ᐅ Why does the color of older Billy bookcases change over time?

Hello everyone, I have a question that has been on my mind for a while, and I hope to get a well-informed answer here: Why does the color of older Billy shelves from IKEA change over time?

I have noticed that especially the white Billy models develop a yellowish or slightly brownish tint after several years, even when they are kept indoors and not exposed to direct sunlight. You often hear about fading in furniture, but in this case, it seems more like a discoloration towards darkening.

Could this be caused by UV radiation, or is it due to chemical reactions in the materials such as particleboard or the surface finish? Or do humidity and indoor climate play a role? I also know that MDF and particleboard coatings can potentially react.

Does anyone have technical explanations or practical experience as to why this color change occurs with the Billy shelves? Thanks in advance for the detailed answers!

Hello Renkin64,

The color change in older Billy shelves is mainly related to the material composition, surface sealing, and environmental influences. I will explain this step by step:

1. Material base: Billy shelves are made of particleboard or MDF panels with a melamine resin or laminate coating. These coatings are not completely UV-resistant.

2. UV exposure: Even if the shelves are not placed directly in sunlight, UV rays penetrate through windows. UV light causes polymer degradation and oxidation of the surface, which leads to yellowing and discoloration.

3. Oxidation: In addition to UV, oxygen in the room causes a chemical reaction with substances in the coating. This process is usually slow but becomes noticeable after several years.

4. Heat and humidity: Fluctuations in temperature and moisture promote microstructural changes, which can result in shadowing and shifts in color.

5. Contaminants such as cigarette smoke or dust film also contribute to a slight browning effect.

In short, it is a combined effect of UV radiation, chemical aging, and environmental factors that slowly yellow the melamine surface.

If you want to restore the shelf, I recommend surface cleaners with a mild abrasive plus an appropriate protective coating.

One question: Is your Billy shelf placed close to a window with a lot of natural light or are there heating sources nearby? This information would help refine the analysis.

The color change is mainly caused by exposure to UV light and oxidation. Indoor air also affects the surface, causing the material to yellow over time.

kulau schrieb:
It is a combined effect of UV radiation, chemical aging, and environmental influences

I agree with this and would like to add that formaldehyde and other volatile organic compounds contained in the particle boards can react with oxygen in the air over time. This oxidative process not only causes yellowing but can also slightly alter the material itself, changing the reflective properties of the surface.

Additionally, the coatings or films used often lack UV protection, which can accelerate the problem. I once reported a test on my website showing that inexpensive melamine coatings yellow significantly more after 5 years than more expensive versions with UV additives.

If appearance is important to you, repainting with light-stable coatings could be considered, although this requires some effort.

I am familiar with this issue because I also have an old Billy bookshelf at home that looks darker and yellowed, especially in the lower sections.

Renkin64 schrieb:
Specifically, the white Billy models develop a slight brownish tint, even though they are only kept indoors

I have noticed that shelves placed in darker corners or areas with poor ventilation tend to discolor more. I suspect that in addition to UV exposure, poor air circulation and possibly even dust accumulation affect the surface.

It also makes a difference how often the surface is cleaned. Dust and deposits can promote chemical reactions or at least refract light differently, leading to a darker appearance.

I think it’s worth observing this closely. Does anyone know if this problem has been reduced in newer Billy shelves due to improved materials?

lisbi schrieb:
…oxidative process not only causes yellowing but can also slightly alter the material itself

Absolutely correct.

Layla schrieb:
…whether the issue with newer Billy shelves has been reduced by improved materials?

This can only be answered to some extent. IKEA occasionally optimizes the surface finishes but mostly relies on proven, cost-effective particleboard with melamine coating. There are slight improvements in UV protection, but no fundamental change in the material.

UV protectors are often found in specialized coatings, which inexpensive mass-produced furniture does not always include to keep costs down.

A practical alternative is to apply UV-protective film to your own Billy shelf or use a clear UV-protective varnish.

One more question: How severe is the discoloration on the shelves? Is the surface still intact, or are there signs of wear or small cracks?