ᐅ KALLAX in the Bathroom and Mold – Does Anyone Have a Solution?

Hello everyone,

I recently set up a KALLAX shelving unit from Ikea in my bathroom to store towels and toiletries. Unfortunately, after some time, mold started to appear on the back panels and partly inside the shelves within the bathroom. The bathroom is relatively small and tends to be humid due to showering, but I ventilate regularly and maintain basic airflow.

My question for you: Who has experience with KALLAX furniture in bathrooms and can offer recommendations on how to effectively protect the material from moisture and mold? Are there special sealants or other measures you would use?

I would prefer not to give up the shelving unit since it is practical, but the mold is concerning. Thanks for any tips or solutions based on your own experience!

Hello leiksar,

KALLAX shelves are made from MDF boards with a melamine coating, which can be susceptible to moisture and mold growth when exposed to consistently high humidity levels.

I recommend disassembling the shelf completely and removing the back panels first. After sanding off any visible mold spots, the wood should be treated with an anti-mold wood preservative. It is also important to seal it with a moisture-resistant paint or a clear polyurethane (PU) coating.

Additionally, the air exchange in your bathroom should be improved – an automatic exhaust fan often works better than relying on manual ventilation alone.

If the shelf is directly against a wall, creating ventilation space using spacers can help reduce moisture buildup.

I hope this helps.

Hello leiksar,

I’m familiar with this issue. The combination of MDF and humidity in the bathroom is often problematic. In addition to Dwight’s tip, I would add: keep the humidity levels below 60% over the long term. Proper ventilation means not just briefly opening the windows but ideally airing out the room several times a day with cross-ventilation.

If you still want to keep the shelf, I recommend sealing the backs and edges with acrylic or silicone sealant. You can also apply protective wood preservatives using impregnation sprays.

Some people also use moisture absorbers (e.g., silica gel packets) inside the shelf compartments.

If you can use a fan, that helps a lot. There is a good chance of preventing mold growth permanently.

Mold in the bathroom is always a sign of excessive humidity. Do not place the KALLAX directly against the wall; air circulation is important. Use breathable paints or varnishes on all visible surfaces.

Dwight49 schrieb:
KALLAX shelves are made of MDF panels with a melamine coating, which can be vulnerable to moisture and mold growth when exposed to consistently high humidity levels.

That makes sense. I knew about MDF, but not these details regarding the melamine coating. Are there any recommended wood preservatives available on the market that are specifically suitable for bathroom furniture?

RON57 schrieb:
Keep the humidity level below 60% in the long term.

What is the best way to measure the humidity in the bathroom? Would simple hygrometers be sufficient, or is another type of device more appropriate?

I understand that ventilation is important, but it’s quite difficult in my bathroom, so I am trying to support it with technical solutions.

leiksar schrieb:
Are there any recommended wood preservatives available that are specifically suitable for bathroom furniture?

Yes, brands like Xyladecor or Baufan offer mold-resistant wood preservatives that are also suitable for use in damp rooms. Make sure the products have fungicidal properties and are approved for interior use.

leiksar schrieb:
What is the best way to measure humidity in the bathroom?

A digital hygrometer is sufficient and affordable. Some devices also measure temperature and display the dew point — this is ideal. Additionally, a data logger can be helpful if you want to monitor humidity levels over several days.

This significantly improves your understanding of moisture-related issues.