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How to Prevent Mold and Damp Walls in Zurich Apartments

Mold on wall near window frame in a Zurich apartment caused by moisture and condensation

Mold removal in Zurich is a common need during the winter months, as many rental apartments suffer from condensation, damp walls, and poor ventilation. When moisture builds up, mold can spread quickly and cause both structural damage and health risks.

Mold in Zurich apartments is more common than many tenants expect. Cold winters, high humidity, older buildings, and poor ventilation can quickly lead to damp walls, condensation, and black spots around windows or corners. Besides looking unpleasant, mold can affect your health, damage the property, and even create conflicts with your landlord.

The good news: in many cases, mold and damp walls in Zurich apartments can be prevented with the right habits, simple improvements, and timely professional help.

Why Mold and Damp Walls Are So Common in Zurich Apartments

Zurich’s climate and building style create perfect conditions for mold growth:

  • Cold winters and warm interiors
    When it’s cold outside and warm inside, moisture from breathing, cooking, and showering condenses on cold surfaces. Especially outside walls, corners, and window frames.

  • Older or poorly insulated buildings
    Many Swiss rentals, especially in older buildings, have thermal bridges: cold spots in the construction where moisture condenses faster. North-facing rooms, stairwell walls, and uninsulated concrete can become permanently cold and damp.

  • Lack of proper ventilation
    Modern tenants often keep windows closed to save energy. But without regular fresh air, humidity rises inside the flat, and warm moist air settles on the coldest surfaces, ideal for mold.

  • Everyday humidity sources
    Drying clothes indoors, long hot showers, cooking without lids, or lots of plants in small spaces add significant moisture to the air.

Put simply: if humidity stays high and surfaces stay cold, mold will appear, and yes, even in clean, well-kept apartments.

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What Tenants Can Do to Prevent Mold (No Landlord Approval Needed)

As a tenant, you can’t change the building structure, but you can control your habits and indoor climate. Here are practical, landlord-safe actions to prevent mold in Zurich apartments.

Ventilate correctly
  • Use short, intense “shock ventilation” (Stosslüften):
    Open windows fully for 5–10 minutes, several times per day, instead of tilting them for hours.

  • Ventilate after showering, cooking, or drying clothes to remove moisture quickly.

  • If possible, open windows on opposite sides of the flat briefly to create a cross-breeze.

Heat consistently (not just “a bit”)

Turning the heating off completely during winter can make walls cold and damp. Instead:

  • Keep rooms at a steady, moderate temperature (around 19–21 °C in living areas).

  • Avoid extreme temperature swings; they encourage condensation.

  • Don’t heat only one room and leave others cold – humidity will migrate and condense on the coldest surfaces.

Pay attention to furniture placement
  • Avoid placing large wardrobes or sofas directly against outside walls.

  • Leave a few centimetres space between furniture and walls so that air can circulate.

  • Check behind furniture regularly for early signs of damp or mold.

Manage indoor humidity
  • Dry clothes in well-ventilated rooms or on the balcony if allowed – not in small bathrooms without windows.

  • Use lids when cooking and turn on the extractor fan if available.

  • Consider a dehumidifier in very humid rooms, especially basements or ground floor flats.

  • Avoid overcrowding small rooms with plants and aquariums if you already struggle with moisture.

These simple habits can significantly reduce the risk of damp walls and mold in Zurich apartments without changing anything permanent in the property.

What to Do If You Already Have Mold

If mold has already appeared, it’s important to act quickly and calmly.

For small, surface-level mold

For small areas (for example, a few dark spots around windows or on bathroom joints):

  • Wipe the area with a suitable mold cleaner (often alcohol-based products; avoid harsh bleach on porous surfaces).

  • Wear gloves and, if possible, a simple mask to avoid breathing spores.

  • Ventilate well before and after cleaning.

  • Check why it formed there: is it always cold? Is there condensation? Is furniture too close?

If the mold does not return after improving ventilation and heating, the problem was likely related to surface humidity and everyday habits.

For recurring or large mold patches

If mold covers a larger area, keeps coming back, or the wall feels damp to the touch, it may be more than just poor ventilation:

  • There could be water infiltration, damaged seals, plumbing leaks, or structural damp behind the wall.

  • Cleaning the surface only hides the problem temporarily – the cause remains.

In these cases, you should never just paint over mold or ignore it. It’s time to involve your landlord and, if necessary, a professional.

Professional Mold Removal Services in Zurich, St. Gallen & Nearby Areas

If moisture or mold has already appeared on your walls, ventilation and heating tips might not be enough. In that case, it’s important to act quickly — mold spreads fast and can damage both the apartment and your health.

MyProfessional.ch connects you not only with handymen, but also with specialists trained in mold removal who can assess the cause, eliminate the problem safely, and prevent it from returning.

Our mold removal experts in Zurich can help with:

  • Professional mold inspection and moisture diagnosis

  • Safe mold removal from walls, ceilings, and windows

  • Treating hidden mold behind furniture or drywall

  • Installing or improving ventilation to prevent recurrence

  • Sealing drafts and fixing humidity-related issues

These professionals understand Swiss rental regulations and can advise you on what is your responsibility and what must be handled by the landlord — helping you avoid disputes about damage or deposit deductions.

Need urgent mold removal?
 Find a trusted mold specialist or handyman in Zurich today and protect your rental from long-term damage.

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Frequently Asked Questions

Is mold the tenant’s or the landlord’s responsibility in Switzerland?

In Switzerland, landlords must fix structural moisture problems, while tenants must ventilate and heat properly to prevent mold. If mold appears despite correct ventilation, it’s usually the landlord’s responsibility.

Small surface mold can be cleaned with mild products, but recurring mold or large patches should be handled by a professional. Experts can identify the cause, condensation, leaks, or insulation problems, and provide a long-term fix.

Most winter mold in Zurich rentals is caused by condensation, poor air circulation, insufficient heating, or thermal bridges near windows and exterior walls. Cold weather makes these issues more common.

If the mold spreads quickly, smells strongly, appears black/green, or returns repeatedly, it may require professional assessment. Long-term exposure can affect indoor air quality and health.

Ventilate the room, reduce humidity, and clean only surface-level mold. Then document the affected area with photos and notify your landlord. If the cause is unclear, book a mold specialist to inspect the issue.

Handymen can remove small mold patches, seal drafts, and improve ventilation. For recurring mold or moisture infiltration, a certified mold removal expert is recommended.

Yes. Many professionals offer same-day inspections for urgent moisture or mold problems. Through MyProfessional.ch you can contact available experts directly.