ᐅ Converting KALLAX with a Shelf Divider – Any Tips?

Hello forum,

I am considering modifying my IKEA KALLAX shelving unit by adding divider panels and would like to hear your advice. More specifically, I want to subdivide individual compartments of the shelf with dividers to create a more detailed layout and improve stability. I am particularly interested in the following points:

1. Which materials and tools are best suited for installing divider panels into an existing KALLAX shelving unit?
2. Are there specific mounting points to consider, or can the dividers usually be installed freely within the compartment?
3. Do you have experience with custom-made dividers versus ready-made ones (e.g., MDF or plastic)?
4. Are there any pitfalls during installation, for example regarding load-bearing capacity or strength?

I already have some tools at home but am not a professional—so practical advice on the process is very welcome.

Thanks in advance for your help!

Gastone61 schrieb:
I am considering modifying my KALLAX shelf from IKEA with an internal divider.

That sounds like an interesting project! Generally, I recommend measuring the KALLAX compartments very precisely before installing the dividers, as even IKEA sometimes has slight production variations.

Regarding materials: MDF boards are the most common choice because they are easy to work with and provide good stability. An alternative would be acrylic sheets (Plexiglas) if you want a visually lighter look. Both can be fixed inside using small metal brackets or wooden strips.

Important: The shelves of KALLAX are made with thin panels, often around 3/4 cm (about 1/3 inch) thick, so you shouldn’t just loosely place heavier or large dividers inside. It’s best to secure them with small screws through brackets attached to the edges. Screwing directly into the side walls is possible but can sometimes cause splitting—pre-drilling is essential!

Gastone61 schrieb:
Are there any pitfalls during installation, for example regarding load capacity or durability?

Make sure that, especially when adding multiple dividers in entire sections, the load does not become too heavy. Aim to distribute the weight so that individual compartments are not overloaded. Excessive pressure from too much weight can cause the material to bend or warp over time.

One more practical tip: If you don’t have the option to screw in the dividers securely, sturdy wooden or plastic wedges can also help stabilize their position. However, I would consider that only a temporary solution.

How large is the KALLAX you want to modify? And how do you envision the dividers?

Nathanaelk schrieb:
MDF boards are the most common because they are easy to work with and provide good stability

I can confirm that. MDF is also great because you can easily paint or laminate it, in case the new interior design should be a different color than the original KALLAX.

Gastone61 schrieb:
Do I need to consider specific mounting points, or can it usually be installed freely inside the compartment?

In practice, most KALLAX compartments are fitted without designated mounting points. Many attach the dividers using brackets or small wooden slats on the inside edges. It helps to carefully pre-drill the holes in the shelving unit to avoid splintering.

Regarding stability: depending on the size of the divider, I recommend fastening not only at the top edge but also, if possible, at the bottom or in the middle to prevent any wobbling. The KALLAX sides are stable enough, but if you install multiple dividers, the load distribution changes significantly.

One more note: if you are planning major modifications or expect the shelf to carry heavy loads, consider adding external supports or reinforcing the back panel. This greatly improves durability.

What kind of material did you have in mind for the dividers? And what is your intended use—for example, organizing binders, books, or decorations?

Gastone61 schrieb:
Which materials and tools are best suited for installing shelf dividers in an existing KALLAX unit?

MDF boards are ideal. You will need screws, small angle brackets, and a cordless drill.

Gastone61 schrieb:
Do I need to consider special mounting points?

No, you can usually mount freely; just make sure to fit the internal dimensions of the compartment precisely.

Gastone61 schrieb:
Experience with DIY dividers versus ready-made ones?

DIY is more flexible, ready-made is often already sized correctly but usually more expensive.

Gastone61 schrieb:
Are there any common pitfalls during installation?

Pre-drilling is important to avoid cracks. Do not overload the dividers.