How much does it cost to build a garage?

An attached garage makes your home functional and your lifestyle easier. Having an attached garage means that you can enter and leave your car without going out into the elements. Building an attached garage has many more considerations, however, than a detached model. It also has different cost factors, which are impacted by things like size, style, interior finishing, and external siding. 

Building an attached garage costs on average $22,000 to $43,000, with the average homeowner spending around $35,000 on a 24 x 24-foot, two-car garage with vinyl ¹ siding, asphalt ² roof, and unfinished interior.

Attached garage costs

Size

Technically, you could have your new attached garage built in any size you desire, but there are a few standard sizes. For a one-car garage, the average size is about 12 x 20 feet and has an average cost of around $18,000. The smallest size you can use for a two-car garage is approximately 20 x 20 feet, with an average price of $28,000. Most people find that 24 x 24 feet ($30,000 to $35,000) is more comfortable for two cars, provided you have the room.

Excavation and site prep

Like any build, the construction area must first be cleared and prepped. This varies depending on the condition of the lot beside your home. If it is level and cleared, the excavation will be less invasive than if you need to clear and level the lot. Typically, excavation for a garage simply involves clearing the site of any landscaping and ensuring a level area for the foundation. This cost ranges from as low as $500 for a simple leveling ³ to $2,500 if you need to remove some landscaping first. 

An attached garage needs access to your home. So, the project may have demolition costs, depending on whether your garage will be minimally attached or open fully into your home’s interior. These costs range from $200 to $5,000, depending on how much your current exterior needs to be altered.

Foundation

Most garages have a slab foundation ⁴ that doubles as the floor of the garage and costs around $4 a square foot. If you require heavier footings ⁵ like for supporting a living space above the garage, then your costs can rise to $5 a square foot. For a 24 x 24-foot garage, expect the foundation to cost approximately $2,300 for a basic slab.

Walls

After framing your garage, consider how the inside walls will be finished. Some people leave them unfinished and uninsulated because the garage is only used for storage. Others choose to insulate the walls or cover them with drywall ⁶. Doing so can make your garage more comfortable and provide more choices later for how you use the space, such as enabling you to install shelving, workspaces, and other options. 

Basic drywall ⁶ for an interior costs around $1,500 to $2,000, while insulation for new construction costs about $1,500, assuming fiberglass ⁷ batt insulation.

Siding

The exterior of your garage walls also needs finishing. Because the garage is attached to the rest of your home, it is typical to use the same siding and trim material you have on the rest of your home to finish the garage. This produces the most cohesive look for the property and makes the garage look like it was built with the house, rather than as an add-on. This also means that any finish techniques, decorative trim, or accent material needs to be included on the garage’s facade as well. 

Typical materials and costs for siding and trim for a garage include:

• Aluminum - $3.50 to $4.75/sq.ft.
• Fiber cement ⁸ - $4/sq.ft.
• Vinyl ¹ - $5/sq.ft.
• Stucco - $7/sq.ft.
• Wood - $7 to $10/sq.ft.

Garage roof

Like the siding, your garage should ideally have the same roof as the rest of your home. This is especially important if your garage will have the same height as the rest of the property because the roofs are often joined for a seamless appearance. Switching materials suddenly at the garage can lower the curb appeal of the property. 

The most common material installed on most homes is asphalt shingle, which costs around $80 to $100 per 100 square feet.

Utilities

Attached garages have the benefit of being able to be wired with the home’s electricity, heating, and even plumbing if you desire. Most garages only include electrical work, however, which provides for wiring the garage door opener, installing lights, and at least one electrical outlet. It is possible to make your new attached garage into a full workroom, which would mean adding other utilities. Keep in mind that when you pull a permit for the new garage, each utility you add may require a separate permit, depending on the area where you live. So while you need a building permit and an electrical permit for most garages, you may also need a plumbing permit if you plan on having water in your garage. You will pay between $65 and $85 an hour for an electrician when building your garage and expect the wiring to take anywhere from 4 to 16 hours, depending on the scope of the job, for a total of $260 to $1,360 in electrical work.

Flooring

Most garages have a concrete slab foundation, which doubles as the floor. Seal this floor or coat it in epoxy to help it last longer, at a rate of around $500. If you plan on parking your car in the garage, you may want to leave the flooring at that. However, if you plan on using it for other things, there are garage floor systems that create a rubberized, more comfortable floor. They start at approximately $3,000.

Garage door

Garage doors are an integral part of a new attached garage. While there are double garage doors, which uncover both cars at once, it is more common to have one door for each vehicle stored in the garage so that each has its own access. 

Garage doors come in several materials, each of which has attributes to consider:

Garage door opener

Even lightweight garage doors are heavy and cumbersome to operate. So, most people invest in a garage door opener or automatic system that raises and lowers the door for you. The price of a garage door opener varies depending on the model, but most cost between $300 and $350 installed.

Building process

The building process for an attached garage differs depending on the project size and scope, your home’s style, location, and finishing work. But most are constructed similarly. 

