What are the radon levels like in Metro Vancouver and should I test before finishing my basement?

Yes, you should absolutely test for radon before finishing your basement, especially in Metro Vancouver where radon levels can vary significantly even between neighboring properties.

Radon is a naturally occurring radioactive gas that seeps from the ground and can accumulate in basements and lower levels of homes. In Metro Vancouver, radon levels are generally moderate compared to some other parts of BC, but certain areas have elevated readings that exceed Health Canada's guideline of 200 Bq/m³. The Fraser Valley, parts of Richmond, and some areas of North Vancouver have shown higher radon concentrations, while downtown Vancouver and the West Side typically have lower levels.

Testing is crucial before basement finishing because once you've installed drywall, flooring, and ceiling systems, it becomes much more expensive and disruptive to install radon mitigation systems if needed. A simple radon test kit costs $30-50 and takes 3 months for accurate long-term results, or you can hire a certified radon measurement professional for $150-300. The Canadian National Radon Proficiency Program (C-NRPP) certifies professionals in BC - look for this designation.

Vancouver's geological conditions make radon testing particularly important. The region sits on marine clay, glacial deposits, and bedrock that can contain uranium deposits. Homes built on fill, near creeks, or in areas with good drainage may have different radon levels than those on solid clay. Even homes on the same street can have dramatically different readings - one might be at 50 Bq/m³ while the neighbor hits 400 Bq/m³.

If your test results exceed 200 Bq/m³, radon mitigation systems typically cost $1,500-3,500 when installed during renovation, but can cost $3,000-6,000 if installed after finishing. The most common solution is a sub-slab depressurization system - essentially a fan and pipe system that draws radon from beneath your basement slab and vents it outside. This integrates much more easily during the rough-in phase of your basement renovation.

Professional guidance is essential if radon levels are elevated. While you can do the testing yourself, mitigation system design and installation should be done by a C-NRPP certified mitigation professional. WorkSafeBC also has guidelines for contractors working in high-radon environments.

Next steps: Purchase a long-term radon test kit from a hardware store or online, place it in your basement for 3 months (heating season is ideal), then decide on mitigation before proceeding with finishing work. Don't let radon testing delay your project - you can often complete the test while planning and permitting your renovation.