How Much Does a Home Addition Cost? [2025 Data]

Home Addition Cost by Square Foot

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:

Cost of a Home Addition Cost by Room Type

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. 

Bedroom

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.

Bathroom

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.

Living or Family Room

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.

Kitchen

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.

Mudroom

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.

Finished Attic

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.

Finished Basement

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. 

Sunroom

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. 

Detached Garage, Shed, or Outbuilding

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.

In-Law Suite

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. 

Front Porch

Adding a front porch to your home costs $4,600 to $22,200, on average. 

Second-Story Addition

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.

Bump-Out

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.

General Contractor Costs

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.

Architect Costs

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.

Other Pros to Consider Hiring

Depending on the scope of your project, bringing your home addition ideas into reality will require the skills of several subcontractors. If you hire a contractor to build your addition, these services will be included in your total project cost. If you manage the project yourself, you'll need to hire the ones you need along the way. In either case, here's what to expect in terms of subcontractor costs.

Cost of a Home Addition by Location

Your home's geographic location will affect the cost of your home addition project. Expect costs to reflect the price of living in your area. For example, for those living in rural areas or where the cost of living is low to moderate, labor costs will be relatively low as well. 

Additional Home Addition Cost Factors

In addition to the costs for labor and materials, other price-altering items will come into play for your home addition project. While the costs and management of these items will be part of your project agreement and price estimate, it's essential to discuss them when hiring a local home addition contractor. 

Permits

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.

Materials

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:

For more details about each type of home addition material, check out the following:

• Foundation material cost

• Home insulation cost

• Exterior door cost

• Interior door cost

• Drywall installation cost

• Electrical cost

• Plumbing cost

• Roofing cost

• Flooring cost

• Painting cost

Site Prep

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. 

Building a Home Addition Yourself vs. Hiring a Pro

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.

How to Save on House Addition Costs 

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.

Financing a Home Addition

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.

Does an Addition Increase Home Value?

Several home remodeling projects can yield a high return on investment (ROI), some in excess of 100%. However, constructing a home addition will have an ROI that depends heavily on the type of addition you build and the project's cost. You can expect a return toward the value of your home of between 50% and 60% for most additions. If you can save money during the project, you could see up to 80%.

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’ve surveyed thousands of real Angi customers about their project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We pair this data with research from 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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