Updated September 6, 2024
Reviewed by Ezra Laniado, Expert Contributor. Written by HomeAdvisor.
Highlights
A home addition costs about $50,295 on average and typically ranges between $21,976 and $82,280.
A home addition costs about $80 to $200 per square foot.
Adding a second story to an existing building costs more than building outwards.
Plumbing, electrical, and other components add to the complexity and cost of home additions.
Adding a primary bedroom with an ensuite bathroom costs as much as $100,000.
Professionals to hire for this project may include architects, construction managers, general contractors, and structural engineers.
Home additions can increase home value with an average ROI of 20% to 50%.
The national average home addition cost is around $50,295, including balconies, bump-outs, and extra rooms. The cost varies greatly based on size and complexity, typically between $21,976 and $82,280. As you work through your home addition cost estimator calculations, know that this figure can quickly surpass $100,000 or more with different room types, styles, sizes, and materials.
In this article
- Home Addition Cost Calculator
- Home Addition Cost Factors
- Additional Cost Factors
- Home Addition Cost by Room
- Home Addition Cost by Location
- Home Addition Labor Costs
- Does an Addition Increase Home Value?
- Budgeting for a Home Addition
- Cost Methodology
Home Addition Cost Calculator
Let's calculate cost data for you. Where are you located?
Where are you located?
| National Average | $50,295 |
| Typical Range | $21,976 - $82,280 |
| Low End - High End | $4,000 - $155,000 |
Cost data is based on actual project costs as reported by 5,477 HomeAdvisor members.
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Home Addition Cost Factors
When you meet with home addition builders in your area to discuss your project, review the various factors determining how much a home addition costs. The three main factors are size, materials, and type of home addition.
Size
Most home additions cost $80 to $200 per square foot, including labor and materials. Larger home additions cost more than smaller ones. If you’re adding a second story, expect these costs to increase to between $300 and $500 per square foot.
| Square Footage | Average Price Range |
|---|---|
| 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 |
| 1,000 | $80,000–$200,000 |
Materials
The building materials you use in your home addition affect your total cost. The cost of buying doors, roofing, windows, insulation, and paint all add up. Using different types of materials also influences price and increases the project's complexity. You may also need to pay for electrical and plumbing parts and HVAC components.
| Material | Average Cost |
|---|---|
| Exterior doors | $500–$2,000 each |
| Interior doors | $250–$1,150 each |
| Drywall | $1–$3 per sq. ft |
| Framing | $40–$150 per 100 sq. ft. |
| Flooring | $3–$20 per sq. ft. |
| Foundation | $4–$100 per sq. ft. |
| Insulation | $2–$5 per sq. ft. |
| Paint | $2–$5 per sq. ft. |
| Roofing | $75–$600 per sq. ft. |
| Siding and trim | $1–$30 per sq. ft. |
| Support beams | $1,150–$4,600 each |
| Windows | $250–$2,000 each |
Type
Your project cost also depends on the type or style of home addition.
A balcony addition costs $2,000 to $10,000 on average, which is generally less than building porches and decks.
A bump-out addition costs an average of $5,000 to $10,000. It’s one of the least expensive home addition options.
A cantilever costs around $15,000 to $25,000 on average, adding square footage to the upper floor of a home with support beams.
A dormer addition costs $2,500 to $30,000. It adds a roofed structure with a window to increase the usable space in a loft or attic.
The cost to add a garage ranges from $25,000 to $50,000, depending on whether you want to include HVAC and electricity.
In-law suite additions cost the most at $50,000 to over $100,000. They offer a small studio or apartment as separate living quarters.
Adding a modular or prefabricated room runs you $20,000 to $30,000.
The cost to build a porch ranges from $5,000 to $25,000. It adds outdoor square footage to your home.
A second story addition costs as much as $500 per square foot, making it one of the most expensive home addition types.
Additional Cost Factors
As you estimate your home addition costs, consider these other factors that can greatly increase your overall price.
Excavation and Prep
You may have demolition and land excavation costs to prepare the site for the new addition. Excavation costs about $1,500 to $5,800, although these prices can be closer to $10,000 for bigger projects, like adding a second floor, installing a basem*nt, or converting an attic.
Permits
Home additions can make significant changes to the structure of a house, so most jurisdictions require you to apply for the appropriate permits. Building permit costs depend on your local authorities and the nature of the project. They can range from $200 to $3,000.
