Physical barrier at the foundation blocking soil gas entry; simpler but less robust than active depressurisation.
Cost
Low
Upkeep
None
Skill to build
Basic
Lifespan
Vapour barrier membrane: 30-50+ years if undisturbed, similar failure mode to the airtight membrane
Embodied carbon
Low
Space / material use
Low
Output timing
None
Skill to repair
Basic
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.
Inputs
none
Outputs
none
Sources
General vapour-barrier 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.