Concrete patios in Toronto
Toronto's housing base is older and more vertical than anywhere else we build in. More than half of all homes predate 1980, and nearly half of all dwellings sit in high-rise buildings, which means a genuine backyard patio realistically exists on a minority slice of the city's total housing, mostly the single-detached and semi-detached stock. A lot of that stock is itself pre-war, so a patio replacement job in Toronto is very often undoing decades of a slab poured tight against the house with nothing isolating the two.
The ground under a Toronto patio depends heavily on where in the city the lot sits. The older, lower parts of the city rest on fine-textured clay and silt left behind by Glacial Lake Iroquois roughly 12,500 years ago, ground that drains slowly after rain or snowmelt and falls into the same "clay or soils not clearly defined" category that sets Ontario's 1.2 metre minimum footing depth for anything unheated. Higher ground further from the lake, in the city's northern reaches, sits on a different glacial till entirely, so soil conditions here vary block to block more than in almost any other city in our service area, which is exactly why we confirm the specific address rather than assume one soil type city-wide.
None of that changes the concrete spec. A Toronto patio still gets 32 MPa, air-entrained concrete at a 0.45 maximum water-cementitious ratio, the same exposure class we use on a driveway, since it is freeze-thaw cycling and chloride tracked in from a nearby salted walkway, not vehicle load, that the mix is actually built to resist. Anywhere the slab meets something already rigid, the foundation wall, an old walkway, a pool deck, an isolating joint goes in at that contact, because leaving two surfaces to expand on their own timetable is how a seam starts spalling.
On an older Toronto lot, a patio replacement often means re-planning joint layout around curves, borders and whatever the original slab ignored the first time. Joint layout over an old pour is a shared lakeshore problem: backyard concrete patios in Mississauga and exposed aggregate patios in Oakville run into the same seam where a decades-old slab met the foundation with nothing between them. See our concrete steps and concrete walkways work on the same kind of Toronto property, browse the patio gallery, or check everything we build across Toronto.