Blog · 6 October 2026
BILLY bookcase: fixing it to the wall and using extension units
The BILLY is quick to put together, but a wall of bookcases that stands straight and safe needs a little more care.
A BILLY bookcase is 202 cm tall and must always be fixed to the wall to prevent it from tipping over. With a 35 cm extension unit it reaches 237 cm, so the bookcase goes almost up to the ceiling. If you place several bookcases side by side, connect them to each other and level them together. Measure beforehand whether the total height fits under your ceiling.
Always fix it in place
A full bookcase is heavy and narrow. If a child pulls on a shelf, or the bookcase stands on carpet, it can tip forward. That is why IKEA supplies a tip-over restraint. The screws and wall plugs for your wall are not included, as they differ depending on the wall type.
You can read more about this in our article on fixing cabinets to the wall.
Working with an extension unit
The extension unit goes on top of the bookcase and is fixed to it. This makes the bookcase 237 cm tall. With a 240 cm ceiling that only just fits, and you cannot build the bookcase lying down and tip it upright. Position the bookcase first, then add the extension unit.
Several bookcases side by side
- Start in a corner or at the highest point of the floor.
- Level the first bookcase precisely, and the rest will follow that line.
- Connect the bookcases to each other through the side panels.
- Fix each bookcase to the wall separately.
- Fit the doors only once all the bookcases are standing, so you can adjust them all in one go.
Have it assembled
A whole wall of BILLY bookcases, extension units and doors is a job of a few hours. On the BILLY assembly page you can see what we do for you.
Frequently asked questions
Frequently asked questions
Does a BILLY bookcase need to be fixed to the wall?
Yes. IKEA requires the bookcase to be fixed to the wall using the tip-over restraint supplied.
How tall is a BILLY with an extension unit?
The bookcase is 202 cm tall and the extension unit is 35 cm. Together they reach 237 cm.
Can you assemble a complete wall of bookcases?
Yes, including extension units, doors and wall fixings. Send your order list for a fixed price upfront, from €79.
Want it assembled?
Fixed price upfront, pay after assembly
Upload your order list or a screenshot of your shopping basket and you will receive a clear price by email. No call-out fees, no start-up fee.
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Upload your order list or describe what you need assembled. You will receive a clear price by email.
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How it works
- Send your order list or a screenshot
- You receive a fixed price by email
- We assemble, you pay afterwards