Why it matters
Asbestos is a known human carcinogen. When its fibres become airborne and are inhaled, they can cause asbestosis, lung cancer, and mesothelioma, often decades after exposure, and there is no established safe level of exposure. The critical distinction: asbestos is dangerous when it is disturbed, cut, sanded, drilled, broken, or pulled out, which is exactly what renovation and demolition do. Health Canada's guidance is that intact, sealed, undisturbed material is low-risk and is generally best left alone. So for a buyer there are two real issues: never disturb suspect material unknowingly, and understand that removing it, if you plan to renovate, can be a major, expensive, professionally-managed job.
How to spot it
You cannot confirm asbestos by sight, only a lab test of a sample can, and even taking that sample should be done carefully (ideally by a professional, since sampling itself disturbs the material). The suspects to treat as "test before you touch" are: textured/popcorn ceilings in pre-1990 homes; grey or brown crumbly pipe and duct wrap; vermiculite (small, pebble-like, grey-brown loose-fill attic insulation); and old vinyl-asbestos floor tile and its black mastic.
What it costs
Lab testing of a sample is modest (roughly $50 to $100 per sample plus lab fees). Removal is where it gets expensive, and it varies enormously by scope. A small, contained job, a length of pipe wrap or one small area, might run $1,000 to $3,000. But major abatement is routinely a five-figure cost: removing vermiculite attic insulation commonly runs $10,000 to $30,000+, and whole-house work (popcorn ceilings throughout, extensive pipe insulation) can exceed that. The strict containment, negative-air setup, certified disposal, and worker-safety requirements are what drive the price. Treat any home with widespread suspect materials as a potential five-figure expense if you intend to renovate.
What to do
Do not sand, cut, scrape, drill, or remove suspect materials yourself, disturbing asbestos is exactly how it becomes dangerous. If the material is intact, the safest move is to leave it sealed and undisturbed. Before any renovation in an affected area, have suspect materials sampled and tested by an accredited laboratory, and removed only by a licensed asbestos abatement contractor working under your province's occupational-health-and-safety rules. Budget abatement into reno plans, use a confirmed presence as a negotiation point, and if you have any health concern about exposure, speak with a medical or occupational-health professional.
Education and triage, not a home inspection. Casaroo flags suspect asbestos-era materials so you don't disturb them unknowingly, it cannot confirm asbestos and is not a substitute for professional testing or abatement. Only an accredited lab confirms it, and only a licensed abatement professional should remove it. We flag; we don't certify.