ᐅ Why do screws in BILLY shelves come loose even after repeated tightening?

Hello everyone, I have a problem with my Billy shelves that really puzzles me: Why do the screws in BILLY shelves keep loosening over time, even when I tighten them multiple times? I have already fully assembled the shelf, tightened the screws firmly, and then checked them again – yet at least one screw loosens again with every use or movement.

I understand that these are made of wood-based materials and that screws sometimes need to grip into them, but I think there is more to it than just material fatigue. Could it be related to the design or perhaps the type of screws used? Are there better assembly methods or specific types of screws that can reduce this issue in such shelves? I look forward to well-informed experiences and tips on how to make my shelf permanently stable.

The problem often comes from the material – chipboard and softwood may not hold screws securely. It is best to reinforce with larger dowels or metal connectors.

The repeated loosening of screws in BILLY shelves is often due to the combination of the material and mechanical stress. The particleboard used for the back panels has low density and provides little grip for the screw threads.

Additionally, movements of the shelf or slight shear forces during use create tensile stresses on the screw threads, which promote loosening. In practice, even tightening the screws multiple times only provides a short-term fix.

As a solution, self-locking screws (e.g., with plastic inserts) can be used, or additional wood glue can be applied in the pilot holes. Alternatively, metal brackets can be installed to relieve the tension on the screws.

For truly long-lasting stability, the direction of the load and the mounting location within the shelf should be considered, screws sized accordingly, and suitable joining techniques employed if necessary.

draleo schrieb:
The chipboard provides little grip for the screw threads.

Exactly, that’s typical for engineered wood products. I once tried assembling my BILLY shelves using just standard wood screws, but they kept loosening even though I thought I had tightened everything enough. 🙃

My tip for DIY projects: applying a tiny bit of thread locker (a product that doesn’t harden completely but helps prevent loosening due to vibrations) works wonders here. I also often use small metal brackets if the shelf needs to hold more than just books. Those are really affordable and save a lot of hassle. 🙂

sobau schrieb:
The problem often comes from the material – particleboard and softwood do not hold screws optimally.

Thanks for the tip.

I also suspect that the material has chipboard characteristics, but I’m still surprised that even the back panel joints repeatedly loosen over time – although there is hardly any mechanical stress in that area. This leads me to believe there might be a design issue; perhaps the screws are not properly sized or the assembly method puts unnecessary stress on the shelving unit.

draleo schrieb:
One solution would be self-locking screws (e.g., with plastic inserts) or the use of additional wood glue in the drill holes.

Applying glue inside the screw holes sounds interesting; I haven’t tried that yet, but it could be an option. Has anyone here tested this successfully?

jassimba schrieb:
Has anyone here successfully tested this?

I wouldn’t just experiment with any kind of glue. In my opinion, the real issue is that IKEA designed this to be inexpensive and suitable for mass production – meaning it prioritizes quick assembly over long-term durability.

Screws loosen whenever the design, materials, and load don’t properly match. So this is not a flaw on jassimba’s part, but a design challenge.

Pro tip from me: If you want it truly stable, get metal or corner brackets from the hardware store, or use alternative screws with factory locking mechanisms. Otherwise, the BILLY shelving system is simply not intended for heavy, permanent loads – it’s more for light storage and occasional use.