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Radioactive substances in building materials

Radioactive substances in building materials can be of natural origin. Radon is particularly relevant in this context. Naturally occurring radioactive substances accumulate in several residues from industrial processes. Some of them are used as secondary raw materials in the building and construction industry.

Building material: paving stones

Building materials

Through the emission of gamma radiation and the inhalation of radon released in rooms, radionuclides in building materials cause radiation exposure. The mean value of the gamma local dose rate in buildings caused by them is about 80 nanosievert per hour, values above 200 nanosievert per hour are rare. The building materials traditionally used in great quantities in Germany, are generally not the cause for enhanced radiation exposures due to radon in buildings.

Countertop in a kitchenSource: KristinaBlokhin/Stock.adobe.com

Granite plates used in households

In the past, newspapers reported about granite in homes as a source of potential radiation exposure. Natural stone and other building materials contain natural radionuclides, e.g. uranium-238. During the radioactive decay of uranium-238, the radioactive gas radon-222 originates from radium-226. However, in most instances the proportion of radon from building materials and natural stone in homes is small compared to the amount of radon emitted from soil.

Interior with clay plaster

Clay as building material

Common mineral house building materials such as concrete, brick, gypsum and aerated concrete contain natural radionuclides. It is currently a matter of debate whether unfired clay building materials may result in radiation exposures critical to health, because unfired clay can emit the radioactive gas thoron into indoor air. Unlike radon of which both the occurrence in buildings and health effects have been studied well, thoron requires further research to facilitate a reliable evaluation of its health implications.

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