Vents soil gas from beneath the foundation to the exterior before it can enter the building.
Cost
Medium
Upkeep
Occasional
Skill to build
Intermediate
Lifespan
Fan: 10-15 years; the sub-slab piping/sump itself is effectively permanent once installed
Embodied carbon
Low
Space / material use
Low
Output timing
Continuous process
Skill to repair
Intermediate
Regulation (FR example)
Radon risk information is compulsory for buildings in category-3 radon-potential communes. Mitigation is not itself permit-bound, but is expected where measured levels are high.
Note: Cost, carbon and footprint are rated against the other options for this same need, not in absolute terms.
What your site needs
A site with elevated radon risk (a genuine, site-specific measurement, not assumed)
US EPA / general radon-mitigation industry durability consensus
What this page does not tell you
No sizing or quantities: how much a technique yields, and how much a household needs, both depend on the build and the people, so the catalogue compares options rather than dimensioning them. It carries no bill of materials and no build sequence, and it is written for an oceanic, clay-soil climate (Normandy, France). Regulatory notes are indicative and need confirming locally.