Health Canada has published the results of the second and final year of its survey of radon gas levels in Canadian houses. On average, 7 percent of houses have levels of radon gas above the level at which Ottawa says action should be taken. In some areas of the country, more than 30 percent of homes exceed the guidelines.
Radon gas is produced naturally by the breakdown of uranium in soils and rocks. The gas can’t be seen, smelled or tasted, but it can be detected by inexpensive home testing kits or by a qualified professional. The gas seeps up through dirt floors, cracks in foundation walls and floors, through gaps around pipes.
Renovators can help homeowners deal with radon gas, if it is detected, by increasing basement ventilation, sealing all cracks and openings and, in severe cases, replacing entire basement floors. Recent changes to the National Building Code now require a vapour barrier for all basements and a rough-in for a future radon ventilation systems, should it ever be required.