The total cost to build a detached garage is around $28,000, or about $40–$70 per square foot, according to BobVila. The actual cost, however, depends on materials, labor, and customizations.
Fortunately, with a little knowledge about what goes into the costs of a detached garage, you can bring the price tag down a lot. A prefabricated metal garage starts at around $9,000 for a single-car metal garage, plus the cost of a concrete slab.
Read on for a thorough breakdown of materials and factors to consider when pricing a detached garage for your home.
Attached vs. Detached Garage: Cost Differences
While both garage types serve the same purpose, their cost of building and associated materials can vary significantly. Below are key cost-related differences between attached and detached garages:
- Attached garages are typically less expensive. They share a wall and foundation with the house, reducing materials and labor costs.
- Attached garages can be included in a home’s mortgage. This can offer more favorable financing terms than a standalone build.
- Detached garages offer more affordable material options. They can be made from metal or other budget-friendly materials, unlike wood-framed attached garages.
- Detached garages allow for greater customization. Detached garages don’t need to match the home’s structure, making it easier to add lower-cost features.
- Cost depends on customizations. The final price for either garage type hinges on the add-ons and finishes you choose.
Detached Garage Prices by Size and Dimensions
To calculate the cost of a detached garage, you need to know the size that best fits your needs.
Here are some standard garage sizes based on the number of cars you own, as well as an approximate cost for each.
One-Car Detached Garage Prices
A one-car detached garage costs between $9,600 and $16,800 when built with traditional lumber. However, a detached metal garage costs from $6,700 to $8,600, including the foundation.
The standard one-car garage is 12 feet wide by 20 feet deep (12×20), which provides enough room for a sedan, van, or truck to open doors on both sides without hitting the walls.
If you also need room for storage space, a garage with 18×25 dimensions may be a better option. This size will allow several feet of space on the side and back of your garage for storage.
The cost of a detached, 18×25 metal garage starts at about $5,500, but ranges from $9,500 to $12,900 with a concrete foundation.
Two-Car Detached Garage Prices
A standard two-car detached garage is 20×20, with costs ranging from $16,000 to $28,000. However, a garage of that size is pretty tight for larger vehicles. Two-car garage dimensions of at least 24×25 would be ideal, reducing the possibility of scratching or denting the vehicle’s doors when open. It also provides more storage space in the back.
Here are approximate starting costs for two-car prefab metal garages:
| 2-car garage dimensions (ft.) | Starting cost |
|---|---|
| 20×20 | $6,500 |
| 24×25 | $8,000 |
| 24×30 | $9,000 |
Don’t forget to include the cost of a foundation, which will run about $3,500–$6,000 or more for the sizes listed above.
Three-Car Detached Garage Prices
A three-car detached garage costs between $24,000 and $42,000 for a stick-built garage that measures 30×20. A 30×20 metal garage, on the other hand, starts at about $9,000 (plus foundation cost).
Another option is a metal garage with 24×35 dimensions, starting at about $8,600 without the concrete slab. This size of garage gives you the option of having two garage doors on the front or three on the side.
Four-Car Detached Garage Prices
The cost of a four-car 24×45 detached wooden garage will range from $43,200 to $75,600. A prefab metal garage of the same dimensions starts as low as $11,250, plus the cost of the foundation.
As with a three-car garage, this size allows you to choose whether to add bay doors along the side or the end. You could even put doors on both ends for a drive-through garage.
Detached Garage Building Cost Factors
To accurately estimate the cost to build a garage, you must take all materials and labor into account. Here’s an overview of factors to consider.
Foundation
A concrete foundation is crucial for supporting your garage. On average, it costs about $8 per square foot, though the real cost can range anywhere from $5 to $35 per square foot.
The higher cost is due to local labor rates, which differ significantly from place to place. If you know what you’re doing, you can reduce costs by pouring your own foundation. If you take the DIY approach, be sure to follow all safety precautions, local permit requirements, and building codes.
Here are some rough cost estimates for a concrete slab for detached metal garages by size:
| Garage dimensions (ft.) | Approximate cost of concrete slab |
|---|---|
| 12×20 | $2,000+ |
| 18×25 | $4,000+ |
| 20×20 | $3,500+ |
| 24×25 | $5,000+ |
| 24×30 | $6,000+ |
| 24×30 | $6,000+ |
| 24×40 | $8,000+ |
Framing
The cost per square foot of lumber is around $35–$65. On the other hand, steel is a durable and more affordable option, costing around $12–25 per square foot.
