finished. Before, that wall had a sad KALLAX unit and a random side table. Now it’s the focal point.
If you’re working with a small living room, I have a whole post about maximising space in compact rooms that covers vertical storage solutions like this one.
The Final Cost Breakdown
| Item | Cost |
|---|---|
| 3× BILLY bookcases (1 new + 2 secondhand) | €99 |
| 6× Extra shelves | €30 |
| Crown moulding | €18 |
| Baseboard trim | €7 |
| Filler strips | €9 |
| Wood filler | €6 |
| Caulk | €5 |
| Sandpaper | €4 |
| Paint (Helmi 30) | €28 |
| Foam rollers + brush | €12 |
| Wall anchoring hardware | €20 |
| Shelf pin covers | €4 |
| Total | €242 |
Okay, technically it came in at €242. But if I’d found all three Billys secondhand (they go for €10–20 on Tori.fi constantly), it would’ve been under €200 easily. Close enough. Compared to the €2,400 carpentry quote, I’ll take it.
The whole project took one long weekend. My husband helped with the wall drilling and holding the crown moulding in place, but I did everything else solo. If you’ve assembled IKEA furniture before and you own a drill, you can absolutely do this.
Now if you’ll excuse me, I need to go buy more books. The shelves are looking a little too organised.
For more budget-friendly home improvements, check out my post on doing a kitchen makeover without spending a fortune. Same philosophy — big impact, small budget, and only a moderate amount of swearing.