Cleanup Costs
As with any other construction project, home additions also involve cleanup. Construction cleanup costs around $470 on average. Most general contractors can handle the rough cleanup, but you may need other professional help for a final, more thorough cleaning.
Insurance
While you may be primarily concerned with how much your home addition costs to build, it’s equally important to consider the long-term ramifications. Your existing home insurance policy may or may not cover home additions, especially if you substantially increase the value of your home. At the same time, you may need to add “dwelling under construction” coverage. Speak with your insurance provider to clarify what may apply in your case.
Home Addition Cost by Room
Different rooms have different needs and unique characteristics, so the type of room you add to your home also impacts the total cost of your home addition project.
| Room | Average Cost |
|---|---|
| Attic | $40,000 |
| Bathroom | $35,000 |
| Bedroom | $62,500 |
| Dining room | $35,000 |
| Kitchen | $55,000 |
| Laundry room | $8,070 |
| Living room | $30,000 |
| Mudroom and sunroom | $12,000 |
Attic
Converting an attic into a livable space costs about $40,000. Unlike other home additions that add square footage, finishing an attic has more to do with having enough insulation and ventilation for comfortable year-round use. Remember to account for the cost of installing a staircase to access this room.
Bathroom
Adding a bathroom costs $15,000 to $35,000 while adding a more luxurious and larger 100-square-foot bathroom costs about $90,000. Bathrooms are a more expensive addition because they require plumbing and fixtures like showers and toilets.
Bedroom
A primary bedroom addition costs around $62,500, but if you plan to add an ensuite bathroom, expect to spend up to $100,000.
Dining Room
A standard dining room is about 14 by 16 feet and costs about $20,000 to $45,000 to add to your home. Expect to pay more for a wet bar or built-in cabinets and shelves.
Kitchen
A kitchen addition costs anywhere from $20,000 to $125,000. Kitchens are among the most expensive home additions because they require electrical work, plumbing, and appliances.
Laundry Room
A laundry room addition costs about $8,100 on average. This includes the cost of newer appliances, additional storage, and waterproof flooring.
Living Room
A 12-by-18-foot living room or family room adds about 216 square feet to your home’s living space and costs about $20,000 to $45,000. The cost increases for larger rooms with high-end finishes and custom entertainment centers.
Mudroom and Sunroom
Adding mudrooms and sunrooms costs around $8,000 to $16,000. 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. Expect to spend $8,000 to $11,000 for a simple sunroom or upward of $80,000 for a 200-square-foot space with electrical wiring and heating.
Home Addition Cost by Location
Construction costs vary drastically depending on where you live. There are regional differences in the cost and availability of labor and the ready availability of preferred building materials. Some average home addition costs are listed below.
| City | Average Price Range |
|---|---|
| Oklahoma City, Oklahoma | $5,000–$17,000 |
| San Antonio, Texas | $12,500–$36,000 |
| Memphis, Tennessee | $17,000–$38,000 |
| Charlotte, North Carolina | $17,000–$52,000 |
| Tampa, Florida | $22,500–$61,500 |
| Portland Oregon | $22,000–$70,000 |
| Seattle, Washington | $26,500–$92,000 |
| Philadelphia, Pennsylvania | $27,000–$84,000 |
| Boston, Massachusetts | $27,500–$93,500 |
| New York, New York | $26,500–$109,000 |
| Los Angeles, California | $54,500–$129,000 |
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Home Addition Labor Costs
Successful home additions require skilled laborers. Depending on the details of your project, you may need design services, demolition contractors, and other home addition pros. Reserve upwards of 50% of your overall project budget for installation costs.
Architects
A great home addition starts with a solid plan. A local architect can help ensure that your home addition seamlessly matches the rest of your house. The average cost to hire an architect typically makes up 5% to 20% of your total project budget.
This is more than the cost to hire a draftsperson because the architect is much more involved in the actual design of the home addition. In contrast, the draftsperson may be responsible for drawing the detailed plans that the architect creates.
Construction Managers
Construction managers oversee the entire project, hiring subcontractors and managing everything needed to get the job done. They may also apply for the relevant building permits on your behalf and collaborate with the architect for clarification and guidance. Average construction manager fees take up 5% to 15% of the project total.
