Why does the ANSI-AARST mitigation standard not recommend caulking and sealing alone to mitigate radon?

The recommendation against using caulking and sealing alone to mitigate radon is based on the finding that these methods have not demonstrated a significant or consistent reduction in radon levels. While sealing cracks and openings can be a component of radon mitigation, relying solely on these techniques does not adequately address the complexities of radon entry and distribution within a building.

Radon gas can enter through various pathways, including soil gas infiltration and poorly sealed joints and connections, among others. Caulking and sealing may address only some of those pathways and often fail to sufficiently lower radon concentrations, as it does not eliminate the source of the gas or provide an effective means for radon to be vented away from the indoor environment. Therefore, a more comprehensive approach that might incorporate ventilation systems or sub-slab depressurization is necessary for effective radon mitigation.

This understanding is aligned with the ANSI-AARST mitigation standards, which focus on proven methods that incorporate more holistic approaches to ensure effective reductions in radon levels, rather than relying on methods that only target specific entry points without fully addressing the broader issue of radon ingress.