ᐅ Screwing KALLAX Units Together – Is It Better Than Just Stacking?

Hello everyone,

I am currently arranging my apartment and using various KALLAX units from IKEA for this. So far, I have simply stacked them on top of each other, which looks quite good, but I am wondering if it might be better to fasten the units together with screws.

My specific question is: Is it better to securely screw KALLAX units together rather than just stacking them? What are the practical and safety-related advantages or disadvantages?

I am mainly thinking about stability, potential load from weight, safety with children, or in case of moving. Are there also any special tips or procedures to consider when connecting the units?

I look forward to your opinions and experiences!

The question of whether KALLAX units are better screwed together or simply stacked can be answered technically as follows: Screwing the units together primarily provides greater stability and prevents them from shifting under load or during transport.

An important aspect is also safety, especially in households with small children. A shifting unit can quickly become a hazard. Additionally, screwing helps distribute the load evenly, so the units carry weight uniformly and do not warp.

However, care should be taken when screwing to avoid damaging the units unintentionally. With KALLAX, stability is also achieved through snap-together connections, but in my opinion, the additional fastening is advisable when the shelves are tall or used in high-load areas.

Hello Gavinotan,

I would like to add that screwing the KALLAX units together not only improves stability but also enhances safety. Many users underestimate how quickly relatively lightweight furniture like this can shift or wobble under excessive load.

It is also important not only to secure the units to each other but also to anchor them to the wall. This helps prevent tipping, which is especially important if there are children around.

If you have no prior experience with furniture assembly by screwing, it is usually sufficient to connect the units with standard wood screws—ideally at the points where the units meet. However, you should choose the material on the inside carefully so that the screws have a good grip and the material does not break.

I also recommend checking the KALLAX units for unevenness on the floor after screwing them together—if needed, small shims can be placed under the feet to ensure better stability.

I can add the following regarding the detailed technical aspects:

KALLAX modules are mostly made of particle board with a thin melamine coating. Therefore, drilling and screwing must be done very carefully to avoid damaging or splitting the material.

It is advisable to drill pilot holes first, about 1-2 mm smaller than the screw diameter, to protect the material. Using screws that are too thick or not pre-drilling can cause the board to crack or swell.

For screwing, I use stainless steel countersunk screws to ensure the screw heads sit flush. This keeps the assembly looking neat. Additionally, I recommend not driving the screws too deep but working gently, as the boards are not very thick.

Another tip: When pressure is applied, the screws prevent the modules from slipping against each other and help keep the structure stable. This also helps avoid extra strain on the construction.

One last consideration: If you plan to take the modules apart later, choose self-tapping or preferably screwable fasteners carefully. I also like to use metal brackets inside for additional support that can be easily removed.

How large is your KALLAX system currently (number and height)? And where will it mainly be placed?

Le_kin schrieb:
How large is your KALLAX system currently (number of units and height)? And where will it mainly be placed?

Thanks for all the tips and for asking!

I currently have 4 units—two side by side with two more stacked on top, so basically a 2x2 configuration. The units are in the living room next to a window but not in direct sunlight. The height is about 1.2 meters (4 feet), so not very tall but already above eye level when sitting.

I use the shelves for books, plants, and decorations, so quite a variety of weights.

Your advice on pre-drilling and screws is interesting—I definitely want to avoid damaging the typical white front of the KALLAX.

In your opinion, is fastening the units together worthwhile even for a 2x2 setup, or does that only make a noticeable difference with larger constructions?

From a practical perspective: Screwing KALLAX units together is especially beneficial when stability and safety are priorities, such as with taller stacks or frequent rearranging.

In a 2x2 layout, the risk of slipping or tipping is generally lower because the surface area is large enough and the units are relatively heavy.

However, fastening the units together increases resistance to lateral movement, which can be advantageous, for example, when there are children, pets, or during cleaning.

If you have fragile decorative items that are heavy, connecting the units might also be useful.

It should be noted that screwing can create stress between the units under load, which may put localized strain on the material. Therefore, using fasteners with a slight allowance to prevent material distortion is recommended.

In summary: For a 2x2 KALLAX setup, screwing is not strictly necessary but provides good additional security.