ᐅ Why do screws come loose in BILLY units despite correct installation?

Hello everyone,

I have a recurring issue with my BILLY shelf from IKEA: despite correct assembly, the screws loosen in several places. I assembled the shelf exactly according to the instructions, tightened all screws with the recommended torque, and even checked that nothing was loose. Still, after a few weeks, I noticed that some screws had come loose or even worked completely out.

My question is: Why can screws loosen on BILLY shelves despite seemingly correct assembly? Could it be due to the quality of the screws, the material properties of the particleboard, vibrations from use, or are there known design weaknesses?

I would appreciate any tips or explanations if you have had similar experiences or technical knowledge on this subject.

This often happens due to wood moisture and internal stresses in the material.

With chipboard, the screws may loosen slightly because of material tension. You might want to replace the screws with fine-thread ones.

Multiple small torque cycles can also help: tighten several times, loosen, then tighten again.

Ritaba schrieb:
This often happens due to the wood’s moisture content and internal stresses in the material.

Exactly, chipboard sometimes doesn’t behave the way we want – a little movement caused by changes in moisture content is quite normal. 😉

I suspect that the loosening of the screws is also caused by micro-movements in the shelving unit when it’s in use or if the floor is slightly uneven.

The tip about fine-thread screws is great, as they grip the wood better. Alternatively, a small drop of wood glue on the threads might help; it holds firmly without having to dismantle the entire shelving unit.

Sometimes screws are intentionally installed less tightly to avoid splitting the wood – basically a compromise made by the manufacturers.

Give it a try; often a little adjustment goes a long way, and the screws will stay where they belong. 🙂

Katan schrieb:
Otherwise, maybe a small drop of wood glue on the thread could help. It holds reliably without having to completely dismantle the shelf.

Thanks for this tip, that sounds like a good idea.

I just wanted to add a small note: The screws are the original metal threaded screws, not plastic anchors or anything like that, and the shelf doesn’t carry heavy loads, nor is it installed too close to the wall. Still, the mechanical tension seems to loosen over time even with normal use.

One more question for everyone: Have you ever used threadlocker or screw sealant to prevent loosening, or would that be overkill for typical home use? I want to keep the shelf stable without too invasive an intervention.