Prefab metal construction also cuts down on labor costs. Traditional lumber requires more time and effort to construct, making it a pricier option.
Whichever framing material you choose, make sure to have high-quality framing so your structure lasts a long time.
Electric Wiring
Adding electricity for garage lighting and outlets will cost an additional $1,000 or more. If you plan to use your detached garage as a workspace of any kind, the extra cost will definitely be worth it.
Be sure to hire a certified electrician to install your wiring so you don’t hurt yourself or damage the structure.
Plumbing
Installation costs for plumbing range between $680 and $830 per fixture, according to Homewyse. The actual cost will depend on how far away your detached garage is from your main structure and other factors like insulating the pipe to prevent freezing.
Plumbing is not a common addition to detached garages. However, some people find a sink area helpful for cleaning and handwashing.
Insulation
Insulation costs between $1 and $5 per square foot, depending on which type of insulation you use (batting, blown-in, or spray foam).
If you’ll be spending a lot of time in your detached garage or plan to add heating or an HVAC system, insulation is highly recommended. Insulation can be added to any type of garage, including metal garages.
Roofing
Roof installation can cost around $10,000, depending on the square footage and style.
There are three metal roofing styles available for detached metal garages:
- Regular roof. This is the cheapest roof style, and it opens up the ceiling area, creating extra vertical space.
- Boxed eave roof. This style provides extra protection against wind and weather and offers a cleaner look.
- Vertical roof. This option is the strongest (and most expensive) style. It helps precipitation slide off easily and is required for large metal garages.
Costs of Garage Kits, Prefab Garages, and On-Site Construction
Different methods of construction can affect the costs of a detached garage. Below are three different construction types to consider.
Garage Kits
Garage kit costs range from $3,000 to $15,000, including delivery.
As the name suggests, garage kits arrive in parts and come with assembly plans for the homeowner or installer to put together. Garage kits usually cannot be customized, as their pieces are mass produced.
Prefab
Prefabricated or “prefab” detached garages start at about $4,200, with metal garage prices increasing by size, features, and customizations. They are cost-effective alternatives to traditional detached garages made of lumber.
Prefab garages have their critical framework prebuilt in a factory, which is then delivered to the customer. They often can be assembled and installed in a single day.
On-Site
Traditional on-site construction of detached garages can cost as much as $28,000 or more.
Sometimes referred to as “stick-built,” on-site detached garages are the most expensive option. The overall price factors in all materials, tools, labor, installation, and any additional customizations.
Hiring a local garage builder is much more expensive than having a prefabricated metal garage installed, which eliminates the cost for extra material and labor. If you’re on a budget, prefab metal garages are a great and durable alternative.
Try Our Garage Cost Estimator
Before starting your detached garage project, check out our Metal Garage Buyer’s Guide. It has plenty of helpful ideas and tips on choosing the best option.
When you’re ready to purchase, you can use our dual customization and cost estimation tool below to design your dream garage and calculate the project costs.
FAQs About Detached Garage Costs
Still have questions about detached garage costs? Get answers to some of the most popular questions below.
What’s the average cost to build a detached garage?
The average cost for a detached garage varies greatly depending on the size, construction style, materials used, and other features. A one-car garage may start around $18,000, while a three-car garage may cost over $70,000 for traditional construction. However, prefabricated metal garages can cost half as much or less.
Do detached garages require a permit, and how much does it cost?
Detached garages may require a permit depending on where you live. Permit costs and requirements can differ from city to city and state to state, so be sure to check with your local city or town building authority to see if you need a permit to build a separate structure on your property.
Is it cheaper to build a detached garage?
On average, attached garages can be a little cheaper to build, especially when built at the same time as the home (rather than as a later attachment). However, detached garages may have less expensive materials and customization options that bring the overall cost down. You can use our 3D garage builder to find an inexpensive option that works for you.
Are there less expensive alternatives to a detached garage?
If you don’t need a full detached garage, a garage alternative like a metal carport or shed might be a more affordable option for you.
