We had such a remediation done recently, in Alberta close to the rocky mountains.
Costs were around $2,000 CAD to install a sub-slab depressurization system (i.e. a fan that pulls air from below the house and vents it away from the house).
Radon values dropped from around 500 Bq/m3 to less than 20 Bq/m3.
Costs were around $2,000 CAD to install a sub-slab depressurization system (i.e. a fan that pulls air from below the house and vents it away from the house).
Radon values dropped from around 500 Bq/m3 to less than 20 Bq/m3.