How Much Does a Home Addition Cost?

Typical Range:

$20,748 - $73,129

Find out how much your project will cost.

Cost data is based on actual project costs as reported by 4,718 HomeAdvisor members. Embed this data

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  • Homeowners use HomeAdvisor to find pros for home projects.
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Updated April 4, 2022

Reviewed by Ezra Laniado, Expert Contributor.

Written by HomeAdvisor.

The cost of a home addition typically ranges from $20,748 and $73,129 but varies depending on many factors, from the size and type of the addition to the materials used. The average addition costs about $80 to $200 per square foot, for a total of $46,000, with smaller projects costing around $20,800 and more complex projects costing around $72,500. Some home additions with more square footage and/or customizations can cost more than $150,000.

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National Average $46,772
Typical Range $20,748 - $73,129
Low End - High End $5,000 - $145,000

Cost data is based on actual project costs as reported by 4,718 HomeAdvisor members.

Home Addition Prices

There’s a wide range for how much a home addition costs because material prices vary greatly. You’ll need interior materials, like floors and paint, plus exterior materials to match the addition to the rest of the home.

Foundation$4 – $25 per square foot
Flooring$0.50 – $15 per square foot
Roofing$75 – $600 per square foot
Paint$2 – $5 per square foot
Support Beams$1,150 – $4,600
Drywall$1 – $3 per square foot
Insulation$2 per square foot
Siding and Trim$1 – $30 per square foot
Interior Doors$250 – $1,150 each
Exterior Doors$500 – $2,000 each
Windows$250 – $1,000 each

Home Addition Installation Costs

There are many parts to consider in a home addition. You may require design services, an electrician, and a plumber, plus contractors for demolition and construction. Reserve anywhere from 30% to 50% of your project budget for installation costs.

Home Addition Installation ProfessionalCost
Architect$2,000 – $10,000
Demolition$500 – $10,000
Roofer$2 – $5 per square foot
Electrician$40 – $100 per hour
Plumber$50 – $200 per hour
Carpenter$75 – $100 per hour
General Contractor$100 – $150 per hour
HVAC Technician$50 – $100 per hour

Home Addition Cost by Type of Room

Different rooms may require different materials or components, making rooms with plumbing, like kitchens, more expensive to add compared to the cost to add a master bedroom or sunroom.


Converting an attic into a livable space costs about $40,000 to $50,000. This conversion needs to have enough insulation and ventilation for comfortable year-round use. Plus, remember to account for the cost of installing a safe stairway into this room.


A bathroom of around 50 square feet will cost an average of $25,000, while adding a more luxurious and larger bathroom of 100 square feet will cost about $75,000. Bathrooms are a more expensive addition because they require plumbing, plus fixtures like showers and toilets.


A bedroom home addition typically costs around $50,000, but if you are planning to add an en suite bedroom, expect to spend $100,000 or more.

Dining Room

A standard dining room is about 14 feet by 16 feet, and this costs about $20,000 to $45,000 to add to your home. Expect to pay more if you plan to add a wet bar or built-in cabinets and shelves.


Expect to spend $50,000 to $100,000 for 200 square feet of added kitchen space. Kitchens are one of the most expensive home additions because they require electrical work, plumbing, and appliances.

Laundry Room

The cost of a 35-square-foot laundry room is about $5,000 to $7,000, including the cost of newer appliances, additional storage, and waterproof flooring.

Living Room

You’ll spend about $20,000 to $45,000 for a 12-by-18-foot living or family room. The cost will increase for larger rooms with high-end finishes and custom entertainment centers.

Mudrooms and Sunrooms

Mudrooms and sunrooms typically cost around $8,000 to $12,000. These are popular additions for added storage and living space. A 50-square-foot mudroom, including storage and built-in organization systems, costs around $12,000. For a sunroom, expect to spend $8,000 to $11,000 for something simple or upward of $80,000 for a 200-square-foot sunroom with electrical wiring and heating.

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Home Addition Costs by Style

How much a home addition costs can vary by style, whether you are adding a simple bump-out or an entire second story.


For a balcony addition, expect to pay roughly $5,000 to $10,000. Adding a balcony is a less expensive alternative to porches or decks if you want more outdoor space.


