Answers to the questions people actually ask.

Nothing, they’re the same thing. ADU (Additional Dwelling Unit) is the term most people search for. ARU (Additional Residential Unit) is Ontario’s official term, used on your permit application.

Yes, always. A second suite needs a building permit, has to meet the Ontario Building Code and has to pass inspections, with no exceptions for a basement conversion or a garden suite. An unregistered unit isn’t legal even if it’s already built and occupied, and that creates real problems later with insurance, financing, tenant disputes and resale.

Almost certainly yes, in some form. Ontario requires most urban residential lots to allow up to three units as-of-right: the main house, a basement suite and a garden suite. The exact rules on top of that vary by municipality and lot, which is why the first real step is always a property-specific check.

It depends on your budget, timeline and how much privacy you need. Short version: a basement apartment for the lowest cost and fastest rent, a garden suite for full privacy and no shared walls.

Roughly $80,000–$175,000 all-in, depending on the current state of the basement and how much egress and fire separation work is needed.

Roughly $200,000–$300,000+, because it’s a full new structure with its own foundation and its own water, sewer and hydro connections. That servicing work alone is a large part of the gap versus a basement conversion.

Most homeowners stack more than one source: a HELOC against the home, sometimes a municipal grant where one exists, sometimes a refinance against the property’s post-renovation value. We’re not a lender, so talk to a mortgage broker about what fits your situation.

It can. If you build a garden suite and rent it out, you may be treated as a “builder” for HST purposes, which can trigger a tax obligation based on the suite’s fair market value once your first tenant moves in. It’s a real cost some homeowners don’t budget for: talk to an accountant before you commit, not after.

For a basement apartment, roughly 3–5 months from design to occupancy. For a garden suite, roughly 6–12 months, since it’s new construction on its own schedule.

For a complete application that meets zoning, commonly 4–10 weeks for a basement apartment and 8–16 weeks for a garden suite, though it varies a lot by municipality and how busy the building department is at the time. We’ll give you a realistic number for your municipality at the feasibility stage.

Four, in order: a feasibility check on your specific property, permit drawings (building and HVAC, done in-house here), permit submission to your municipality, then approval and construction.

Yes: a licensed contractor to build it and, depending on scope, a Licensed Electrical Contractor for the electrical, filed separately with the ESA. Structural work, if any is needed, is coordinated with an outside licensed professional. We prepare the building and HVAC drawings and coordinate the rest.

It depends entirely on your municipality. Some require an additional parking space for a second unit, some don’t if the property is within walking distance of transit. It’s one of the property-specific details we confirm at the feasibility stage rather than guess at.

Almost always, yes. A second suite is a material change to how the property is used, and most home insurance policies need updating to reflect it. Talk to your insurer once the unit is legal and registered, not before.

Often, yes, once it’s legal and registered as a second unit, but it depends on your market and we can’t promise a number. It’s a real factor buyers and their lenders look at.

The unit isn’t legal, no matter how good the work is. A future buyer’s lender won’t count it, it isn’t insurable the way a legal unit is, and it’s one bylaw complaint away from an order to bring it into compliance or vacate it. It’s also why we’re upfront about that risk before quoting drawings for a unit that’s already built without a permit.