In a sub-membrane depressurization system, how should the soil gas retarder be positioned?

In a sub-membrane depressurization system, the correct positioning of the soil gas retarder is essential for its effectiveness in mitigating radon and other soil gases. The soil gas retarder should be securely fastened to the walls, creating a proper seal. This ensures that the soil gases cannot escape into the living spaces of the structure.

By securing the retarder, it effectively helps in maintaining the necessary pressure differentials that allow the system to function optimally. It prevents gas infiltration and contributes to the creation of a pressure barrier that minimizes radon accumulation below the membrane. This approach aligns with best practices in radon mitigation systems.

Other options, such as loosely placing the retarder on the ground or suspending it in the air, would not provide a sufficient barrier against soil gases and could lead to gas leakage into the home. Not requiring a soil gas retarder is also not appropriate, as it is critical for the performance of the sub-membrane depressurization system.