Tips against mould in the apartment

Last updated: 25. November 2021

mildew in the home is a very annoying affair. Not only does it look unattractive, it is also unattractive: mould can cause diseases such as respiratory problems and even allergies and asthma. Children in particular are at risk and should be kept away from a room where mildew is known.

In fact, it would be even better to keep children away from an infected home, as the dangerous mould spores spread quickly across the room air.

A certain number of mould spores is normal and also quite natural, the human body copes with it without problems. But as soon as, for example, a wall is affected by mould and the number of spores in the air rises, it becomes dangerous for humans and animals.

The term mold fungus is a general term under which a multitude of different types are united, which are still far from all investigated. The toxins of the moulds are called mycotoxins and they can already lead to health problems in small quantities. We may also encounter the mycotoxins in food, e.g. in the form of aflatoxins in nuts and pistachios.

The danger in the living room is mainly caused by the spores, which can spread throughout the whole house at lightning speed, without you being able to see or smell them. 

Not every mould is also harmful

. Penicillium fungus is/was used in medicine for the production of penicillin. And a camembert gets its characteristic taste from the noble mould.

Here the differences of the fungus types commonly known as “moulds” become particularly clear. Moulds are of unbelievably high importance for the ecological survival.

However, they should not occur in the living rooms, so here are some useful tips for you on how to avoid mould in your home.

mold tip 1 Avoid mold by proper ventilation

If you want to avoid mould in your home, you must ensure proper ventilation. This means: great shock ventilation, if possible with draught, instead of having the window permanently on tilt.

Window open for butt venting

The background to this is as follows: Moulds love moisture. Moisture that we produce permanently. Not only when cooking, showering and bathing, but also when breathing. In a 4-person household, about 12 litres per day come together, and if this mass of moisture does not find its way out, then sooner or later it forms the perfect breeding ground for mould.

Particularly at risk are the kitchen, bathroom and the rooms in which laundry is dried. Aerate intensively three to four times a day, especially after cooking, showering and bathing.

If possible, set up a draught by opening a window or door on the opposite side of the apartment/house at the same time.

mold tip 2 prevent mold behind furniture

A popular place for mold, where it can remain undetected for a long time, are the walls behind furniture, or the back walls of the furniture itself.
The reason for this is that even with generous ventilation, for example behind cabinets, there is no air exchange.

This mould growth behind the furniture can be easily avoided by placing the furniture at least 5 cm – 10 cm from the wall.

mold tip 3 Avoid mold with the correct room temperature

Correct room temperature

To avoid mould growth, it is important that the temperature in the rooms is right. The following table provides information about the ideal temperatures of the individual rooms:

16 – 18 °C

roomideal temperature
Living & Working Rooms20 °C
Children’s room20 – 22 °C
Kitchen18 °C
Bathroom23 °C
cellar10 – 15 °C

It is therefore important not to let the rooms cool down, as happens very quickly when the window is permanently open during the cold months. As already described under point 1, the best variant is short shock lifting with pull-through.

After the airing the room will warm up very quickly because the heat is still stored in the walls, floors, ceilings and furnishings and is now released back into the air.

With long ventilation, however, the walls etc. would also be cooled, which is why much more energy is needed to reheat the room. Shock ventilation not only prevents mould, but is also more cost-effective and environmentally friendly.

mold tip 4 Remove mold from the base: Check humidity

Correct relative humidity with hygrometer<

Another very important factor for the formation of mould is the relative humidity in the room. First of all: what information is hidden behind the term “relative humidity”?

The air can only absorb a certain amount of water vapour, and this amount depends on the temperature. A cubic meter of air at a temperature of 0 degrees Celsius, for example, can absorb 5 grams of water vapor. The amount increases with temperature, and so a cubic meter of air at 30 degrees Celsius can already absorb 30 grams of water vapor.

