Cast Iron and Clay in Pre-War Homes
Much of the West Side and East Vancouver housing stock predates the 1950s, which means cast iron stacks and clay sewer laterals that have been in the ground for seventy years or more. Clay joints admit roots, and cast iron scales from the inside until the effective diameter is a fraction of what it was. Recurring backups in an older Vancouver house are usually a condition problem rather than a blockage problem, and camera inspection is what separates the two.
See drain and sewer work