ᐅ KALLAX with Subfloor Hardness Issues – Should You Place Wood Underneath?

Hello everyone,

I recently bought a KALLAX shelf unit from IKEA and am now facing an issue: my floor is uneven and quite hard in some areas (concrete with a thin laminate). Because of this, the shelf isn’t stable, tipping slightly in different directions and causing an unpleasant creaking noise due to small movements when walked on.

My question to the community is: Is it advisable to place wooden strips or thin wooden panels under the KALLAX shelf to compensate for the floor’s hardness and unevenness and to improve stability? What type of wood would be suitable, and how should this be done to ensure the shelf ultimately stands stable and without gaps?

I would prefer not to buy new feet, as the shelf is meant to sit directly on the floor. Thanks in advance for your tips and experiences!

Wood shimming usually works well to compensate for uneven floors with KALLAX. It’s best to use thin, sturdy wood panels, such as plywood or beech. Simply place them under the shelf, adjusted to the uneven spots. Avoid using wood that is too soft, as it wears out quickly.

rimole schrieb:
Using wooden shims usually works well to compensate for uneven floors under KALLAX.

That may be true, but I think it’s important to consider the root cause more closely: KALLAX is actually designed for level surfaces. If the floor is too hard and uneven, adding wooden shims might help in the short term, but there is a risk that uneven pressure on the shims could cause wobbling again.

Batar47 schrieb:
Which type of wood would be suitable here, and how should one proceed to ensure the shelf ultimately stands stable and without gaps?

I would suggest measuring the floor hardness or at least clearly marking the uneven spots. Wooden strips are one option, but if the floor is extremely hard and uneven, thin rubber mats or flexible pads could also be useful to provide lasting stability. What do you think about alternative materials?

enrique7 schrieb:
If the floor is too hard and uneven, placing wood underneath might help temporarily, but there is a risk that uneven pressure on the wood pieces will cause wobbling again.

That’s a valid point, and I’m quite familiar with the uncertainty these issues bring. I had a similar situation with my KALLAX on an uneven tiled floor and chose a wooden underlay. What was important for me was to measure very precisely and sand the wood so the pieces fit perfectly.

It’s definitely worth trying – adding wood underlay can noticeably improve stability and prevent more serious damage. If possible, I would even recommend attaching small rubber or felt pads under the wooden strips. This reduces slipping and cushions minor movements.

It’s important not to treat this only as a temporary fix, but to adjust it carefully. Have you thought about whether you want to cut the wooden underlay yourself or buy it pre-cut?