How Much Does It Cost to Add a Room Above Your Garage? [2025 Data]

The average cost to add a room above a garage is $50,000. You’ll pay just $10,000 to add general living space over a single-car garage or as much as $270,000 to build over a three-car garage with a kitchen and bathroom to create a separate living area. The cost per square foot for the conversion is between $100 and $300.

Type of Room

The type of room above your garage you add will have a significant impact on your overall price. Open living space or an added bedroom that just requires a connection to your heating, cooling, and electrical systems and doesn’t require any special installations will be the most affordable. You can also opt to install an in-law suite or attached ADU, but adding a kitchen and a bathroom can triple your per-square-foot costs.

Size of Room

Building an over-the-garage addition can cost between $100 and $300 per square foot, so the size of your garage room addition plays another important part in the price tag for this project. The average garage size ranges from 240 to 704 square feet, depending on how many cars it holds. You can get an idea of the cost to add a room above your garage based on your garage size using the table below.

Home Addition Contractor Costs

Between 40% and 60% of your total will go toward labor, and nearly all of that will go to a local home addition contractor. This pro may use in-house specialized contractors like plumbers, electricians, and HVAC techs to handle utilities, and they’ll tackle the construction and finishing themselves. Below are some of the common tasks a home addition contractor will handle, along with average costs.

• Framing the add-on: $4–$16 per sq. ft.

• Installing the roof: $4–$11 per sq. ft.

• Installing siding: $1–$13.50 per sq. ft.

HVAC Costs

If you envision your new room above your garage as a living space, you’ll need a way to heat and cool your addition. Your home addition contractor will often have an HVAC tech on staff, but if you instead choose to hire individual professionals for each portion of the job, you’ll need to coordinate with a local HVAC pro. Depending on what systems you choose, you can expect to pay anywhere from $2,000 to $14,500 for HVAC.

• Ductwork installation: $300–$2,100

• Installing a ductless mini-split: $2,000–$14,500

• Installing a standalone central AC unit: $3,000–$8,000

Electrician Costs 

Similarly, you’ll need to hire an electrician to extend your existing electrical system up into the room above your garage. Hiring an electrician costs an average of $50 to $130 per hour, but you could see a flat fee of between $500 and $1,500 for this project. Some projects for your above-garage room include the following.

• Installing an outlet: $100–$450

• Adding a light fixture: $150–$1,000

• Installing a light switch: $100–$200

Additional Contractors to Consider Hiring

Depending on the type of room you’re planning to build over your garage, you may need to hire several other contractors to get the project done.

• Architect cost: $2,400–$14,000

• Cost to install insulation: $40 to $80 per hour

• Drywall installer cost: $1,000 to $3,200

• Flooring installer cost: $2 to $25 per sq. ft.

• Insulation installation cost: $0.30–$6.75 per sq. ft.

• Interior painter cost: $2 to $6 per sq. ft.

• Plumber: $45 to $200 per hour

• Structural engineer cost: $350–$800

• Window installer cost: $300 to $2,500 per window

Additional Cost Factors

There are some additional costs you may encounter when adding a room above a garage. The home addition company that you hire should include most of them in your contract.

Permits 

You’ll need a building permit to add a room above your garage. Depending on your location and local requirements, you can expect to pay anywhere from $140 to $2,500 for a general construction permit, which should cover the plumbing, HVAC, electrical, and roofing work that might otherwise need separate permits. If you’re building the addition as an attached ADU and plan to rent it, you’ll also need a rental permit.

Foundation Strengthening

In some cases, an existing garage foundation may need to be strengthened to support the weight of a new room above it. Pros will often do this by extending your foundation's depth, repairing damaged areas of your foundation, or adding additional support through methods like underpinning. Foundation strengthening can add $2,000 to $10,000 to the overall cost of your project.

Post-Construction Inspection

Any inspections that your building department requires will be included in your permit fees, but it’s a good idea to have a post-construction inspection done after the project to ensure the structure is safe. A home inspection costs between $300 and $450.

Post-Construction Cleanup

After a large construction project comes the inevitable cleanup. Excess drywall, flooring pieces, dust, and debris all need to go before you can enjoy your new space. Your contractor should include the cost for cleanup within your contract, but budget an additional $200 to $500 if they don’t.

Adding a Room Above Garage vs. Detached Addition

Adding a room above a garage costs less than building a detached addition in most cases. Building up from your existing garage means you can skip the foundation, which saves you thousands on the cost. You’ll pay an average of $50,000 to add a room above your garage, whereas building a detached ADU or tiny home addition will cost an average of $180,000.

However, you should think about more than just the cost when deciding. If you’re renting the added space or saving it for long-term guests, building over an attached garage will give you and your guests less privacy than you’d get from a detached ADU. You’re also more limited in the square footage you can add above a garage, while an ADU gives you more freedom to customize.

DIY Garage Addition vs. Hiring a Pro

Building a room above a garage is not a DIYable project, so you should leave this one to a professional who builds home additions. Building a garage requires specialized skills and knowledge in architecture, structural engineering, electrical work, and plumbing. It also involves intricate tasks like pouring concrete foundations, framing walls, installing roofing systems, and connecting utilities, most of which your building department won’t let you do yourself legally.

However, you can DIY some finishing touches to save money on labor. Consider installing and painting the drywall yourself or installing flooring, which are more DIY-friendly projects associated with building a room above a garage. 

How to Save Money on Your Room Above Garage

While it can seem financially overwhelming at first, there are a few things you can do to help lower the cost of adding a room above your garage.

• Compare quotes from at least three different home addition companies to find the right pro for your job. 

• Consider what you’ll use the space for, and if possible, avoid additional costs like plumbing.

• Take on some of the DIY-friendly portions of the overall project, like interior painting.  

Does a Room Above a Garage Increase Home Value?

An above-garage addition can boost your property value with an ROI ranging from 60% to 80%, with an average of 69%. This is due to the increase in livable square footage and the added value from an additional bedroom, which future home buyers will undoubtedly enjoy. The bump you’ll see depends on the type of space you install.

How Angi Gets Its Cost Data

Home is the most important place on earth, which is why Angi has helped more than 150 million homeowners transform their houses into homes they adore. To help homeowners with their next project, Angi provides readers with the most accurate cost data and upholds strict editorial standards. We extensively research project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We rely on reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects. 

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