Bleach and other cleaners: what helps against mould
Humid air on cool walls can cause mould to form in a very short time. The first visible signs are dark spots and discolouration on the walls of the room. Comparis shows how you can permanently remove mould.
23.12.2022
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1. Why does mould form?
Mould spores are naturally contained in indoor and outdoor air. If they come into contact with the appropriate breeding ground, mould can develop. Moist and cool surfaces in indoor areas are particularly affected.
Insufficient room ventilation, poor thermal insulation or water entering from outside can cause moisture on the wall. This provides the mould with an ideal substrate.
2. Is mould a health risk?
Moisture and mould can put your health at risk. The health risk also increases as the mould infestation worsens. Mould infestation can cause irritation to the skin, eyes and respiratory tract.
In addition, mould can cause allergies as well as frequent colds. In people with severely weakened immune systems, mould can lead to serious illnesses and infections.
3. How can I remove mould?
How you deal with mould depends on the severity of the infestation. As an immediate measure, you should ventilate the room often. Also find out the cause of the moisture and mould growth.
If you live in a rented apartment, inform the landlord as soon as possible. Otherwise, you may be held liable for consequential damages. Your landlord is responsible for dealing with the situation. You can clear a small mould infestation yourself.
Removing small mould stains
You can wipe off small mould stains on smooth surfaces with water and a little household cleaner. Wear plastic gloves when you do so.
According to the Federal Office of Public Health, you should also disinfect rough surfaces with a bleach solution or ethyl alcohol. Do not use vinegar. The acid is quickly neutralized. The remaining organic components then provide the mould with a source of food and promote growth.
Contact with bleach solution can cause serious reactions such as burns and irritations. When removing mould with bleach, it’s therefore important to adhere to the following rules:
Keep bleach away from children.
Use gloves and avoid contact with eyes.
Don’t mix or store the bleach with acids or acidic detergents. This can produce toxic chlorine gas.
Don’t mix the bleach with ammonia. There is a risk of explosion.
Always store bleach in its original container and observe the information on the label.
Before cleaning the full surface, check whether the chemical causes any damage in a hidden place.
Clearing large areas of mould
Large areas of persistent mould infestations should be removed by a specialist. It’s usually not enough to wipe off the mould and paint the affected wall again to prevent further mould.
The roots of the mould extend a few centimetres deep into the wall and are not killed by the paint. After some time, the dark spots will appear again. Specialists in structural damage and building physics can also assess the need for further renovation measures.
Ventilate regularly for a few days after the mould has been removed. This reduces the amount of spores and mould in the air of the room.
Comparis tip
The Federal Office of Public Health (FOPH) publishes the brochure “Caution – Mould” available to download online (not available in English). Here, the FOPH divides the mould infestation into damage categories in a detailed table and provides information about the necessary steps.
4. How can I prevent mould?
Furnish the apartment properly
In the worst-case scenario, the mould spreads from the wall to pieces of furniture. You should therefore place furniture at a distance of five to ten centimetres from the wall.
Don’t place large cabinets and cupboards against external walls.
Having many house plants and drying laundry in the apartment lead to increased humidity and thus promote mould formation.
Replace porous jointing material as quickly as possible. Water seeps through loosening joint seals on sanitary and kitchen fittings and promotes mould growth.
Heat properly
Turn on the heating in time. The walls should not be allowed to get cold.
Don’t leave individual rooms completely unheated. Exceptions are the basement and the attic. These are designed as cold rooms.
Don’t delay putting the heating on, especially for buildings with poor thermal insulation. Heat to about 20°C. For well-insulated and ventilated buildings, you can lower the room temperature to 18°C.
Set the right temperature on the thermostat
Many thermostats are marked with the numbers one to five instead of degrees. The numbers represent the temperatures:
* (asterisk): Frost protection – the heater only runs at temperatures below around 5°C.
Level 1: approx. 12°C
Level 2: approx. 16°C
Level 3: approx. 20°C
Level 4: approx. 24°C
Level 5: approx. 28°C
This means that if you want to heat your bedroom to around 18°C, turn your thermostat to level 2.5.
Ventilate properly
You should ventilate regularly throughout the year. This is especially important when your heating is on.
The humidity should be between 30% and 50%, on very cold days at 40%. If windows are fogged up or dew drops form, the air is too humid. It’s best to measure the humidity with a hygrometer.
5. Tips on ventilation
Ventilate after bathing, showering or cooking.
Dry damp windows, tiles and joints with a cloth or a squeegee.
Don’t ventilate into other rooms.
Continuous ventilation with windows in the tilted position does not help. Moisture isn’t able to leave the home.
Ventilate more frequently in older buildings with new windows and poor thermal insulation or apartments with many occupants.
Don’t ventilate basement rooms during the day in summer. Warm outdoor air cools near the cold basement walls. This results in more moisture.
In the warm season, ventilate the cellar only late in the evening or early in the morning with cool outside air.
In winter, keep the door to heated rooms closed.
Ventilate with wide open windows three times a day for five to ten minutes.
When ventilating, open the windows and doors completely and ensure that they allow a draught.
Ventilate before the windows fog up. Fogged windows are a sign of excessive humidity.
Turn off the radiator while ventilating.
Ventilate even more frequently than described above in the first few weeks due to additional moisture from drying building materials.
This article was first published on 08.08.2019
