The average U.S. homeowner spends about $51,043 on a home addition. Depending on the location, size, type, and materials, most spend between $4,000 and $160,000.
The average home addition cost is $51,043 but the price can vary from $4,000 to $160,000. With the proper home renovation contract, a home addition will no doubt add value to any home—and allow you to entertain guests and enjoy your space to the fullest. Home addition ideas come in many different sizes and types, from outdoor sheds to primary suites and everything in between. Take a look at the average home addition cost and the various cost factors to consider before jumping into this home improvement project.
Home addition costs can vary greatly based on the size and scope of your project, who you hire, and the permits and materials you need to complete the job. While it can seem daunting at first, hiring a home improvement contractor can take some of the burden off your shoulders and ensure you’re getting the job done right.
While you may have your heart set on a large home addition, the bigger it is, the more expensive it will be, so you’ll want to factor that into your budget. In general, home additions cost between $80 and $210 per square foot, though the number will depend on the complexity of the room and its finishes. For example, a bedroom will cost between $80 and $160 per square foot, whereas the cost of a bathroom remodel ranges from $70 to $250 per square foot.
Be sure to include other costs as well, such as laying a new foundation (which costs about $75 per yard), along with insulation, site preparation (if extending the perimeter of a house, excavation costs $2,560 on average), and electrical wiring.
Let's look at a few examples of home addition sizes based on the room and design:
| Room Type | Room Size by Feet | Average Cost Range for a Home Addition |
|---|---|---|
| Half Bathroom | 6 x 10 | $4,200 – $15,000 |
| Guest Bedroom | 10 x 10 | $8,000 – $21,000 |
| Full Bathroom | 10 x 12 | $8,400 – $30,000 |
| Kitchen | 10 x 10 | $10,000 – $30,000 |
| Primary Bedroom | 14 x 14 | $15,700 – $41,200 |
| Living/Family Room | 12 x 18 | $17,300 – $43,200 |
Building a home addition is a difficult task, so you want to ensure it’s done correctly. Avoid wasting time and money (and the potential need for a rebuild if something goes awry), and ask a home addition contractor near you for an estimate. General contractors oversee and manage the full scope of a project and charge about 10% to 20% of your total project cost. Ideally, ask multiple contractors for bids to understand the full scope of your options.
Some contractors offer free estimates, but if your project requires substantial consulting or design work, you may need to factor in an extra $150 to $1,000 to cover the expense of the consultation.
An architect is not required, but hiring one can optimize the design and use of your new space. A local architect charges between 5% and 20% of the total project cost.
The permits you need for a home addition may include structural, electrical, plumbing, gas, and other local ones outlined by your municipality. The average cost of a building permit is $1,300, but it can cost as little as $150 in rural areas or as much as $7,500 in some cities.
As you can imagine, it takes many kinds of building materials to complete a custom home addition. Common building materials you’ll need to complete a room addition include the following:
| Home Addition Material | Average Cost |
|---|---|
| Foundation | $5 – $37 per sq. ft. |
| Framing Lumber | $5 per standard 4 x 4 |
| Insulation | $0.20 – $2 per sq. ft. |
| Window | $250 – $1,000 each |
| Exterior Door | $500 – $2,000 each |
| Interior Door | $250 – $1,150 each |
| Drywall | $1.50 per sq. ft. |
| Electrical Work | $50 – $100 per hour |
| Plumbing | $600 – $1,600 total |
| Roofing | $120 – $400 per roofing square |
| Siding and Trim | $1 – $30 per sq. ft. |
| Flooring | $2 – $22 per sq. ft. |
| Paint | $100 – $530 |
For more details about each type of home addition material, check out the following:
Some demolition and land excavation may be necessary to prepare your site for the new addition. On average, site prep for a home addition costs between $1,500 and $5,000, but if you’re adding a second floor or installing a basement, costs could go up to $10,000.
Skilled laborers and tradespeople ensure your home addition idea is beautiful and well-built. Depending on the type of addition, you may need to hire the following pros:
| Contractor Type | Average Cost Range per Hour |
|---|---|
| Painter | $20 – $50 |
| Roofer | $40 – $80 |
| Electrician | $40 – $100 |
| HVAC Technician | $50 – $100 |
| Plumber | $50 – $200 |
| Carpenter | $75 – $100 |
| Structural Engineer | $100 – $200 |
The cost to add on a room varies based on the type and size of the room you’re building. When you’re looking to add a room, you can choose to build out or up. If you build out, the cost averages $80 to $200 per square foot, while second-story rooms run $100 to $300 per square foot.