The “relative humidity” always refers to the percentage of air load (i.e. saturation). If there is 30 grams of water in one cubic meter of air at 30 degrees Celsius, then the relative humidity is 100%. For 15 grams of water 50% accordingly. When the air is saturated, the gaseous state of the water cannot be maintained and drops of liquid are formed. This condensation, but also relative humidity values of over 70%, favour mould extremely, from 80% it is practically unavoidable.

The exact values shown in the following table should be observed for the individual rooms.

dtd>40% – 60%

dtd>40% – 60%

dtd>40% – 60%

dtd>50% – 60%

dtd>50% – 70%

dtd>50% – 75%

roomIdeal relative humidity
Living & Working Rooms
Children’s room

You need a hygrometer to measure relative humidity. This allows you to read the relative humidity in the living rooms at any time.

mold tip 4a reduce humidity in the room

If the humidity in the room is too high, there are several ways to lower it.

  • Aerate well: as already described, regular aeration should be sufficient to reduce the humidity to an acceptable level. If there is no window in the room, the moisture can still be removed through open doors over other rooms.
  • House remedies (salt, rice and cat litter): a very inexpensive home remedy for air dehumidification are salt, cat litter and rice. Use the hygrometer to find out where in the room the humidity is particularly high and place small containers with commercially available salt, cat litter or rice. Moisture from the air is absorbed by it.
  • Dehumidifiers: those who are willing to invest some money can also buy an electric dehumidifier. For smaller rooms around 20 m², devices of around 100 €, which consume around 50 watts, are sufficient. With larger rooms you have to dig a little deeper into your pocket – not only the purchase price of approx. 300 € is significantly higher, also the power consumption of approx. 150 watts is three times higher than the smaller compact devices. If the airing and the small bowls with cat litter or salt are not sufficient, then an electric dehumidifier is still the clearly better option than exposing oneself to mould. By the way: the commercially available dehumidifiers without electric operation can be saved, since they are basically nothing else than the household means. A slightly different material is often used to absorb moisture, but this is not much more effective than salt and cat litter, but much more expensive.

Wiping the shower dry: you can reduce the risk of mould in the bathroom by wiping the tiles or walls of the shower after showering with a window wiper. The drops of liquid that end up directly in the drain in this way will no longer evaporate and thus also will not increase the room humidity. In addition, the particularly endangered areas, such as the joints, can be disinfected. This is where apple cider vinegar comes in. The easiest and fastest way to do this is to spray the apple vinegar onto the endangered areas with a spray bottle – wiping is not necessary. Caution: Vinegar must not be used on calcareous materials such as marble.

Mold tip 4b Increase humidity

Even if the humidity is too low, it is important to take measures to bring the humidity to the right level.

  • Aerate well: the simplest way to bring the humidity into the optimum is to aerate with draught. .
  • Use the humidity of other rooms: if there is a room with high humidity nearby, for example a bathroom, you can simply divert the humidity of this room into the dry room. Simply leave the doors open after showering or bathing. The humidity will then be evenly distributed in the rooms. Make sure, however, that it is not too high and in case of doubt open an additional window.
  • Defined houseplants: with houseplants that require a lot of water, the humidity can also be increased. The following plants are suitable for this:

Gerbera sword fern “Bostoniensis”

Gerbera narrow
ArecapalmeAreca palm narrow
  • drying clothes: if the dry room is warm enough, you can hang your freshly washed clothes there to dry. As a lot of moisture is released, it is all the more important to check the hygrometer.
  • Humidifiers: you should only use a humidifier if all the other measures do not help you. The reason why this is the last choice is that many humidifiers promote the spread of germs. They usually have a water tank that heats up and provide the perfect livelihood for germs. They multiply there in the water, and are then distributed everywhere. Therefore, it is generally not recommended.

mold tip 5 remove mold itself

Rubber gloves for mould removal

New mould that does not exceed one square metre can be removed quite easily. However, two things must be taken into account: the mould may only be present on the surface! If it sits deeper, for example due to water damage or a defective pipe, it is imperative that a specialist is appointed.

