About GTA ADU Builders

We are a Greater Toronto Area construction company that builds one thing: second dwellings on lots that already have a house on them. Garden suites, laneway homes, basement and secondary suites, garage conversions and detached backyard units, across 30 municipalities from Burlington to Georgina. We work as a single established team from the first zoning review to the final occupancy inspection. That means one company reads the by-law, prepares the permit drawings, represents the application at the municipality, and then builds what was drawn. Homeowners who split that work between a designer, a permit expediter and a general contractor usually discover the gaps at the worst moment - when the building department asks a question nobody owns.

That single-team structure exists because accessory dwelling work is governed by three moving rule sets at once: the Ontario Building Code, the municipal zoning by-law for your specific address, and the province's secondary-suite legislation, which has been rewritten repeatedly in recent years. A detail that is routine in Toronto's laneway program - rear-yard setback, angular plane, emergency access route width - is a redesign in Oshawa or Milton. We track those differences municipality by municipality because we file in all of them. We do not sell a catalogue unit and force it onto your lot. The lot decides: laneway access, rear yard depth, servicing runs, frost depth and the municipality's current second-unit rules narrow the options long before anyone talks about finishes.

We start there, tell you what is actually permitted at your address, and price the work honestly against real GTA figures.

We operate as a service-area business across the Greater Toronto Area rather than from a showroom. Assessments happen on your property, where the decisions are. We design, permit and build in 30 GTA municipalities: Toronto and its former boroughs - North York, Scarborough, Etobicoke, East York - plus Mississauga, Brampton and Caledon in Peel; Vaughan, Markham, Richmond Hill, Newmarket, Aurora, King, Whitchurch-Stouffville, East Gwillimbury and Georgina in York; Oakville, Burlington, Milton and Halton Hills in Halton; and Pickering, Ajax, Whitby, Oshawa, Clarington, Uxbridge, Scugog and Brock in Durham.

Each of those municipalities enforces its own zoning by-law for accessory dwellings, so we keep a separate page for each one describing the local rules as they stand.