Adding a 9-by-12-foot bedroom costs $8,600 to $21,600. However, a full primary bedroom suite with a bathroom can cost over $100,000.
The cost to add a bathroom falls between $6,200 and $15,500. The bathroom’s size and any new plumbing and electrical wiring will greatly influence the price.
An 18-by-12-foot living room add-on costs $17,300 to $43,200 but also depends on any new HVAC and electrical needs.
The cost of a kitchen addition ranges from $100 to $300 per square foot. However, you’ll need to budget for any new electrical wiring, which averages $1,180.
Adding a mudroom, which includes an exterior door, waterproof flooring, and a window, costs $8,000 to $18,000 for a 50-square-foot space.
The price to finish an attic ranges between $4,600 and $16,000, depending on the existing structure. Adding a room above a garage costs around $24,000.
Finishing a basement costs $2,800 to $34,500, depending on the extent of the design. Adding a finished laundry room will cost far less than adding an entertainment space, wet bar, and bathroom. Projects include additional plumbing, insulation, flooring, and drywall.
The cost of adding a sunroom is $20,800 to $72,600, but building a large, luxury sunroom can run as much as $140,000. A three-season sunroom costs $10,000 to $40,000 and is a less-insulated version of a four-season sunroom, which costs between $25,000 and $80,000.
The cost of a shed averages $2,500 without electricity or heat. A full guesthouse averages $24,700. You’ll need to enlist the help of a general contractor and a local electrician for a detached addition.
Rates vary widely for in-law suite home additions. A simple bedroom unit costs around $8,600 to $21,600, while it can be as much as $100,000 for a full unattached suite.
Adding a front porch to your home costs $4,600 to $22,200, on average.
The average cost of a second-story addition is $100,000 to $250,000 but can cost as much as $600,000 or more. A local structural engineer can help assess if your home and foundation can support a second story.
A bump-out extension costs $4,000 to $30,000, depending on its location, size, finishes, and fixtures. Designers use bump-outs for many of the rooms listed above, such as extra space for a sunroom or to create a breakfast nook in your kitchen.
Labor fees make up 30% to 50% of home addition costs, but you can save money by handling simple parts of the project yourself. Some suitable DIY tasks include hanging drywall, laying flooring, installing cabinetry, and painting.
However, building a home addition is a complicated job you shouldn’t tackle entirely on your own. A local general contractor is the best pro to oversee a home addition. Most homeowners also consult an architect to ensure the design matches the rest of the house and a structural engineer to ensure safe construction. Often, you’ll also need to hire an electrician, plumber near you, or other contractors to make sure you build your home addition is up to code.
Many home improvement projects can go over estimate, usually anywhere from 5% to 20% of the project quote. But you can still save on the cost of your home addition without sacrificing quality by following these tips:
Choose standard finishes, such as vinyl plank flooring.
Opt for a simple home addition floor plan with standard height ceilings.
Complete some tasks yourself, such as painting the family room or installing light fixtures.
Compare bids from at least three general contractors to ensure the best value.
Research whether you qualify for tax credits or refunds. Sometimes, home additions are considered capital improvements with energy-efficient designs.
When financing a home addition, you have a range of loan options depending on your financial situation. These include:
HELOC loans: Ideal for homeowners who can borrow the amount against the equity on their home
Personal loans: Have a quick approval process for unexpected home extension costs that pop up during the process, but may have higher interest rates
Credit cards: Often ideal for small extension costs, such as minor refinishing upgrades, because of higher interest rates than loans
Refinance loans: Lengthy approval process c
As with all these loan options, always speak with a financial advisor before refinancing your home for home projects.
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Yes, a home addition will absolutely add value to your home, particularly when you extend your home's square footage. In fact, you’ll likely see a drastic increase in your home valuation for adding a room. There are several projects that have high return on investment (ROI) value, including adding a primary suite with a ROI of 55%.
While it’s never too early to start planning for a major home renovation like this, give yourself at least a couple of months to plan and design your addition, find a contractor, and get the permits in order. Then, plan for another two to three months to complete the home addition itself.
It’s less expensive to build up than add on. Building up involves adding a room to the second story of a house without increasing the home’s footprint. However, a contractor may need to strengthen the existing foundation to support the added weight. Building out involves adding a room on the ground floor of a house, and it’s one of the most popular additions performed by local home construction companies, as it might involve the construction of a new foundation or acquiring a zoning license to expand.
