Sub-Slab Depressurization (SSD)
SSD is the most common radon mitigation technique installed in residential homes. In this technique, a piping system and radon fan are installed to extract radon and other soil gases from beneath the home and discharge them outdoors. When these systems are properly designed and installed, they can reduce radon levels in a home by up to 95 per cent.

Sub-Membrane Depressurization (SMD)
SMD is used to reduce radon concentrations where an exposed soil/ rock crawlspace exists in the basement or a sealed crawlspace is present under some or all of the house. With this approach, the radon is extracted from beneath a polyethylene sheet placed over the exposed sub-surface materials and discharged from the house using a fan/pipe combination.

Alternative Approach - Heat Recovery Ventilators (HRV)
HRV can be an effective solution if a home has multiple air quality concerns and is equipped with an HVAC system with ducting. An HRV system allows for an exchange of outdoor and indoor air while partially saving energy and reducing heating/cooling costs associated with the exchange of air. When installed and maintained properly, an HRV can reduce radon concentration by approximately 50 per cent. It must be noted, that for an HRV system to remain effective it requires continuous maintenance.

Health Canada's Radon Reduction Guide for Canadians can help explain the options available to homeowners.