Detached Garage Cost: What to Budget for a New Build in 2025
A new detached garage costs $20,000–$70,000 depending on size, finish level, and whether you want it conditioned. Here's the full cost breakdown.
A detached garage is one of the more complex structures a homeowner can add to a property — it requires its own foundation, framing, roofing, electrical, and often plumbing, plus permits and setback compliance. The cost range is wide because the use case varies enormously: a basic two-car shelter looks nothing like a finished workshop with climate control and a bathroom.
Detached Garage Cost by Size
Size is the most straightforward cost driver. Labor and material costs scale roughly linearly with square footage, though there are fixed costs (foundation, electrical panel, permits) that make smaller structures less cost-efficient per square foot.
| Garage Size | Square Footage | Typical Installed Cost |
|---|---|---|
| 1-car basic | 12 x 20 ft (240 sq ft) | $20,000–$35,000 |
| 2-car basic | 20 x 20 ft (400 sq ft) | $30,000–$50,000 |
| 2-car finished | 20 x 22 ft (440 sq ft) | $45,000–$70,000 |
| 3-car basic | 30 x 22 ft (660 sq ft) | $50,000–$80,000 |
| 3-car with apartment above | 30 x 22 ft + 660 sq ft ADU | $100,000–$180,000+ |
"Basic" means slab, framing, roof, siding, garage door, and a basic electrical circuit. "Finished" means drywall, insulation, heating, finished floors, dedicated panel, and usable lighting throughout.
The Major Cost Line Items
Foundation and Slab
The foundation is the base cost that doesn't scale much with size. A concrete slab for a two-car garage runs $5,000–$12,000 depending on thickness, reinforcement, site prep, and local labor rates. In areas with expansive soils, the engineer may specify deeper footings or a thickened edge slab — ask about soil conditions during your permit process.
If the garage will have a bathroom or floor drain, plumbing rough-in needs to be done before the slab is poured. Retrofitting plumbing into an existing concrete slab is expensive and disruptive — plan ahead.
Framing and Structure
Detached garages are framed one of three ways: stick-built on site (most common, most flexible for custom layouts), post-frame/pole barn construction (faster, cheaper, common in rural areas, limited finish options), or prefab steel kit (economical, faster to erect, but limited in finish and resale appeal).
Stick-built framing for a 2-car garage runs $8,000–$18,000 for framing labor and materials, depending on wall height, roof pitch, and complexity. A flat roof is cheaper to frame than a gabled or hip roof — though a steeper pitch gives you bonus storage loft potential.
Roofing
A detached garage roof follows the same cost structure as a house roof — shingles, decking, underlayment, flashing, gutters. Budget $5,000–$10,000 for roofing on a standard 2-car garage. If you're matching your house's existing roofing material (tile, metal, cedar shake), costs rise accordingly.
Garage Doors
A standard single steel door (8x7 or 9x7) runs $500–$1,200 installed. A double door (16x7) runs $800–$2,000 installed for a basic insulated model. Carriage-house style, glass-paneled, or wood doors can run $3,000–$8,000 per door installed. Add $400–$800 per door for an opener with keypad and connectivity.
Electrical
Every detached garage needs its own electrical subpanel — running off the main house panel. The subpanel and feeder line from the house is typically $1,500–$4,000 depending on distance and amperage. A 60-amp subpanel handles lighting, outlets, and a basic shop. A 100-amp panel supports EV charging, larger tools, and HVAC.
EV charging adds $500–$1,200 for a Level 2 hardwired charger. A 240V welder or air compressor outlet is $200–$400 per circuit.
Conditioned Space (HVAC)
An uninsulated garage is a storage structure. A conditioned garage — one where you actually work comfortably year-round — requires insulation and climate control.
Insulating the walls and ceiling of a 2-car garage adds $2,000–$5,000. A mini-split heat pump for heating and cooling a 400–500 sq ft garage runs $2,500–$5,000 installed. A propane or natural gas unit heater is cheaper upfront ($800–$2,000 installed) but costs more to operate.
Permits and Setbacks
Detached garage permits are required in virtually every jurisdiction. The permit process will surface setback requirements — minimum distances from property lines, easements, and other structures. These are non-negotiable. If the lot can't accommodate a garage at your desired size while meeting setbacks, the size must come down or the location must shift.
Permit costs for a detached garage run $500–$2,500 depending on jurisdiction. Some municipalities charge based on project valuation. Plan for 2–6 weeks for permit approval in most suburban jurisdictions.
Garage Apartment / ADU Above the Garage
Adding an apartment above a detached garage is one of the most efficient ADU paths available — you're amortizing the foundation and structure across both uses. Cost for the above-garage unit itself runs $50,000–$120,000 depending on finish level, plumbing (kitchen and bath), separate entrance design, and local ADU regulations.
California ADU rules have become substantially more permissive since 2020 — if you're in Southern California, a garage apartment may qualify for streamlined permitting. Verify current rules with your local planning department or a permit expeditor before assuming.
Prefab Garage Kits vs. Site-Built
Prefab steel or wood garage kits are available from many suppliers for $8,000–$20,000 (kit price only). They look cheaper than site-built until you add: foundation, electrical, finishing work, permits, and the labor to assemble the kit itself (which isn't free). All-in, a prefab kit often lands 15–25% cheaper than site-built for a basic structure — meaningful savings, but narrower than the kit price implies.
For a finished, conditioned garage that you'll use as a workshop, studio, or ADU, site-built construction gives you more design flexibility and better long-term finish quality.
What Kills Garage Budgets Mid-Project
Underground surprises — old septic systems, buried utilities, rock ledge, or groundwater discovered during excavation can add $3,000–$15,000 in mitigation costs. A site assessment before breaking ground helps, but doesn't eliminate the risk.
Utility connections — if the garage is far from the house (more than 50 feet of feeder run) or requires a new utility service, electrical costs escalate quickly. Get the electrical quote after the location is confirmed.
HOA and CC&R restrictions — some neighborhoods prohibit detached garages, limit height, require architectural approval, or restrict exterior materials. Get written HOA approval before signing with a contractor.
Planning a detached garage or workshop addition? Schneider Construction and Development offers remote bid review nationwide and on-site GC services in Southern California — contact hello@schneidercondev.com to get started.
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