Converting a Garage Into an ADU in Sacramento — A Contractor's Honest Guide
A garage conversion is the ADU most Sacramento homeowners should at least price before anything else, because it's almost always the cheapest and fastest route to a legal second unit. The walls, the roof, and the footings already exist — you're finishing a building, not raising one. But a garage was built to shelter a car, and turning it into a place someone sleeps brings a specific set of Sacramento realities: the old slab, the ceiling height, the fire-rated wall on an alley lot, the SMUD wrinkle, and the City-versus-County counter. We convert these for a living, so what follows is the version we'd give a neighbor over the fence, not a brochure.
Why the garage is usually the cheap path
The reason a conversion wins on price is simple arithmetic. A detached ADU makes you pay for a brand-new foundation and a brand-new roof; those two items alone can run $40K to $70K on a small unit. A garage conversion reuses both. You're buying interior framing, insulation, windows, finishes, and the systems that make a space livable — not a whole new shell. For a Sacramento homeowner staring at a 380 to 480 square-foot garage, that's the difference between a project that pencils and one that doesn't.
Detached garages, the kind that sit at the back of a lot off an alley, convert especially cleanly. Midtown, Oak Park, parts of Curtis Park, and the older grid east of downtown are full of them — single-car and double-car garages from the 1920s through the 1950s, many opening onto the alley. Because they already stand free of the house, the conversion gives you a true detached unit with its own entrance and yard separation, but at conversion prices instead of new-build prices. That combination is hard to beat.