Choice of mitigation method

Shallow-foundation house, ground-supported slab

• primary method sub-slab suction or radon well
• efficiency improvement measures when necessary (ventilation, underpressure, sealing)
• improvement of ventilation or reduction of underpressure alone have rarely resulted in considerable (over 50%) reduction
• sealing alone is a very demanding operation, if the aimed reduction is over 50%

Houses with cellar and hillside buildings

• primary method sub-slab suction or radon well
• efficiency improvement measures when necessary (ventilation, underpressure, sealing)
• separately ventilated cellar enables mitigation based on ventilation of the cellar
• need to seal ground-supported walls, lightweight concrete block walls
• storage rooms located in the cellar may constitute significant leakage routes

Monolith slab

• check penetrations
• cracks may increase leakage

Crawl-space construction

• ensure and improve crawl space ventilation
• sealing of base floor, penetrations
• check underpressure ratios of building