A properly installed radon system includes airtight sealing of cracks, cold joints

https://www.scribd.com/document/1009143037/Radon-Mitigation-St-Louis-Incentives-and-Rebates-to-Know-137784

A properly installed radon system includes airtight sealing of cracks, cold joints, and utility penetrations to prevent radon from bypassing the suction field.