General Contractors
After the architect has drawn up the designs and everyone is in agreement, general contractors perform the general labor needed to make your home addition a reality. This may include laying the foundation, framing, roofing, drywall, and paint. For home additions, general contractor rates range from 10% to 20% of the project cost, also called “cost plus.”
Electricians
Many home additions involve some level of electrical work. The project's specifics vary considerably, so ask local electricians for quotes specific to your home addition. Expect to pay $50 to $130 per hour for standard work.
Plumbers
While you may not need to find a local plumber when adding an extra bedroom, plumbing is crucial for kitchens and bathrooms. Pro plumbers can ensure sinks, showers, bathtubs, and other similar fixtures are installed properly. Plumbers charge anywhere from $45 to $150 per hour with a minimum service fee.
Structural Engineers
Whether your home addition builds up or builds out can affect your home's structural integrity and foundation. To ensure everything is up to code, consult a structural engineer in your area to review the home addition plans and inspect the construction once it’s completed. The cost to hire a structural engineer ranges from $70 to $250 per hour.
Does an Addition Increase Home Value?
In general, home additions do increase home value. When it comes time to sell your home, you can recoup some of the construction costs. The return on investment varies based on the type of home addition. Adding a primary suite or bathroom to your home has an average ROI of 22% to 30%. Outdoor deck additions have an ROI of 40% to 50%.
Budgeting for a Home Addition
Consider these money-saving tips for your next home expansion project to maximize your budget without compromising on quality:
Stick to simpler designs focusing on functionality to help stretch your budget.
Choose standard sizes for windows and doors. Custom sizing can be much more costly.
Reuse or repurpose existing materials where possible.
Consider buying energy-efficient materials and components to save on long-term costs.
Ensure all plumbing, electrical, and HVAC work is done correctly the first time to avoid expensive repairs or upgrades later on.
For most home additions, build outwards rather than upwards. It’s cheaper than building upwards with additional stories.
Get multiple bids from several local contractors to secure the best price.
How HomeAdvisor Gets Its Cost Data
No place is more important than your home, which is why HomeAdvisor connects homeowners with local pros to transform their houses into homes they love. To help homeowners prepare for their next project, HomeAdvisor provides readers with accurate cost data and follows strict editorial guidelines. We surveyed thousands of real 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.
Still Have Questions About Building Home Additions?
Frequently Asked Questions
Is it less expensive to build out or build up?
When building an addition, it's usually more cost-effective to expand your footprint and build out than to build on top of an existing structure. This question is often confused because the opposite is true for a new build.
Generally, building out for a remodel is cheaper than adding a second story to an existing dwelling. By contrast, building up is more affordable than expanding the footprint for the new construction of a single-story home.
How long does a home addition take to build?
A home addition can take two to three months to build. Simpler additions, like bedrooms and dens, take less time than more complex additions, like bathrooms and kitchens, that may require additional electrical or plumbing work. These timelines assume that all materials and labor are readily available. Supply chain issues or waiting for the necessary building permits can delay construction.
Is it cheaper to build a house or add-on?
Generally, it’s less expensive to build an add-on than it is to build a new house. Add-ons typically cost $22,440 to $80,930, while a new home build costs $112,040 to $448,950, on average. However, if your project is a complex addition—such as a luxurious 100-square-foot bathroom with new plumbing—multiple add-ons, or a second-story addition that requires removing the roof, your total cost can quickly approach the cost of a new build.
What is a good size for a family room addition?
The standard size for a family room addition is about 12-by-18 feet, or 216 square feet, which can comfortably fit a six-person family. The ideal family room size depends on several factors, like your family size, the size of your furnishings, and whether you prefer a cozy or more open space.
How far can you bump out a house?
Check with your local building codes and regulatory bodies to determine how far you can bump out a house in your area. A footed bump-out extends the farthest, while a cantilevered bump-out extends four times the depth of your existing joists. This is the most common bump-out type for home additions. Contact a home addition contractor in your area for further guidance.
How much does it cost to add 1,000 square feet to a house?
Costs can vary based on many factors, like if you decide to add a second story to your single-story home or expand its footprint by building outwards. The average home addition cost is anywhere from $80 to $200 per square foot. So, you should budget at least $80,000 to $200,000 to add 1,000 square feet to your house.
