ᐅ The corners of the KALLAX in the bathroom are developing mold – have you tried using silicone sealant?

Hello everyone,

Some time ago, I placed a KALLAX cabinet in my bathroom to store various items and towels. However, I have noticed that especially in the corners where the cabinet meets the wall and floor, the silicone joints start to develop mold. I suspect this problem is due to moisture and the fact that these corners are not sufficiently ventilated.

My specific question is: Does anyone have experience with whether the silicone used with KALLAX (or the included silicone sealant, or silicone specifically recommended for KALLAX) is suitable for this? Or would it be better to use a different sanitary silicone to prevent mold growth in the long term?

I am also open to tips on proper preparation and maintenance of these seals to keep the corners clean permanently.

Thanks in advance for your feedback!

Rico59 schrieb:
Does anyone have experience with whether the silicone from KALLAX (or the supplied silicone sealant or specifically used silicone for KALLAX) is suitable for this purpose? Or is it better to use a different sanitary silicone to prevent mold growth in the long term?

Hello Rico59,

to address your question directly: the standard silicone often supplied with furniture like KALLAX is usually not specialized sanitary silicone with fungicidal additives. This means it is waterproof but not necessarily mold-resistant. Especially in bathrooms, where moisture and condensation on seals are common, this can lead to mold formation.

My advice: use 100% sanitary silicone with mold protection (fungicidal additives). These are specifically designed for humid environments.

Before reapplying sealant, be sure to thoroughly remove all old silicone residues. The surface must be dry, free of grease, and clean. Cleaning with alcohol or an appropriate cleaning agent helps ensure the new silicone adheres optimally.

Additionally, make sure your bathroom is well ventilated, as this significantly helps prevent mold. Without sufficient ventilation, mold spots will reappear over time, even if the best silicone is used.

In short: no, the standard silicone from the furniture manufacturer is usually not ideal. It’s better to use sanitary silicone with special additives and ensure proper surface preparation.

Rico59 schrieb:
Does anyone have experience with whether the silicone from KALLAX (or the included silicone seals or specially designed silicone for KALLAX) is suitable for this purpose?

The issue of mold forming in the seals of KALLAX units in bathrooms is more complex than many might think. Since the KALLAX shelf unit is not originally designed for wet areas, using silicone on the edges is more of a workaround.

Important to know: The so-called "included silicone seals" are often not high-quality sanitary silicones with fungicides but standard furniture silicones. These usually do not have adequate mold resistance.

If you want to avoid mold permanently, I recommend the following steps:

1. Completely remove the old silicone. This can be done with a special silicone remover or carefully by mechanical means.
2. Disinfect the surface with an anti-mold agent to kill any spores that might be present.
3. Use a certified sanitary silicone with fungicidal properties. These products are offered by manufacturers like Sika, Otto Chemie, or Bostik.
4. Prevent water from pooling at the seals. Do not place the KALLAX unit directly on the floor; instead, use small feet or a base.
5. Ensure sufficient air circulation around the unit—using a fan or regularly opening windows helps.

One more tip: Moisture sensors or hygrometers can help you detect when the bathroom becomes too humid, so you can ventilate accordingly.

If you like, I can also provide recommendations for suitable types of silicone.

TYRELL schrieb:
Avoid letting water collect in the joints. Do not place the KALLAX directly on the floor; use small feet or a base instead.

This is an important point I would like to add.

Static moisture caused by standing water promotes the growth of microorganisms, especially mold. Placing furniture directly on tiled or damp floors significantly increases this risk.

In addition, the material used in KALLAX is usually particleboard with a melamine coating, which can swell when exposed to moisture. This leads to damage and additional cracks that serve as entry points for mold.

Conclusion: To ensure the longevity of the furniture and prevent mold growth, it is advisable to use raised supports and ensure proper sealing with professional-grade sanitary silicone.

kuben schrieb:
Make sure your bathroom is well ventilated, as this is essential to prevent mold.

I would like to add something to this: I am very familiar with the problem of mold forming on silicone seals and can confirm that using fungicidal sanitary silicone alone is not enough if the humidity in the room remains high or if there is poor air circulation around those areas.

What helped me was regularly airing out the room by fully opening windows and even using small electric dehumidifiers, especially during winter. I also moved the cabinet a few centimeters (inches) away from the wall to improve airflow behind the furniture.

It is also important not to apply silicone too thickly, so it can dry faster and offers less surface area for mold to develop.

I hope this helps a bit, as I know how frustrating this issue can be.