What condition makes crawl space depressurization the most appropriate choice?

Crawl space depressurization is an effective radon mitigation strategy, particularly in situations where the crawl space can be isolated and is inaccessible for other forms of remediation. When the crawl space is not easily reachable or modified, creating a depressurization system can effectively mitigate radon levels without needing direct access to the space for maintenance or major alterations.

In cases where the crawl space can be sufficiently isolated, a depressurization system can help draw radon gas from beneath the foundation and vent it outside, reducing the risk of accumulation indoors. This method is particularly advantageous when other mitigation strategies, such as sub-slab depressurization, cannot be implemented due to physical access limitations or structural considerations.

Other conditions such as low humidity levels in the crawl space, new construction with vents, or the presence of a sump pump do not necessarily support the effectiveness of crawl space depressurization for radon control. Low humidity may not directly impact radon levels, and vented crawl spaces or those with sump pumps could alter the air dynamics in ways that may not make depressurization the optimal choice for mitigation.