The third Radon Task Group meeting focused on reviewing the September 19, 2025 Record of Discussion and related action items. CHBA requested a clarification in the RoD to reflect its recommendation that the Task Group examine research by the National Research Council (NRC) or Canada Mortgage and Housing Corporation, which informed the 2010 NBC requirements on radon and depressurization in Part 9. This ties directly to NRC’s recent findings on how active mitigation systems affect home depressurization.

MB Radon Solutions presented field-based insights on radon rough-ins and active subslab depressurization systems. The presenter highlighted practical challenges and voiced strong opposition to including active (fan-based) radon mitigation systems in the Code. Concerns centered on the risk of builders installing these systems without certified radon professionals, potentially compromising safety, effectiveness and contributing to unintended consequences (i.e. condensation on foundation walls).

Following the presentation, the Task Group was unable to reach consensus on whether to move forward with the proposed Code change for active mitigation systems. Additionally, the review of clearance requirements for sidewall systems was postponed to a future meeting.

The agenda package can be found below.

For any questions, please reach out to Jack.Mantyla@chba.ca