Mississauga's ARU by-law caps accessory structures at 10% rear-yard coverage, which on a typical Erin Mills lot works out to roughly 645 sq ft - enough for a two-bedroom garden suite but not for the three-bedroom units clients often ask about first. We size the concept to that percentage before drawing anything.
Building an ADU in Mississauga
We design, permit and build garden suites, laneway homes, basement secondary suites and garage conversions across Mississauga, working from Large 1970s-90s subdivision lots with attached garages; garage conversions and rear coach houses are both common outcomes. Mississauga permits additional residential units under its 2022 ARU by-law - up to two units in the main dwelling plus one in an accessory structure, subject to a maximum 10% rear-yard coverage. Homeowners here budget $6,500-$11,000 in City of Mississauga and Region of Peel charges before construction, and we quote that separately from the build so the number is never a surprise at permit stage. Our Mississauga projects run through Port Credit, Streetsville, Cooksville, Erin Mills, Clarkson and the surrounding streets. With 717,961 residents and major employers including Pearson International Airport, Trillium Health Partners, Microsoft Canada, tenant demand for a legal second unit is steady year-round, and the April-November building season shapes when we break ground.
