Retaining Walls in Markland Wood

The western edge of this neighbourhood is Etobicoke Creek, which also forms the boundary with Mississauga, and the golf course follows the creek through its valley. Houses that back onto it often have rear yards that start flat at the patio and then tip downhill, sometimes gently, sometimes sharply enough that the bottom half of the lot is just slope and brush. That slope is the main reason people here start thinking about walls.

A single tall wall at the top of the bank looks tidy on paper, but it concentrates all the soil pressure and all the water in one place. We'd normally break the drop into two or three shorter walls with level ground between them. Each tier gets its own clear stone and perforated pipe, and the water is carried toward the rear of the lot, not back toward the house or sideways into the next yard. Height has a paperwork side too: under the Ontario Building Code, a wall over 1 m of exposed height can need a permit when it sits next to public property, a building entrance or a space the public uses, and shorter tiers usually avoid that question.

Old walls on these lots tell their own story. Railway ties and landscape timbers put in decades ago rot at the base, and dry-stacked stone bellies out where nothing let the water escape. Before any design, we look at the City's ravine mapping and at TRCA's regulated-area mapping. Lots near the valley can fall under Toronto's Ravine and Natural Feature Protection by-law or TRCA's regulation, and either one can affect grading, tree removal and where a wall is allowed to go.