I renovated my Northcote house but the drains still block. Why?
Because renovations almost always upgrade what you can see and rarely touch what you cannot. New bathrooms, ensuites and laundries add fixtures and water volume, but if they discharge into the same original clay sewer line the house has always had, that line is now carrying more than it ever did — often through joints that have already opened and roots that are already present. A CCTV inspection shows whether the existing line can realistically cope or whether it needs relining or replacement.