A garage addition means building new attached or detached garage space where none existed, tying it into your home's roofline, foundation, and sometimes its heating and electrical systems. A conversion is the opposite move: taking an existing garage and turning it into livable space, a bedroom, home office, gym, or in-law suite, which means dealing with insulation, subflooring over a slab, moisture control, and often a full reworking of the old garage door opening. Both jobs sit at the intersection of framing, foundation work, and permitting, which is why they're usually handled by builders who do additions generally rather than garage specialists alone.
In Ottawa, this work also has to account for our frost depth (footings typically need to go down around 4 feet), snow load requirements on any new roof structure, and the city's permit process for structural additions and change-of-use conversions. A contractor who skips the permit step on a conversion can leave you with space that doesn't count as legal living area, which matters at resale and for insurance.
When comparing builders, look at how they handle the foundation-to-existing-house tie-in, whether they pull permits as a matter of course, how they detail insulation and vapor barrier on conversions, and whether their quotes break down materials versus labor clearly. Our scoring weighs verified customer feedback, how consistently a company follows through on permits and inspections, and the range and complexity of projects they've actually completed, so you're not just going on star ratings alone.
See how the 8 local companies compare in our ranked guide to garage additions and conversions in Ottawa, and read our methodology for how we score and verify each one.
