Radon Mitigation Systems Photo Album: Crawlspace Mitigation, Raleigh

Initial Conditions Existing active radon mitigation system Approximately 3,000 sq. ft. vented crawlspace Unsealed, loosely installed vapor barrier Radon level of 4.9 pCi/L with mitigation system operating Our Assessment The existing mitigation fan remained suitable for the application, but the collection system beneath the crawlspace was fundamentally limited. Instead of a sealed sub-membrane depressurization system, 2-inch PVC piping had been routed beneath the loose vapor barrier in multiple directions. Without an airtight membrane, the system could not efficiently develop negative pressure beneath the crawlspace floor. Our Solution After discussing several options with the homeowner, we installed a sealed crawlspace barrier system. The project included: New sealed crawlspace barrier Complete redesign of the collection piping Two extraction points for improved pressure distribution across the large crawlspace Reuse of the existing mitigation fan, which remained properly sized Results Starting radon level: 4.9 pCi/L Final radon level: Below 1.0 pCi/L This project demonstrates that successful radon mitigation depends on system design, not simply adding more suction. By creating an effective sealed collection area beneath the crawlspace and properly distributing suction with multiple extraction points, we were able to dramatically improve system performance while retaining the existing fan.