Almondia – Bautipps Die Bauherrenberatung

mud building

Earth building has a long history. Regardless of whether you think of traditional half-timbered houses, the activist village in front of the nuclear waste storage facility in Gorleben in the 1980s or even the Japanese imperial palace – clay as a building material always has positive connotations. It is considered to be particularly environmentally friendly because it can be permanently recycled, is kind to the skin and also reduces the fine dust content in the room air, which is a big plus for allergy sufferers in particular.
In addition, clay offers good sound insulation and, above all, keeps the humidity in the room constant, which guarantees a permanently pleasant living climate. But one fear threatens to overshadow all these benefits: Is clay radioactive? This article has summarized the answers to this complex question for you in a nutshell.

the essentials in brief
Clay is known to most as a reliable and ecological building material, but research into increased radioactive concentrations has raised concerns.

However, these are not substantiated with data, since the level of the actual pollution has not yet been sufficiently investigated and environmental certificates also classify the building material earth as harmless.

In general, attention should be paid to adequate ventilation in order to reduce pollutants in the room air.

Brilliantly good material

For a long time, adobe remained in the minds of the general public as a popular, environmentally friendly building material. Some time ago, however, the reputation that was once so good was called into question: Clay releases radioactive substances into the air and the values could be up to 4.6 millisieverts per year in a house built entirely of clay. This exceeds the official limit set by the WHO, which is just 3.0 millisieverts. Clay therefore appears to pose a health risk. If this is actually the case, the values mentioned above would significantly increase the risk of lung cancer.

Such claims naturally stir up fears among all owners and potential builders of mud houses that are supposedly so health-friendly. Many construction companies that work with clay clearly reject the accusations and state that the harmlessness of the building material has been confirmed by the Natureplus seal of approval. The Sentinel House Institute also classifies earth building as completely harmless.

Is there reason to worry about earth building?

The fact is that all rocks emit radioactive isotopes and the fact that clay also emits radioactive substances is therefore nothing unusual.
Since thorium, which is found in clay, has a very short half-life compared to, for example, radon, it was ignored in radiation protection for a long time. However, since lower doses of natural radioactivity are now also considered to be harmful to health, researchers in the Helmholtz Group have started to investigate the issue more closely.

In general, however, it is probably somewhat generalized to currently speak of clay as a radioactive threat. The investigations are still ongoing, and the umbrella organization for earthenware affirms that the quality of earthen building materials is always based on the latest scientific research and that there is therefore no reason for health concerns about earthenware construction.

Clay rendering on straw
Plastering a straw wall with clay

Simply detoxify room air

Basically, however, clay is not the only culprit one way or the other: the largest dose of radioactive decay products is released into the room air from the floors, especially in the basement. Therefore, a certain amount of radioactive substances in the room air can hardly be avoided – but you can actively counteract this. You have to ensure adequate ventilation, especially in new buildings and buildings that have been insulated afterwards. Regardless of whether it is clay or other building material: In order to reduce the concentration of pollutants in the room air, the right ventilation strategy is recommended.

So far there is no scientific evidence that earth is harmful as a building material. The studies on the subject are ongoing, but there is no immediate reason for concern. Various certificates also assure harmlessness. If you live in an adobe house or plan to use adobe as a material in your home, it is of course worth keeping an eye out for new research results – but this applies to all building materials. If you are concerned about the level of pollutants in your indoor air, you can often achieve a much greater positive effect with the right ventilation techniques than choosing a different building material.

Autorin Sarah Völkl

Sarah Völkl hat Architektur studiert und ist seit Jahren das Gesicht von a better place. Mit ihren Videos ist sie bei YouTube vielen Personen schon länger bekannt. Sarah teilt Ihr Wissen jetzt auch bei den Bautipps von Almondia.
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