"How to eliminate radon in a house" has about 170 searches per month, difficulty 17. The site ranks around 54th place. Eliminating radon is not about keeping windows open all year. It is about preventing soil gas from entering living spaces.
1. Measure
Without numbers, it is impossible to know if work is needed. The 4-day test detects radon. The 91-day test shows exposure during normal living conditions. Both products are priced at $74.72 taxes included (detector $39.99 + return and laboratory $25 + taxes).
2. Compare to 200 Bq/m³
Health Canada recommends action above 200 Bq/m³. The WHO uses 100 Bq/m³ as a reference. Below 200, keep the result. Above, plan for correction. Threshold details are in what level is acceptable.
3. Extract gas from under the slab
The common method is sub-slab depressurization. A pipe passes through the slab, a fan runs continuously and vents air from under the foundation to the outside. Opening windows only lowers levels while open. Sealing a crack without a fan does not fix a slab that draws soil gas.
The standard installation costs $2,799.99 + taxes. The price is confirmed before work begins. The lowest price guarantee is 5% below a written quote from a competitor for a comparable installation. Requests can be made on the attenuation page or by calling 418-681-7964. The system operation is described separately.