A bump-out home addition costs about $5,000 to $10,000 and is a small addition to an existing room to add more square footage. This is one of the least expensive home addition options, but it also tends to add the smallest amount of space to a home.


A cantilever typically costs $15,000 to $25,000 and is a home addition on an upper floor that juts out past the first floor. This style requires additional support beams either angled and attached to the house or anchored into the ground.


A dormer addition costs between $5,000 to $10,000, but this doesn’t include the cost of a total attic conversion. Dormers add charm to any home, but they can also add functional space to the attic. A dormer is an addition that extends from the roof with a window.


Adding a garage typically costs $25,000 to $50,000 depending on whether or not you want an HVAC system and electricity. Adding a garage is ideal if you want covered shelter for your car, a space for handy work, or additional storage.

In-Law Suite

In-law suites generally cost $50,000 to over $100,000 because this requires building living spaces, a bedroom, a bathroom, and a kitchen. An in-law suite is a small studio or apartment that adds separate living quarters to your property.

Modular Room

Modular or prefabricated rooms cost between $20,000 and $30,000 total or around $25 per square foot. This is a less expensive option for a home addition because it is manufactured and delivered to your property, but it often has fewer customization options. Note that you should speak with an architect or contractor before adding a room to a modular home, as it may not be equipped to support an addition.


For a 200-square-foot porch addition, expect to spend about $5,000 to $25,000. A new porch can add extra square footage to your home while also offering a space to take a breath of fresh air.

Second-Story Addition

This addition can cost upward of $500 per square foot. A second-story addition is one of the most expensive additions because it requires adding an entire level to the home by removing the existing roof.

Home Addition Cost by Size

A home addition costs about $80 to $200 per square foot, including materials and labor. For a second-story addition, the cost is likely to be higher at around $300 to $500 per square foot.

Square FootageCost
100$8,000 – $20,000
200$16,000 – $40,000
300$24,000 – $60,000
400$32,000 – $80,000
500$40,000 – $100,000
600$48,000 – 120,000
700$56,000 &– $140,000
800$64,000 – $160,000
900$72,000 – $180,000
1,000$80,000 – $200,000

Home Addition Cost Factors

The cost of a home addition ranges widely based on the style, size, and type of addition plus the various materials and labor costs. But the final cost can also depend on other factors, like excavation costs and permits.

  • Permits: Building a home addition often requires a permit from your city. This will cost about $400–$2,000.

  • Materials: The cost of materials can vary a lot based on the types of floors, paints, and finishes you choose.

  • Excavation and Demolition: To extend your home, there will need to be demolition and sometimes excavation to prepare the site for the new addition. This site preparation will cost about $1,500–$5,000, although for bigger projects, like adding a second floor, installing a basement, or converting an attic, these costs can be closer to $10,000.

DIY vs. Hire a Home Addition Pro

Home additions should be left to the pros, and there are many experts you’ll need to hire for this job. To take the burden off of you and to get the best result, hire a general contractor experienced with home additions. The general contractor will handle hiring and working with all the other pros as part of the service.

Labor costs make up 30% to 50% of a home addition project’s budget, but it’s important to invest in hiring the right professionals for each job. Building a home addition is not recommended as a DIY project. This process involves demolition, construction, electrical work, and possibly plumbing.

It’s dangerous to attempt construction and electrical work yourself, and you could also make costly mistakes if you don’t correctly lay the foundation or build the support beams. If you are skilled at some tasks, like painting or flooring, you could save money by doing those components yourself.


Does an addition add value to my home?

Investing in a home addition can give you more space, but it may also increase your home value if you decide to sell.

  • Bathroom: 53% ROI

  • Master Bedroom and Bathroom: 63% ROI

  • Sunroom: 49% ROI

  • Two-Story Addition: 65% ROI

How long does building a home addition take?

A new home addition can take several weeks or even months to complete. On average, a home addition takes 2 to 3 months to build. However, due to the ongoing industry-wide supply-chain issues, you might want to plan for the building process to take a little longer.

Do I need to hire an architect?

An architect can help ensure that your home addition matches seamlessly with the rest of your home. It’s usually not required to hire an architect for a home addition, but these services can help the addition look and function its best. Adding a home addition without proper architectural drawings is very risky. A professional architect will save you a lot of headaches and costs down the line.

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