How Much Does a Garage Extension Cost? [2025 Data]

If you’re adding more space to your existing garage, you can expect a garage extension cost of around $10,000, with prices commonly ranging from $3,500 to $14,000. Some custom projects can cost $33,800 or more.

Building a garage extension is an excellent way to give yourself more space for work, recreation, or storing your belongings. To ensure you build an area that suits your specific needs, it's important to understand garage extension cost factors. 

How Much Does It Cost to Extend a Garage per Square Foot?

On average, a garage extension costs $40 to $70 per square foot. If your project requires knocking down an exterior wall, your expenses will be on the higher side. Extending a garage often costs less than building a new garage, and it’s more comparable to the cost of remodeling a garage. 

Here are some common garage sizes and configurations, including what you might pay for materials and labor:

Garage Extension Cost Breakdown

To extend a garage, you can divide project costs into three buckets: preparation, demolition, and building.

Design

As garage extensions involve new construction, you should hire a structural engineer. They will review your design plans and draw up blueprints that follow local building codes and other requirements. The cost of hiring a structural engineer is 1% to 20% of your construction budget, which translates to $200 to $1,500 for a build of easy to medium complexity.

Permits

Many municipalities require construction permits when you renovate your home. These pay for records of your improvements in official documents and inspections to ensure soundness. Depending on your location, permitting may cost $200 to $1,500.

Demolition

Demolition might be necessary in some cases, like when adding onto your garage width-wise, because you'll need to knock down part of an exterior wall to build outwards. 

The cost to remove a wall ranges from $1,000 to $10,000, and it largely depends on whether the wall is load-bearing. Aside from the complexity of working with load-bearing walls, there may also be plumbing and electrical concerns, so it's always best to leave this type of work to a professional.

General Contractor

If you don't plan to manage the construction of your garage extension, you'll need to hire a local contractor to oversee the project. You'll pay this professional about 10% to 20% of the overall project cost. Most contractors charge between $50 to $150 per hour.

Foundation

The cost of building a foundation for your garage extension often ranges from $5 to $18 per square foot, depending on the type you need. A monolithic concrete slab usually works, but local conditions could require a stem wall slab or pier and beam construction instead.

Framing

Framing involves building out the new skeleton for your garage addition. When you hire a local framer, you’ll often pay $7 to $16 per square foot. The cost depends on whether you choose lumbar or steel, the square footage, and other factors. 

Electrical

With new square footage in your garage addition, you'll likely need more electrical outlets for power tools and other accessories. You may also need wiring throughout the walls and ceiling for light fixtures, garage doors, and alarms. The average cost to hire an electrician is $50 to $100 per hour.

Plumbing

A garage addition may have ample room for a new washtub or even your laundry machines. Also, since an exterior wall may have been demolished or moved, you might need a new spigot for a hose. The cost to hire a plumber to add new piping and fixtures runs from $45 to $200 per hour.

Roofing

The cost of roofing your garage can range from $1,000 to $3,000. The price depends on whether your contractor can add on to your existing roofline or if they need to remove the old roof and build a new one.

Garage Door

One of the final steps of extending a garage is adding a new garage door or replacing your existing one with something larger. This may be necessary if you build your garage wider or extend the front, but you might not need it if your construction took place at the back of the garage. 

The cost for garage door installation runs from $750 to $3,000, depending on the specifics. The local garage builder you hire often handles this step of the project. However, the builder may subcontract the work. 

Exterior Siding

Once the garage is built, it's time to turn your attention to finishing it. In most cases, your existing home finish will determine what you'll choose for the garage. For example, if your house has a stucco exterior, you'll likely use that for your garage too. The same applies if you have cedar or vinyl siding. 

Assuming you have a stucco exterior and drywall or cinder block interior, at the very least you'll need to pay for painting. If you hire a pro, expect to pay $1 to $6 per square foot to paint the interior and exterior.

Garage Extension Finishing Costs

Naturally, if you want to finish the garage addition, you’ll need to budget for these costs. Here are some common add-ons:

• Garage insulation cost: $1,900–$7,700

• Cost to drywall a garage: $360–$1,700

• Cost to add an entry door: $546–$2,375

• Cost to completely finish a garage: $6,020–$27,705

• Garage floor replacement cost: $2,400–$11,200

Extending a Garage Yourself vs. Hiring a Pro

On average, it costs $40 to $70 per square foot to extend a garage. Labor alone makes up 50% to 70% of the finished project cost, meaning you save $20 to $50 per square foot if you do a DIY renovation.

To break this down further, consider a garage extension of 200 square feet, which is equivalent to extending a two-car garage to hold three cars. If you pay a professional to do the job, you'll spend $8,000 to $14,000 in material and labor costs. However, if you complete the project on your own, you could spend as little as $4,000 just for materials. 

There's no doubt that completing a garage extension on your own can result in significant savings, but just looking at numbers doesn't offer a real appreciation for the hard work that goes into the construction project. Extending your garage requires significant skill as you'll be dealing with load-bearing walls, electrical, and general construction. Also, doing a building project wrong can present a significant danger to yourself and anyone who enters your home.

Unless you're a pro, extending your garage is a job better left to those who are more qualified.

Tips to Reduce Costs While Extending a Garage

There’s no getting around it: the cost to add a garage to the side of the house or to extend an existing garage can be expensive. Here are some tips to keep prices down:

• Limit the project scope: If you currently have a one-car garage, it will be much more affordable to extend it to a two-car garage rather than a three-car garage.

• Avoid extras: If your garage does not currently have plumbing, you’ll need to hire a plumber to set up appliances like a washer, dryer, or utility sink. A local HVAC specialist might also be needed to extend ductwork into the garage or install a separate heating system. You’d also have to insulate a garage with plumbing and heating—and this would drive up the price even further. Consider skipping these additions altogether to save money. 

• Do parts of the project yourself: Extending your garage is a challenging project, and one that absolutely requires professional contractors. You can cut costs by doing some of the easier work yourself, such as drywalling, installing the garage door opener, and, if you’re a more experienced DIYer, adding the exterior siding yourself. You may also be able to handle the demo, junk removal, and insulation—here’s how to insulate your garage on your own.

• Get multiple quotes: As with any major construction project, we recommend getting quotes from at least three contractors. Assuming all the contractors have strong reviews, proper certifications and experience, and similar timelines, you can hire the one with the lowest bid.

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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