Go Far®The short answer
In the Seattle–Snohomish County market, a straightforward attached garage typically runs about $60–$100 per square foot, and a detached garage about $70–$120 per square foot once you include the foundation, roof, siding to match the house, and an electrical feed. In real numbers: a one-car garage (roughly 240–320 sq ft) usually lands around $25,000–$45,000, a two-car (400–576 sq ft) around $40,000–$70,000, and a large two-story or three-car build $70,000–$120,000+. National averages are lower — but so is national labor, and Puget Sound sites are rarely flat, dry, and simple.
What drives the price
- Foundation and site work. The slab itself is cheap; getting to it isn’t always. Slopes, drainage, tree roots, and a driveway extension are the most common budget-movers on our garage projects.
- Matching the house. A garage that looks like it was always there — matched siding, rooflines, and windows — costs more than a kit building and is worth every dollar at resale.
- Power. A lights-and-outlets feed is modest; a shop panel with 240V circuits for welders, compressors, or an EV charger typically adds a few thousand dollars, and is far cheaper to do during construction than after.
- Finish level. Insulation, drywall, heat, and built-in storage turn a parking spot into a year-round workshop — and move a detached build toward the top of its range.
- Doors. A quality insulated door with an opener runs $1,500–$4,000+ installed; carriage-style and glass-panel doors climb from there.
Permits and rules
Garages are real construction: a building permit, setback and lot-coverage rules, and inspections apply in every city we serve, and attached garages must meet the energy code where they touch conditioned space. The good news is that a garage is one of the simpler permits a homeowner can pull — our permit guide explains the process, and as your contractor we handle all of it.
Worth considering: build it ADU-ready
Washington’s statewide ADU law lets most urban lots carry up to two accessory dwelling units — and a garage that is one day converted into living space is the cheapest path there. Building ADU-ready costs surprisingly little upfront: a slightly deeper foundation, plumbing rough-ins where a bath could go, taller plates, and insulation now instead of later. Done that way, a garage conversion down the road skips the expensive retrofit work. A garage with a full apartment above is a different animal — the living portion prices like an addition at $300–$550 per square foot — but it is one of the best-value ways to get a backyard rental because the garage below shares its foundation and roof.
Garage, carport, or shop?
A carport is cheaper but adds little value; a fully finished shop with heat and 240V power is a lifestyle upgrade that buyers in Arlington, Monroe, Snohomish, and Lake Stevens actively hunt for. If you’re weighing a garage against other ways to add space, our home addition cost guide and remodel ROI guide show how the options compare. When you’re ready for a real number on your lot, request a free estimate — we’ll price it from your actual site conditions, not a national average.