How much does a home addition cost?

To get an estimate of what your home addition may cost, consider the square footage of your addition. The size and scale of the addition can let you know what to expect when planning your budget.

This chart from HomeAdvisor provides home addition cost estimates based on the addition's square footage.

Factors that determine the cost of your addition

Be sure to understand the scope of your home addition project, as it will impact your overall cost the most.

Keep the following variables in the back of your mind:

• Size of the addition: A big factor in the total cost of the project is the square footage the addition will cover. Most home additions cost $80 – $200 per square foot, on average. The larger the project, the higher the cost in most cases. For example, an average 20 x 20 square foot room would cost approximately $32,000 – $80,000.
• Site preparation: Before building anything, the building site must be prepared. This can include excavation, demolition or simply clearing the area. But depending on the work required, you could be looking at a cost of $1,500 – $5,800.
• Location: Construction costs will vary from city to city and state to state, so what you pay will depend on where you live. Projects in larger urban cities tend to cost more than the same projects cost in other areas. Your home's market value and the cost of labor and materials in your area drive construction costs.
• Permits: Home additions are usually a major renovation, so you'll likely need to get a building permit from your local officials. Before you can proceed with your construction, it's likely you'll pay somewhere in the $400 – $1,850 range to obtain required permits.
• Labor: If you need to hire professionals, labor costs will likely make up 30% – 50% of the total project cost.
• Building materials: Your home addition will require several types – from wood to drywall to air ducts and more, and the costs will vary greatly. It's important to consider current market prices for these materials before starting your project.
• Architect fees: An architect can design and draw up blueprints to ensure your addition will be functional and seamlessly match the rest of the house. This type of service typically comes with a flat fee in the $2,000 – $10,000 range.
• Cleanup: Home additions generate a significant amount of debris, excess materials and dirt. Your contractor will likely include time and labor in an estimate for the cleanup process. Post-construction cleanups often cost around $550.

Home addition cost: features

Depending on the project, you may need to factor in costs for a few features into your build. They include: 

• Roofing:Any room or enclosed structure added to your home will need a roof overhead. The roofing materials you pick will affect the total cost of the addition, but you can typically expect to pay $4 – $40 per square foot for a roof installation. However, this doesn't include the necessary support beams and trusses you'll have to purchase.
• Ceilings and walls: Any room with a roof will have a ceiling and walls. Most projects will require drywall to cover electrical wiring and insulation. Installing drywall can cost $1 – $3 per square foot, and insulation will be around $2 per square foot.
• Siding and trim:​​​​ ​It's common for home additions to require siding and trim to ensure the house has a uniform look. Typically speaking, the combined cost for siding and trim is $1 – $30 per square foot.
• Flooring: Your flooring costs will depend largely on the materials you choose. You can usually expect to spend anywhere from 50 cents to $15 per square foot to install a new floor.
• Foundation: An addition like a garage or an extra room will require a new foundation. Depending again on materials, costs can start out at around $4 per square foot. If your addition is a basement, a new foundation will cost considerably more and probably be $30 – $100 per square foot.
• Electrical and plumbing: With most additions, you'll need to add electrical work and plumbing to the new section of your home. The electrical work will cost you an electrician's hourly rate, which is usually around $40 – $100. Plumbing will be around $45 – $200 per hour. These professionals will make sure everything is up to code and ready to pass inspection.
• HVAC: If your new space requires heating and cooling, you'll need to consider the cost of new ductwork and vents. The average price of a new HVAC system is $8,000.
• Fixtures and appliances: Depending on its function, your new room may need fixtures such as doors, windows and appliances. Exterior doors typically cost $500 – $2,000 to install, while interior doors tend to be in the $250 – $1,150 range. The average cost of installing windows runs between $235 and $2,500. Also be mindful of any appliances you'll want in the new space and whether you'll need to hire an electrician or plumber for installation.

Home addition cost: DIY vs. contractor

If you're not the DIY type, you may want to hire professional help for your home addition, which is likely to require a considerable amount of skill and labor. You may be able to save money by completing smaller parts of the project yourself, but you'll likely need to bring in a professional for the more complex or specialized aspects of the job.

Home addition cost: type of addition

A home addition can add an entirely new room to your house and provide a slew of new possibilities. Below, you'll become familiar with these common home additions and the typical costs for such add-ons.

