Sealing cracks is not enough the gas finds the next opening
Radon enters through slab cracks, joints, the space around pipes, the sump, the drain and sometimes the foundation walls. Filling one with caulk or epoxy closes that hole. Soil pressure pushes the gas toward the next hole. A painted slab is not a measurement.
The fix that holds is a slight suction under the slab: the gas is pulled before it enters, then exhausted above the roof. Caulk helps that system by limiting air leaks from the house into the gravel. On its own, it is not compared with 200 Bq/m³.
Sump. Passive or active. The system.
Reference points: Health Canada, what you need to know about radon and the 200 Bq/m³ guideline. The two-year timeline between 200 and 600, and one year above 600, comes from Health Canada’s guide for radon measurements in homes.
The 4-day test gives a first reading. The 91-day test covers the three-month minimum Health Canada asks for. Both are $59 before tax: shipping, return and the laboratory are included, taxes extra. The PDF report is sent within 2 business days after the laboratory receives the detector.
Above 200 Bq/m³, mitigation is confirmed with a quote. Gaz Radon is C-NRPP certified for measurement and mitigation.
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