London is the flattest city we work in, with no escarpment, no moraine and no lake shoreline to complicate a site. What it has instead is heritage. The city has several heritage conservation districts, and Old North sits inside that framework, which means an exterior alteration there needs a heritage alteration permit in addition to the building permit. Wortley Village and the Woodfield areas work the same way. North of the core, Masonville and Sunningdale are post-1980 and post-2000 respectively, with no heritage layer at all.
The Upper Thames River Conservation Authority regulates the river valleys that cut through the city, under Ontario Regulation 41/24, and those valley lots turn up more often than people expect on the older streets. Out west, Kilworth and Komoka are in Middlesex Centre rather than London, with private servicing on many properties. Our basement renovations in London deal with all three of those conditions depending on the address.