Room addition

• Kitchen: Most houses already have a built-in kitchen, so this type of addition can be more of an expansion. On average, a kitchen remodel costs $12,000 – $33,000. You should budget accordingly to ensure you can finance your kitchen remodel. If you're adding a new kitchen, costs could be closer to $20,000 – $90,000.
• Bathroom: While a bathroom remodel can be less expensive, a new bathroom is one of the most costly home additions you can make. Bathrooms require a large amount of plumbing to be installed, even in a small space. Flooring and fixtures cause the costs to add up quickly. The average bathroom addition costs around $35,000 – $90,000.
• Bedroom: An extra bedroom costs an average of $100 – $155 per square foot after roofing, flooring, foundation and other fixtures. A smaller room – one that's 12x12, for example – will run you $12,400 to $22,300 on average. A larger room, such as one that's 20x20, gets you into the $34,400 to $62,200 range.
• Laundry room: Adding a laundry room to your house will set you back around $8,070, on average.
• Home theater: If you're adding a theater to your home, consider the additional costs of soundproofing and specialty electrical work. On average, a home theater costs $70,000 – $90,000.
• Sunroom: Sunrooms can be ideal for relaxation and enjoying the perfect view of the outdoors. Homeowners typically spend $100 – $350 per square foot just on materials. To save time on construction, some homeowners opt to buy prefab sunrooms for $300 – $400 per square foot. You'll still have to cover the costs for the foundation, roofing, flooring and electricity.
• Mudroom: A mudroom can act as a vestibule to place your coat and shoes. You can also use it for storage or doing laundry. Adding a mudroom can cost $90 – $200 per square foot. Be sure to also consider the cost of any appliances you'll want in your mudroom.
• Family room: A functioning room for the whole family to enjoy will cost approximately $86 – $200 per square foot. For instance, a 500-square-foot family room will be priced in the $43,000 – $104,000 range, which covers various installations as well as electrical and plumbing work.

Home extension

• Bump-out: A bump-out extends the space of an existing room within your home. The cost of this project depends largely on the preexisting structure and materials. Typically, it's in the range of $5,000 – $10,000.
• Garage: The cost to build a garage is customarily $35 – $70 per square foot. A garage usually requires fewer fixtures and appliances to function, making it a cheaper home addition. If your garage is attached to your home, you can save around $3,000 – $5,000. Even so, various options for garage financing are available and provide some flexibility with this home addition.
• In-law suite: At some point, homeowners may want to move their parents or in-laws onto their homes. Some people opt to build an in-law suite, which usually functions as a smaller apartment for one or two people. An in-law suite is typically 600 – 750 square feet, which includes a bedroom, living room, bathroom, kitchen or kitchenette and a laundry area. For a fully detached in-law suite addition, you could pay $50,000 – $100,000.
• Porch: A porch can extend the entertainment or functional space of your home's exterior. Whether planning for a small screened-in porch or a full wraparound porch, you can expect to pay $12,000 – $30,000.
• Balcony: Interested in adding a balcony for a private outdoor space on an upper level? This addition will typically run you $5,000 – $10,000.

Second-story addition

Some homeowners would rather expand upward than outward. Adding an entire second floor can be a complex – and expensive – home addition, especially if you plan to build multiple rooms on the new floor.

Minus any foundation costs, you're basically constructing a new house on top of your current one. Framing, drywall, electrical and plumbing costs will all apply here. You'll also have to pay for roofing and flooring. In the end, this project may cost around $500 per square foot depending on design and materials.

How to finance a home addition

When looking to fund a home addition, you'll have several financing options to consider and choose from for your addition.

• Personal loan: People often take out a personal loan for a home improvement project. Once approved, you can borrow up to a specific amount to finance the costs of your home addition. You can also receive these funds in a relatively quick time frame.  Personal loans often come with flexible repayment terms, and many don't require collateral.
• Home equity loan: A home equity loan allows you to borrow a certain amount from the equity you've built in your home. Some home equity loans come with a relatively low, fixed interest rate, but be aware that your house will serve as collateral for this type of loan. To avoid the possibility of losing your home, be sure to repay the loan on time.
• Home equity line of credit: Similar to a home equity loan, a home equity line of credit (HELOC) lets you borrow funds against the equity you have in your home. Again, though, your house acts as collateral for the loan, so making on-time payments is crucial. The difference between a home equity loan and a HELOC is that a HELOC is a form of revolving credit rather than a lump sum, so you can use and repay funds as needed during what's known as a draw period.
• In-house financing: Some businesses have in-house financing plans that they offer customers. Check with any professionals you hire to learn about their payment options.

Are home additions worth it?

The benefits of a home addition often outweigh the investment you put into the project. Here are a few reasons you might consider adding onto your home:

• Your overall space and storage will be expanded.
• Your property value could increase from the addition.
• Home additions can allow you to enjoy your home for a longer period of time.
• Growing families may not need to find a new home, thanks to the addition.

House addition cost FAQs

Still wondering if a home addition is worth the financial commitment? Here are answers to a few questions that people frequently ask about home additions and their costs.

Do I need an architect for a home addition?

Whether you need an architect for a home addition will depend on the type of addition you're making. For example, you may want to consider using an architect for major structural changes. Architects will make sure the new addition is stable and code compliant. Less complex additions may not require an architect.

Is it cheaper to build up or out?

Building up tends to be less expensive than building out. If you add a story onto your house, you'll avoid paying costs for digging and laying a new foundation.

Does an addition bring more value to a home?

Adding space to your home usually increases your property value. The amount of value the project adds will depend on the size and type of addition you make.

Final thoughts: A home addition's value may outweigh its cost

Home addition costs can skyrocket in a hurry. If you're the handy type, you may save on labor costs by going the DIY route. If yours is a time-sensitive project, however, the speed and precision of a professional contractor may be worth the extra cost. Ultimately, a home addition should boost your home's value and create extra space for you, and perhaps others, to enjoy.