ᐅ KALLAX on an Uneven Old Building Floor – How to Secure It?

Hello everyone,

I am currently facing the following problem: I want to secure a KALLAX shelving unit from IKEA on an old, uneven ceiling in an older building. The ceiling has slight irregularities, and I am unsure how to fix the shelf securely and permanently without it wobbling or getting damaged.

I am particularly interested in fastening options that can stabilize the shelf against tipping and sliding when the surface is not completely level. Should I use spacer strips, build a support frame, or are there special brackets or mounting systems that you would recommend?

I would also like to avoid making extensive modifications to the ceiling, so ideally a solution that preserves the existing old ceiling structure.

Thank you in advance for your suggestions and experiences!

Hi meo30,

I’m very familiar with the problem of old floors! For uneven surfaces, a wooden or MDF underlay often helps. You can prepare it in a way that evens out the irregularities – basically creating a small platform for your KALLAX. Then you can simply place the shelf on top, making it more stable while preserving the floor underneath.

When it comes to securing it: in older buildings, you often need to use lightweight nails or special mounting screws that don’t create much dust or dirt 🙂 You could also add non-slip pads under the feet for extra grip.

Sounds like a bit of work, but with some patience, you’ll easily manage it! 🙂

Hello meo30,

There are a few important points to consider when securing a KALLAX shelf on an uneven old building ceiling. First, the KALLAX should not be placed directly on an uneven surface, as it is made of particleboard and uneven pressure can cause premature warping.

I recommend the following steps:

1. Measure the unevenness using a spirit level and, if available, leveling tools.
2. Acquire a leveling base, such as thin plywood or MDF sheets, and adjust it with wooden wedges to create a flat foundation.
3. Attach the base using screws or suitable adhesive, depending on the floor structure.
4. Secure the KALLAX shelf to the wall using mounting brackets, which are usually included by IKEA. This prevents tipping.

Regarding the old ceiling itself, I advise against inserting anchors directly into the ceiling if the concern is only the floor area. Most KALLAX shelves are secured to the wall rather than the floor or ceiling.

In summary: level the floor surface, fix the shelf to the wall, and consider using base material for stabilization.

Juan31 schrieb:
I recommend the following steps:

1. Measure any unevenness using a spirit level and possibly leveling tools.
2. Obtain a leveling underlay...
3. Secure the underlay...
4. Attach the KALLAX shelf to the wall using mounting brackets

This is already quite well phrased, but I would like to go into more detail:

If the floor itself – for example, old wooden floorboards beneath the KALLAX – has slight unevenness, I recommend first creating an accurate profile of the irregularities. For this, a simple tension tape or a long spirit level combined with a profilometer works well. This will determine the natural leveling height.

The best underlay for leveling is sturdy plywood, 10 to 15 mm (0.4 to 0.6 inches) thick, which can be adjusted with small shims or rubber washers. These shims must be firmly fixed (with wood glue or small screws) to prevent any later shifting.

It is also important that the KALLAX is secured to the wall to prevent tipping—especially around children or when bearing heavier loads. IKEA usually provides wall fixing materials for this purpose.

Could you describe the ceiling surface more precisely? Is it wooden boards, plaster, or lime render? Are there major height differences or only minimal ones?

Depending on this, the recommendation can be further refined.

TEBILO schrieb:
Could you specify the ceiling structure? Is it wooden planks, plaster moldings, or lime plaster? Are there large height differences or only minor ones?

Thanks for asking! The ceiling consists of an old wooden plank floor, which is already covered with a thin layer of carpet. I would describe the unevenness as moderate, roughly estimated at about 5-10mm (0.2-0.4 inches) maximum height difference across the surface, so no extreme slope but noticeable waves across the area.

How exactly would you approach the substructure? I imagine I could simply glue the shims to the floor, but I’m unsure how to ensure long-term stability.

Hello meo30,

here is my structured recommendation for your KALLAX on an uneven wooden plank floor:

1. Preparation: Thoroughly clean the surface from dust and carpet residues.
2. Leveling Board: Use a plywood board about 12 mm (½ inch) thick as a base. It is dimensionally stable and durable.
3. Marking Height Differences: Place the board on the floor and mark the spots where there is air underneath.
4. Wedge Creation: Use wooden shims or thick felt pads to place under the marked spots to create an even support.
5. Fixing: You can attach the wedges to the board with wood glue. Then place the entire setup on the floor without screwing it down, so you can fine-tune the positioning.
6. Wall Fixing: The shelving unit should always be secured to the wall with the included metal brackets. This prevents it from tipping over.

Important: Avoid screwing directly into your old wooden floorboards, as they might give way or break. The system with the leveling board plus wedges provides a stable base and easily compensates for unevenness.

If you like, you can also place rubber pads between the floor and the leveling board to increase grip and reduce noise.