From the point of view of healthy buildings, we are developing some articles about radon to see how this gas can be dangerous for our health if it is accumulated inside buildings. But, once we have identified where we are exposed to radon gas, it is essential to understand how this gas enters the building and why.
How does radon get into a building?
The main entrance for radon to a building is the building envelope. A wrong design or execution of building solutions in the envelope, or a bad choice of the materials involved in the strategy of isolation, allows gas to leak through any gap that has not been properly covered (unwanted air infiltrations).
These access points can appear in any element of the envelope: floors, walls, roofs, etc. We can summarize by saying that access of radon gas into a building is due to the lack of tight insulation.
As the air is the element that carries radon particles, barriers to air in the envelope of the buildings are necessary. This concept, which is used in environments related to passive houses and almost zero energy buildings, has a key role in building a healthy environment.
Strategies of building envelopes that promote the infiltration of radon
Lack of insulation systems
A large number of the constructed buildings do not have an insulation system in their envelope. Accordingly, undesired air infiltrations are greater and situations such as a bad energy performance of the building or a filtration of external contaminants can take place.
A non-continuous thermal insulation
Choosing a thermal insulation material that creates execution joints between its plates facilitates the infiltration of air between such joints. The contact between the different elements is especially conflictive (pillar-forging, façade-forging, etc.)
Auxiliary elements in the execution of building solutions
If the components of the building envelope, such as thermal insulation, are not continuous, then we will need a series of auxiliary elements that will complicate the implementation and maintenance of the work. The more joints of execution there are the easier for unwanted agents and particles to get in (such as radon gas).
Analyzing different insulation solutions
In the document "Radon in buildings: How does radon get into a building?" we make a comparison between different insulating materials from the point of view of tightness. Download the document for further details.