The ground is cleared and leveled so that the concrete pad can be poured. A frame is laid, and the walls and roof are erected. At some point, an opening is cut into the existing home to connect it to the garage. There may be changes to the exterior of the house where it meets the garage, such as the removal of siding.

The interior walls are finished as much as desired. This may include installing insulation and drywall or leaving them bare. Shelving may be installed, the electrical work is completed, and the floor is sealed or finished as desired.

The exterior of the garage is clad to match the rest of the home, and new trim may be installed where the new garage meets the existing house to make the transition look better. If there is no driveway currently, one will be constructed, and the new garage doors will be installed and hooked up. Any windows will also be installed, and the exterior and roof finished. 

A new interior door will likely be installed from the garage to the home.

Labor costs

Labor costs vary depending on the scope of the project and what phase it is in. An electrician’s fees differ from a contractor’s fees, for example, but on average, most people find that they spend around $20 to $30 a square foot on labor. This makes the price about $15,000 in labor out of the $35,000 total.

Attached vs detached garage

An attached garage is not the only choice you have for storing your car. Detached garages are also a valid choice. When making the comparison between the two, most people like that an attached garage offers the convenience of not having to go outside to get to their car in inclement weather. However, detached garages are often considered safer because there is no exhaust or fumes that could enter your living area. Detached garages can also usually be expanded if there is space, while it may be more difficult to expand an attached garage without upsetting the footprint of the home. Detached garages also give you more options to place the garage on your property and may work better for odd-sized lots. Attached garages may make the most of a small space. Both provide storage and improve the value and function of your property.

Enhancement and improvement costs

Garage Organizer System

If you plan to use your garage for more than storing your car, you may want to invest in a garage organizer system for around $2,610 on average, which helps make the most of the space.

Battery Backup

Garage doors run on electricity. If the power goes out, you may find that you cannot open or close your garage door. A backup battery system can help, and they start at around $100 additional for the opener.

Exterior Lighting

If you plan to come and go from the garage a lot, you may want to invest in exterior lighting for the area. This helps make the space safer and easier to navigate. Expect to pay around $3,500 to $4,500 on exterior lighting.

Gutters

Your new garage should have the same gutters as the rest of your home to direct rainwater away from the structure. Without them, you could have softening or rotting of areas like the soffit and fascia. New gutters cost around $1,050 to $2,400 installed.

Insulation

Not all garages are insulated, but if you plan on using the space for more than your car, you may want to insulate it now. Insulating during construction only costs $0.50 a square foot for fiberglass batts.

Windows and Skylights

Not all garages require windows or natural light, but if you plan on spending time there, you may want to have some installed. New casement windows cost around $1,480, while a skylight costs between $450 and $1,500.

HVAC

If you plan to spend time in your garage, you may want to add an all-in-one heating and cooling unit for between $700 and $1,500. It is inadvisable to run ducts through your garage due to health risks from the fumes, so all-inclusive garage units are the best choice.

Door into the House

You will need to install a door between your garage and home. Entry doors cost between $500 and $700 on average.

Workshop Area

Garages can be used for many things, including workspaces. If you plan on using yours for this purpose, you may want to install shelving ($100 to $500), countertops ($500 to $3,000), cabinetry ($500 to $5,000), or other items that make the space more usable.

Second Driveway

You may need to pave a new or additional driveway to your garage to access it more easily. An asphalt driveway costs around $830 on average to pave.

Additional considerations and costs

• Adding a garage to your property typically has a return on investment of 60% to 80%.
• An attached garage may be a security threat because intruders can access your home through the attached door. Ensure that the entryway is a secure door to help prevent this.
• If your workplace uses flammable items in the garage, keep in mind that there is a danger of fire for not only the garage but your entire home. This risk is lowered for detached garages.
• The American Lung Association recommends using ventilation in attached garages where chemicals may be used or stored, as well as to avoid idling cars to prevent exhaust from entering the home.
• Permits are required for the building of a garage and depending on the type and scope of work, you may need several permits. Check with your town or city hall for more information.

Remodeling Terms Cheat Sheet

¹ Vinyl: A synthetic plastic made from ethylene and chlorine. Vinyl has many applications in the construction industry and it is widely used in sidings, window frames, roofing and gutters, among others

² Asphalt: A viscous, black mixture of hydrocarbons often used for roofing and waterproofing. It is also used in asphalt for paving roads

⁴ Slab foundation: A layer of concrete, poured over a prepared surface of soil or gravel, that supports a house or other building structure

⁵ Footings: A support for the foundation of a house that also helps prevent settling. It is typically made of concrete reinforced with rebar, but can also be made of masonry or brick. It is usually built under a heavier part of the house like a wall or column, to distribute the weight of the house over a larger area.

⁶ Drywall: Type of plasterboard, commonly used to build walls and ceilings, composed of gypsum that is layered between sheets of heavy paper

⁷ Fiberglass: Plastic that is reinforced with glass fibers. The fibers may be mixed randomly throughout the plastic, or come in the form of a flat sheet, or be woven into a fabric

⁸ Fiber cement: A building material made with cellulose fiber, concrete, and recycled materials such as glass