And the second point is that sufficient self-protection must be provided:

  • a P2 breathing mask to avoid inhaling spores
  • protective glasses against eye irritation
  • Rubber gloves to prevent allergic reactions on skin contact

Two household remedies are available for the treatment of superficial mould: vinegar essence and 70% alcohol or methylated spirit. Before treating the surface, always test on an inconspicuous area whether the material tolerates the treatment. Colourful wallpapers, for example, are very likely to discolour.

mold tip 5a vinegar essence against mold

Pour the vinegar essence onto a cloth or sponge and wipe away the mould. The low pH value of the vinegar essence fights effectively on smooth surfaces, since most types of mould do not tolerate a low pH value. Then wipe again with a damp cloth. However, this does not work with calcareous material (marble), as the acetic acid reacts with the lime and dissolves the material. You can observe this reaction when descaling your kettle.

Dispose the cloth or sponge with household waste afterwards. It is essential to ensure adequate ventilation of the rooms, as vinegar essence can irritate the respiratory tract.

mold tip 5b alcohol and methylated spirit as mold killer

Alcohols with 70% alcohol content or methylated spirit also work very well as mould removers. Just as with vinegar, simply rub it on the affected area. In contrast to vinegar, however, alcohol does not have a direct harmful effect on the mould, but merely removes the moisture and thus the food basis from it. Therefore it is necessary to repeat this treatment more often. The alcohol content should also not be too high, otherwise it will evaporate too quickly. 70% is a good compromise here.

Dispose the cloth or sponge with household waste afterwards. It is essential to ensure adequate ventilation of the rooms, as alcohol/spirit should not be inhaled for long periods of time.

There are two other ways to remove mould. Both variants are associated with substances that should not be touched or inhaled directly on no case.

mold tip 5c mold control with chlorine

Everyone knows the smell from indoor or outdoor pools where chlorine is used to keep the bath water free of germs.

Many commercially available antifungal agents are based on chlorine or chlorine-like substances, however, they should only be used in the bath, if at all, and then aired well. Chlorine vapours are toxic, so they should not be used in the kitchen, bedroom or other living areas where you are staying longer.

Chlorine is generally unsuitable for wallpapers and textiles, as it usually leads to discolouration.

Mold tip 5d Use hydrogen peroxide against mold

Not only can you bleach your hair or disinfect the swimming pool with hydrogen peroxide (H2O2), but you can also use a solution of at least 5% to combat mould.

Wear protective clothing and make sure that the room is well ventilated. The substrate to be treated must be dry. If necessary, you can help here with a hairdryer. The disinfecting effect kills both active fungal cells and conidia, i.e. sources of spores.

Hydrogen peroxide is available in DIY stores or pharmacies. Also in the Internet one can order solutions problem-free, one should evenly only pay attention that the H2O2 portion amounts to at least 5%, since the effect is otherwise too weak.

Mold tip 6 have mold removed by specialists


Have mold professionally removedIn general, if the area affected by mold is larger than 1 m², a specialist company should be consulted.

In this case, a specialist company should be consulted.

In case of an infestation larger than 1 m² the probability is very high that the mould has already penetrated deep into the walls. Treatment with the household remedies described above with subsequent wiping is no longer sufficient – you only expose yourself unnecessarily to a health hazard if you wipe away the mould, and after the treatment it grows back from the depths of the masonry.

Therefore, the wall must be opened and disposed of by a specialist company with the appropriate equipment. The costs for this are usually borne by the owner or landlord, unless the landlord can prove that the mould was caused by misconduct on the part of the tenant. To do so, he must demonstrably exclude his own area of responsibility (construction defects, etc.).

As a tenant, you can contact the landlord directly, as he is responsible for organising the removal of the mould. Failure to meet his responsibility may be a reason for a rent reduction. However, one should really be sure that the mould was not caused by one’s own fault, but by poor insulation, leaking pipes or other defects of the building. Anyone who gets mould through incorrect ventilation is not entitled to a reduction in rent, unless the incorrect ventilation was used to compensate for a building defect.

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