Radon for landlords the tenant’s bedroom is the occupied zone
A four-unit building does not have one level. The basement unit and the ground-floor unit touch the soil. The ones above touch it much less. Measure the units where people live in contact with the slab, or just above it.
One report per unit
Even a semi-detached house, even a duplex: one detector per unit that is occupied regularly. Keep the report with the building file. If it is above 200 Bq/m³, the correction is suction under the slab, not an air purifier. It is not a purifier.
Between two leases
A 91-day test needs the unit occupied and heated as usual. Starting it while a tenant lives there gives a useful number. The tenant can also order it: tenant guide.
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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