ᐅ KALLAX Tip: How deep can you recess a shelf?

Hello everyone,

I am currently planning to recess an IKEA KALLAX shelving unit into a niche to fit it more precisely and slightly flush with the wall. This raises the question: How deep can the shelving unit be recessed without compromising the stability or functionality of the shelves and back panels?

I want to use as much depth as possible without the shelves tipping forward or the back panel becoming too loose. Are there any practical experiences regarding how many centimeters (inches) the KALLAX unit can be recessed at most?

Additionally, it would be helpful to know if recessing the unit could interfere with the installation of the shelves or the insertion of boxes and doors.

Looking forward to your assessments and tips!

To be clear: You can recess the KALLAX shelf up to its full depth of about 39 cm (15 inches) by default. However, if you install it deeper, you will lose the stability of the back panel, as it is only 3 mm (0.1 inches) thick and fastened from the back.

It’s better to ensure that the back panel lies as flat as possible against the wall. Allowing a little clearance at the front edge is advisable so that the shelves don’t get stuck and the boxes don’t jam.

BOMILAN schrieb:
You can recess the KALLAX shelf unit by its full depth of about 39 cm (15 inches) as standard.

That is true in theory, but when recessing it into a niche, there are several factors to consider beyond the nominal shelf depth of about 39 cm (15 inches).

The KALLAX shelves have an installation depth that consists of the thickness of the side panels plus the shelf depth. The external depth of the units is 42 cm (16.5 inches), while the usable depth for boxes and shelves is approximately 33-36 cm (13-14 inches), depending on how the back panel is positioned.

If you want to install the unit flush with the wall or niche, you should ensure the back panel fits flat and does not shift. The back panel is only 3 mm (0.12 inches) thick and is usually nailed or slotted in, which does not provide much stability. If you recess the unit deeper than the standard shelf depth, this might affect the attachment of the back panel or even cause it to be missing, making the unit unstable.

Additionally, shelves could be affected by uneven cutouts or pressure marks.

My recommendation: recessing by 1-2 cm (0.4-0.8 inches) is generally uncritical; going deeper should only be done if you firmly nail the back panel or replace it with a custom back panel. Otherwise, it’s advisable to cleverly bridge the gap with battens or similar supports.

Could you please describe in more detail how deep the niche is and how you plan to fix the side panels? That would help provide more precise advice for installation 🙂

Filippo schrieb:
My recommendation: recessing by a maximum of 1-2 cm (about 1 inch) is uncritical; any more should only be done if you either nail the back panel firmly or replace it with a dedicated back panel.

I completely agree. Recessing beyond the standard shelf depth always carries risks for stability and function.

To explain in more detail: The stability of a KALLAX shelf primarily relies on the firm connection of the back panel to the side panels. This back panel provides lateral stability and prevents the shelf from twisting. If the shelf is installed deeper than intended, the back panel has less contact surface, and the stabilization is compromised.

If you still want to recess the shelf deeper, it is recommended to either use an additional thin plywood back panel or secure the shelf to the niche with brackets to avoid problems later due to a wobbly unit.

Also important: Make sure that drawers, boxes, and doors can still slide in and out smoothly—this is often the main issue when recessing too deeply.

I hope this helps with your planning!